December 7, 2017 • 53 mins
What is now? What is the present moment? These questions continue to stagger us, for nothing is so simultaneously familiar and alien than the passage of time. Nothing seems more “real” to us that the present, yet it vanishes into nothing at every attempt to capture or quantify it. In this special two-part episode of Stuff to Blow Your Mind, Robert and Joe dive into the experience, physics, philosophy and neuroscience of now.
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Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind from how Stuff
Works dot com. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb and I'm Joe McCormick, and
we're back for part two of our discussion of this
present moment, the now, and we're trying to get inside
(00:23):
the now. So in our last episode we talked some
about the physics of now, but the history of time
keeping and about the physical concept of now, of the present,
and whether there is such a thing as now. Now.
We're going to keep doing this, probably accidentally several time
and now all the time, but physicists in general would
(00:44):
probably say that there is no such thing as now
from a universal point of view, that relativity shows us
that there isn't simultaneity across the universe, and there's no
external objective way to to sort synchronize events into and
now in the timeline of the universe right and and similarly,
(01:06):
you can't say I'm gonna do x uh eight now's
from right now. It just doesn't work. Yeah, there's no
apparent unit of now in in physical time keeping either.
But physics aside, we still do have this profound sense
of the present. I mean there's a reason these concepts
appear in our language. Why do we have a word
for now? Why do we have a word for the
(01:27):
present if there isn't something relevant going on there? So
this time we wanted to explore the philosophy of the present,
the philosophy of now, and the psychology and neuroscience of now.
What's going on in our minds when we perceive a
present moment, when we think about what's happening right now?
You know, I know I've mentioned New age and spiritual
(01:48):
author Eckart Tootle on the show before and how I
found some of his ideas concerning mindfulness rather helpful. Uh,
And what his central thesis is that the present is
is all we have and this too, being part of
time is an illusion. Oh great, so we've got nothing, Well,
you've got, but there's a lot to be had and nothing.
(02:08):
Here's here's a quote from totally. He says, quote time
isn't precious at all because it is an illusion. What
you perceive as precious is not time. But the one
point that is out of time the now. And I
really like that the idea that maybe we shouldn't think
of now as a point within time, but a point
(02:29):
outside of time. Yeah, I kind of like that too.
I think it might be easy for, you know, some
kind of hard science minded people to think of that
as like, oh, that's just new age nonsense, that doesn't
mean anything. I think that kind of does mean something.
I mean, think about your experience of time. What do
you have the power to act on in your own experience? Like,
(02:53):
what point of time do you have the power to
do something about. You can't really do anything about the
past past, because it's already happened. You can remember it,
but you can't change it except in your memory by
distorting it. And don't underestimate the power of that. No,
that can happen, but you can't actually change what happened
in reality. You can change your memory, but the past
(03:13):
is gone. You can't really change the future because it's
not here yet. You don't have access to it. Right,
So it's you know, you don't have any power over
things that are causally disconnected from you down the chain,
And in a weird way, you almost don't really have
the power to change the present either, because it's happening.
That's right, it's happening right now, at least as you
(03:34):
sense it. I mean, to whatever extent there is such
a thing as the present in our experience, it's what
you're experiencing, not really what you're doing. So where where
do you live? Where does action happen? Where does change
take place? Yeah? Is it? To what extent? Is it?
Is it a conscious thing? Is it is? It? Is?
It's subconscious? Is it a series of subconscious processes that
(03:56):
are going on? Are we all as as our friend, uh,
Scott Baker who put it, Are we all just slaves
to the darkness that comes before and therefore there's no
there's no real choice or or or agency at all. Well,
I'd say that I think our Scott Baker and Eckhart
total are on exactly the same page here that it's
just a question of whether you make it sound positive
(04:17):
or make it sound negative. I never thought of that before. Now,
wouldn't you kind of agree? Yeah? Yeah, I think there's
a valid point. Yeah, Uh, totally is just totally is
selling a a more positive vision of what the world
can be, um and uh and Baker baman not. That's
not to say that Baker doesn't have some optimistic ideas
in mind, but he has a much darker vision of
(04:39):
of of reality of course, and this we're already getting
into the realm of philosophy, right, and there is a
heck of a lot of philosophy of time out there.
Oh yes, yes, yeah, I mean the nature of the
present moment is it's tied up with our experience of reality.
So it is of course the domain of philosophy. It's
one of the most argued about topics in all the philosophy.
(05:00):
You have multiple different schools of thought that weigh in
on the nature of now and time and the place
of time, of now in time, and we could we
could podcast until the end of time about just the
various approaches to this. Yeah. I would say one reason
that philosophy of time is so popular is because it's
so closely related to the philosophy of the perception of
(05:22):
free will. Um. This came up actually just a minute ago,
and what I was talking about comparing you know, our
Scott Baker and Eckartley. In both cases, I think they
might be add I don't want to speak too much
for totally, but I think in both cases it sounds
like they're advocating a universe in which we just kind
of accept that we are not necessarily the causal agents
(05:43):
ourselves that bring about change. That we have the experience,
you know, sort of the sensation of being behind our
own actions. But you can't get behind the behind the actions.
You know that that you as you are acting now
or a product of things that came before, and though
those consequences that came before, we'll have consequences that echo
(06:03):
into the future. But you don't necessarily have free will
in the classical sense under this understanding of time, because
where would the free will take place? What would happen?
What changes in the now? Alright, So so let's just
roll through some of the broad categories of philosophy of
time and the now, uh, and and again again. Each
(06:24):
of these is a topic that we could easily do
an entire podcast episode on and and maybe very well
returned to in the future. So first up, we have
to touch on fatalism. My favorite. This is the notion
to him that the future is unavoidable. With enough data,
or perhaps a robust enough simulation, you could accurately predict
all future events. What's more, you wouldn't be able to
(06:45):
avoid those events. The future is not open, but rit
closed in inexorable, and this entails a good bit more
than the present, but we'll see how it all ties in. Shortly,
I would say that this point of view and my
experience is more popular with physicist than it is with philosophers,
because a lot of philosophers, I think, are are caught
up in the idea of explaining agency, like they're really
(07:07):
trying to find free will and agency and our actions.
But you know, physicists just say, well, look at what
the math says. It looks. You know, every indication from
our mathematical model of the universe is that past and
present and future they're all just part of the same block.
And that's a block of the universe that exists. So
(07:27):
what how how could you change it? In what sense
would you be altering the future? Up next, we have
a reductionism with respect to time. So the idea here
is that time does not exist independently of the events
that occur in time. When we talk about time, we're
talking about temporal relations among things and events. And this
was an argument of Aristotle and many others. So where
(07:50):
do you think this would fit into our idea of
modern physics? It seems like modern physics except for the
people who don't believe in time like you know, Julian
Barber and all those. Most modern physicists would probably not
agree with this, would you say, because spacetime is spacetime? Yeah, yeah,
I would think so. Up next, we have platonism, as
in Plato with respect to time, Plato, Newton, and others.
(08:13):
They counter reductionism with respect to time. The general ideas
there with the idea that time is the independent container
in which all else is stored. Okay, so this sounds
a little bit more like the spacetime idea, like spacetime
could exist without the objects in it. Maybe. Yeah. Now
this next one is a doozy and it takes us
(08:33):
all the way up to Uh. This is mc taggart's argument,
which he made in his work The Unreality of Time. J. N. E.
McTaggart argued that there is no such thing as time.
He argued that there are two ways to order time,
A series in which we measure everything by its relation
to the present, and B series, in which we measure
(08:55):
things by the relationship between two moments in time. Each
one comes with it share of complications and Nictaggart believes
that time containing both A and B series is not real,
but other thinkers have come along to accept either A
or B rather than reject time itself. So this is
sort of asking the question of whether time actually flows, like,
(09:15):
is there such a thing as the present? Is there
happening in the universe? And if things really do happen,
that would seem to be the A series, Right. If
if there's a present moment moving along through the history
of the universe, that that's the A series, and the
B series would be that time is just a It's
just a measurement between change events, right, So that the
(09:37):
subset here people who latch onto A or B A
theory is that is that A series is all there
is and anything that looks like B is really A.
In other words, time passes yet a past a present
in the future. This is also referred to as the
tensed view of time. And you have B theory, which
this say is B is all there is, anything that
(09:58):
looks like A is actually be and time time does
not pass the tense less theory of right. You know,
we talked about this, and I think maybe we should
come back in the future outside of this discussion of
the present moment and now to do a whole episode
on the idea that time doesn't exist, because I think
this is not a majority viewpoint among physicists. You know,
the majority physicists might say nothing actually happens. There is
(10:20):
no present moment in the universe, but there is a
time in the universe. Right. It's it's such a mind
blowing topic that we we do need more time to
consider it, and we will come back to it at
a future point in time. Right, that's when we'll discuss
that there's no such thing as time. Of course, it's
all an illusion. But yeah, so hopefully then we can
(10:41):
talk about Julian Barber and McTaggart and the others who
agree with them. Alright, So moving along with the sort
of broad schools of the philosophy of time, we have
a present is um. This is an a theorist approach
that states that only the present exists. Things outside of
the present. So the claw source of roads, Genghis Khan,
(11:02):
or the next Fast and Furious movie does not exist.
They just literally are not real until they are currently existing. Right.
If it's not currently existing, it's not a thing, be
it Genghis Khan or or or a movie that is
inevitable but not yet made. So the only thing that
(11:23):
exists is the present moment, and the past and the
future are not real and do not exist. Uh yeah,
that seems like it would be hard to make sense
of for me, It would be hard to make sense
of that picture of the universe given um, given like
the lack of simultaneity you know, across the universe and
the fact that things can appear out of order to
(11:44):
different observers based on the speed of light and all that,
right exactly, so, we have another another argument that might
work better with all that, and that is eternalism. This
is one of several non presidentism approaches, and it argues
that objects from the past and future exist. We can
call these non present objects. They exist just as much
(12:05):
as present objects. So the Clossus of Roads and Genghis
Khan exist just as much as you and I, even
if they are no longer present. And here's the other thing,
the inevitable next the Fast and the Furious movie is
much the same. It's as real as anything that's around
right now or existed in the past. But that's only
because it's actually going to happen. It's not like hypothetical
(12:27):
future things that never actually happen exist right now. Well,
that's the thing, it's ultimately hypothetical because something could occur,
or a series of things that could occur that would
obviously prevent the next Fast and Furious movie from happening.
But in that case it never would have existed to
begin with. Yeah, I mean, I mean, I would say
under this model, only the future that actually happens to
(12:49):
come to exist exists right now. But of course we
never got another Interspace movie, we know when we never
got to explore future um miniaturized adventures inside of Martin
short stomach. Oh but we will because Hollywood will continue
to be out of ideas for new things, and they
will just revisit old franchises until they're plowing into like
(13:11):
Police Academy reboots and stuff, and they've got to get
to Interspace two before they do the Police Academy reboot.
All right, well, I look forward to Interspace too, even
if I'm ultimately disappointed at how overwhelming the c g
I is. Alright, Beyond this, we have the growing Block
Universe theory of time. This is an anti presidentism approach
in which the universe is continually getting bigger because of
(13:33):
all this stuff we keep adding. So we're you know,
we're front loading time with new time, new stuff, new
space time. So every second that exists, we're essentially adding
a room onto the house because there's more for the
universe to contain since it contains past and present. Okay,
and then just a one added note on time travel
that I thought was interesting. So time travel cannot happen
(13:55):
in an eighth theory theorist president is um because the
present is all their is, so you can't travel into
the future of the past. Uh. And of course you know,
in addition to all the backward this is an addition
to all the backward causation is impossible talk, which is
all fruit for another discussion. Yeah, well, I think backward
time travel is also impossible under b theory, right. Yeah, well,
(14:18):
I mean I would say that that that is my
understanding as well. But we're really overdue too for a
proper time travel discussion on this show. Yeah, well, I
think we should take a quick break and when we
come back, we will start to look at the psychology
and neuroscience of our experience of now, what what happens
to the mind on the present moment? Thank alright, we're back.
(14:40):
So in our previous episode, we talked a little bit
about mental time travel uh in memory and how these
are core to our experience of time as flowing. We
remember what has come before, we anticipate and use mental
time travel or chronasthesia to understand what is going to happen.
And then we have to wonder what what what would
it be like to be un shackled from these I
(15:01):
mean that's kind of cord to a lot of meditative
exercises or even the flow states that we get into
with our our work or our hobbies, like what what
can we do to cut off the default mode network
and no longer worry about the past and the future
and live in the quote unquote present. Well, some answers
to this question can be found in an individual known
(15:24):
to psychologists as Patient K. This is a Toronto resident
who suffered severe brain damage during a motorcycle accident, and
he lost his episodic memory. So it's important to note
here he can still do all the things he learned
to do prior to the accident thanks to his procedural memory. Right, so,
if you lose your ability to make memories, you still
(15:45):
probably remember how to tie your shoes, right, you can't
remember what you had for breakfast? Right. So this guy
can speak, he can play games that he learned previously,
He can navigate his his neighborhood without becoming lost. But
he cannot remember what he did yesterday, and he cannot
acculate on what he's going to do tomorrow. He has
no autobiographical memory at all. Now, that second thing you
(16:05):
said is fascinating. So his ability to make memories is compromised.
And it's not just that now he can't remember what
he had for breakfast, can't remember, you know, what he
did yesterday. He also can't imagine what tomorrow will be like.
That's fascinating to me because it means, in some sense,
our ability to remember the past is necessary for our
(16:26):
ability to imagine the future. That forward and backward time
travel are inextricably linked. Yeah, and now something's pointed out
about this patient by Dan Falk and his book In
Search of Time, The History, Physics and Philosophy of Time.
He says that patient Casey is quote completely rooted in
the present, with no ability to move backwards for forward
cognitively in time. And here's the thing too, He's completely
(16:49):
unaware of his condition because he has no no memory,
he cannot form new memories of explanations of what's going
on here, and uh Daniel Shackter, who who wrote the
silent to seven Sins of Memory, which we've referenced on
the show before he had He has said that the
patient Casey is quote, a shell of a person, a fragment,
(17:10):
but also notes that Casey rates his own personal happiness
at a level of four out of five, so he's
he's he's quite happy, He's not in a state of misery.
And you have to, you know, ask to what to
what degree is he happy because he's unshackled from worrying
about the future and contemplating the future or remembering anything
in the past. Yeah, I mean that it's sort of
(17:32):
like asking like, would you like to be like that?
I mean, I think most people probably wouldn't, because you
would still feel that many opportunities for things that you
deeply care about in life are would be closed off
to you if you had this condition, even though the
having the condition might not be all that unpleasant in
the moment. Yeah, I mean, it comes down to that
(17:54):
description of a shell of a person. Would you like
to be a shell of a person who's tremendously happy
all the time? Four out of five, tremendously happy. I mean, well,
I don't know what would you rate yourself, Robert, Uh,
you know what out of well? It vary, you know,
it varies from moment to moment. I guess I would
say four out of five because I wouldn't want to
say five out of five. That's that doesn't leave me
any room for improvement. You could always be happier. Yeah,
(18:17):
But I you know, I I hesitated to give myself
a three. It's a complex question, you know. I hate
to answer well being questions in relation to coffee because
it's such a cliche. But I know mine is in
relation to coffee. It's like when I when I have
had a little bit of coffee, I'm a four. But
when I've had, you know, two cups of coffee, I'm
a two. Oh, because you get you get too jittery,
(18:39):
and I get that, I get the fear. Yeah, it's bad.
I have I have noticed that with my own caffeine consumption,
that the rate is a little different now. In his
book book, Falk also references another individual, a San Diego
resident named ep and he has nearly a nearly identical
condition to patient Casey and Likewise, he has described as
being quote happy all the time, I'm quote and devoid
(19:03):
of a stream of consciousness. He is trapped into present
without the ability to traverse either recorded memory or simulated future.
So this seems to show the same thing that he
his inability to think about events in the past also
prevents him from mentally exploring future events. Um, and I
(19:23):
know I've seen at some point there was a case
where one of these patients was being asked, uh, what
will you do tomorrow? And his answer was whatever is
most beneficial. That's that's that's revealing, like in a way,
he's he's more honest about the He's more honest in
(19:44):
his answer because he's he cannot engage in mental time travel. Right. Well,
if I ask you what you're gonna do tomorrow, you're
gonna kind of bluff a little bit, right, You're gonna say, well,
I'm gonna I think what I'm gonna do is I'm
gonna get up and do my normal stuff, do yoga,
have breakfast, whatever. You're kind of bluffing. You can't really
know that's what you're gonna do. You just think that's
(20:04):
probably what you're gonna do. Right, It's it's ultimately my answer.
It's gonna be just as inevitable as the next Fast
and Furious movie, you know. Um, But obviously many different
things could occur to to drive both of these trains
off the track. I guess the true answer would be
I'm gonna do whatever I do. Yeah. Uh, you know
I mentioned uh Eckartola already. I'm gonna come back to
(20:25):
him one last time in this episode because there's a
wonderful children's book that he put out with Mutt's cartoonist
Patrick McDonald, titled Guardians of Being. And it looks at
our pets, cats and dogs in particular, and it looks
at them as windows into the formless, into the timeless,
the idea that that creatures are bound by neither past
(20:45):
nor present. And this enables us to better center ourselves
in the present. Uh and and and and you actually
reference this a little bit, uh in the first episode
talking about when you when you see the excitement that
your dog has for a walk, right, Well, yeah, yeah,
I mean there's there's like nothing happier in the entire
universe than Charlie about to go outside into the grass.
(21:08):
And uh, and you get the sense I mean probably
probably this is projection, but at least you get the
feeling that this is because it's all there is to
him right now. The only thing in the universe to
him is the thing he's excited about doing, and it's
he's seen all the signals it's about to happen. Like,
he's not worried about anything else. There's nothing else beyond
(21:31):
that thing. There's nothing really behind him. Is just all
about what's about to happen. Yeah, he is. He is
devoid or free from the very human concerns of time.
And indeed this has been a long a long time
understanding of animals that they neither remember the past nor
contemplate the future in a truly meaningful human fashion. Now,
(21:53):
I think that that's a little bit complicated by some
observations of people like, for example, friends of All who
we talk to on the show before um who you know.
He's a primatologist. He studies apes primarily, but he talks
a lot about the intelligence of animals and signs that
he thinks he sees elements of rudimentary time travel in
(22:14):
in some of the great apes and in some birds
and stuff. Right, well, yeah, it does get complimental time travel. Yeah,
I think not actual time. The morlocks did try and
and steal the machine, as I recall. But yeah, if
Falk gets into this a bit in his book, he
he makes a point that that no ape has ever
communicated with sign language anything to suggest he was remembering
(22:36):
a past event. Of course, these sign language by apes
as a way of develving into their mind is also
a complicated situation. Uh. And and there have been studies
with various animals and some birds, uh, mainly primates and
birds that have that have allowed scientists to argue in
favor of mental time travel. But the the argument against
(22:58):
that is, well, to what extent are the do these
anticipations fail to go beyond the context of the present?
So like are they are they is using a tool
to get a meal out of a log? Are you
actually engaging in in mental time travel or are you
just applying a certain uh you know, certain cleverness to
(23:24):
the the situation or is there any difference between the two.
I don't know. I mean, I would say in the
case of apes, I think there are some examples. I
hope I'm not remembering this wrong, but I think I
remember some examples of apes, for example, saving tools for
later that they don't need for a task right now,
but they know can be useful in the future. Or
(23:44):
for example, I think it was Jay's right, Jay's remembering
where items had been placed in a room even though
they couldn't immediately access them. Yeah, these are scrub jays,
I believe, right. Yeah, those those come up in experiments
a lot. So this remains kind of an open question.
There are some some fascinating arguments to be made on
(24:05):
both sides. Uh. As far as humans go, however, human
infants do seem to live in an eternal presence up
until around eight months of age or so, and then
key abilities begin to come online more between three and
five and a six year old child is is just
light years ahead of the smartest chimp or or j
(24:27):
that has ever lived. And uh and this is this
is a fascinating two. Between eight and ten years old,
that's where begin when we begin to see time as
an abstraction. Uh. And another great fact that I ran
across in false book is that most ten year olds
think they age an hour when the clock turns ahead
for daylight savings, but most fifteen year old realize that
(24:49):
that's not the case. I'm kind of surprised about that
with ten year olds. I would think generally ten year
olds would know that, like, the clocks don't determine how
old you are. Well, I wonder how much of the
two is just they're not thinking about that kind of thing,
and if you just spring it on them, they might say, Oh, well,
I guess I am the clocks. The clock when ahead
an hour or so, I'm an hour ahead to Yeah.
But but I found I found that in righted this
idea that we don't have it now, we don't have
(25:11):
a presence, and then our understanding of time just kind
of begins to grow and swell until we can truly
begin to understand the abstraction and just mind rending complexity
of time. All right, well, I think it's time to
turn to some psychology and neuroscience experiments to try to
understand a little bit more about what's going on in
the brain. We've established that physics probably doesn't really allow
(25:33):
for a now, or at least doesn't allow for any
kind of universal simultaneity. There's no externally objective now whether
or not things actually happen, or whether or not time
actually flows in the universe. That's maybe up for debate,
but there's not a universal now, and we still have
this experience of now. So what's going on in the
brain when we have a feeling of the present, when
(25:56):
we say something is happening now, how does the brain
decide what now is? I want to look at a
series of experiments and thoughts associated with the neuroscientist David
Eagleman and many researchers working with Eagleman in his lab.
They've done some really cool stuff with the perception of
simultaneity in the brain. And the first case I want
(26:17):
to look at is the idea of the flash lag experiments. Now, Robert,
have you ever seen these demonstrated or had you know?
Just let this work on your mind a little bit.
I don't think I've actually observed footage of one of
these experiments now, I've only read about them. They're more
They sound very simple when you describe them, but when
you actually notice it happening to you, it's a little
(26:38):
bit troubling. So there are a lot of video demonstrations online.
If you want to see it for yourself, you can
go look up a video of a flash lag experiment.
But I think I can describe it pretty simply here's
one version. Imagine there's a room and in the middle
of the room there's a big vertical hoop, and there
is also a little light that flat that can flash
(26:59):
somewhere in the room. And you see somebody standing at
one end of the room throwing a ball through the air.
And while the ball is in the air, there's a
flash in the video and video of this room, and
you watch it over and over again, Throw flash, throw flash.
And what it looks like to you is that every
time the flash happens uh somewhere in the air after
(27:22):
the ball is about a foot or so past the hoop.
But when the video gets slowed down frame by frame,
you can see clearly that the flash happens at the
exact same time the ball passes through the hoop. And
your brain is getting it wrong. Your brain is lagging
behind events in registering when it sees the flash. So
(27:45):
you might not think this is all that weird, but
it's weirder than it sounds. You're probably thinking, Okay, yeah, Well,
it takes the brain a fraction of a second to
see things like there's a delay between external reality. Um,
and the light has to hit my eyes, my mind
has to process it. But it's weirder than that because
it's not just that you're seeing the entire world or
(28:05):
the whole video at a delay. You're seeing one part
of the video at a delay relative to a different
part of the same video. You're you're perceiving events out
of order, so the flash is lagged relative to the
motion of the ball. It's not just that we don't
see things exactly when they happen. We don't necessarily see
(28:25):
things in the order they happen. And again, this is
this is seeing and perceiving, not remembering, right, Yeah, this
is seeing and perceiving right there in the moment um.
So this effect, and you can show this with all
kinds of different things. Like another version of this would
be you've got a square moving around on a screen,
and when it passes a certain point on the screen,
(28:46):
another square flashes up on the screen for a second,
and you'll be asked to judge the relative positions of
the squares, and you might say, well, the square that
flashes up is I don't know, you know, three or
four grid squares behind the moving square, But in fact
they're exactly in the same place. Like the square that
flashes up flashes up when the other. When the moving
(29:06):
square is exactly in line with it, but you see
it flashing up behind the moving square. Why is this?
Why would your brain be lagging one type of perspective
perception with with relation to the other. This effect has
been known about for at least sixty years. There were
experiments with it in the nineteen fifties and there have
been a bunch of experiments on it since. And before
(29:27):
Eagleman's team first had this paper about this in the
year two thousand, there were two major explanations that have
been hypothesized. One was known as the latent se difference,
and this proposes that the brain processes moving objects faster
than it processes flashed objects. And this assumes quote online
(29:48):
model of visual perception, which essentially means that you are
conscious of perceiving something as soon as the brain can
get the data ready for you. It's all just coming
in as fast as you can see it, and if
it takes longer to get one kind of data ready,
then you just perceive that thing later. You can think
of this sort of like a TV camera that's supplying
(30:09):
a live feed or a live stream, but the feed
is a little bit glitchy, and some types of things
show up on the screen and get pixelated out. It's
basically live, but sometimes things get messed up. The other
main explanation before their paper was motion extrapolation, and this
basically says that perception is predictive. When your brain perceives
(30:30):
a moving object, it compensates for a processing latency by
making you see the object ahead of where it actually
is in its trajectory. So under this model, when you
like see an eagle diving after a rabbit, your brain
actively moves the eagle ahead and its dive to make
up for the processing lag. So it's really about ten
(30:51):
feet from the ground, but your brain says, well, it's
moving pretty fast. Let's make it look like it's seven
feet from the ground to compensate. And then this is
the basic prince of bowl of of of hunting. Right,
you think you're going to aim for where the prey
will be as opposed to where the prey is. Yeah,
but notice in hunting you actually have to aim ahead
of where you see, so your brain isn't fully aiming
(31:12):
ahead for you, like you have to use your hands
and stuff to do that. You can't just aim at
exactly where you see, because that's not actually ahead of
the animal enough to to hit it with the arrow
or whatever. So this version would be kind of like
a live feed, but updated with predictive models of things
that haven't yet taken place in front of the camera.
(31:34):
It would be a predictive, anticipatory camera that says, Okay,
you know this person is moving towards stage left. We'll
just put them a few frames ahead to make up
for the fact that the camera is a little slow. Wow,
I mean it's it sounds like a system that is
in place for a brain that is not not employing
a lot of like conscious thought about the position of
(31:55):
the target. Yeah, yeah, exactly. And I think that's a
really interesting idea. But you can, in iediately see some
reasons for doubting this, and I'll bring up a big
one in a minute. All right, we're gonna take a
quick break, and when we come back, we'll have more
on the science of now and we're back. So in
their two thousand paper, Eagleman and said Snowski proposed an
(32:15):
alternative explanation. It's not either of those. They call their
explanation postdiction quote. Visual awareness is neither predictive nor online,
but instead postdictive. And this means that when you perceive
the flash, happening is retroactively determined by stuff that happens
in a period of time after you see it. I'll
(32:38):
explain why in a second, but they come up with
a period of about eighty milliseconds following the flash. So
in other words, then now you perceive is not a
predictive model of the future like the motion extrapolation hypothesis,
And it's not a slightly glitchy live feed like the
latency difference hypothesis. It's more like a movie. It's more
like a pre taped, edited film home patched together by
(33:01):
your brain, and it happens really fast. It was a
film that was only filmed about eighty milliseconds ago. But
it's not a live feed. It's an edited product. It
kind of it kind of plays into, you know, ideas
of our of our brain, or at least our perception
as being like the pilot in a cockpit, you know,
(33:22):
and uh, and we're given the information we need to
know about what the crew is doing. We're not actually
piloting the starship, but we're just kind of the the
head observer. Yeah, I mean there's a lot in neuroscience
that can kind of create that impression, though that also
gives a rise to the homunculous fallacy inside the brain.
Um But I want to mention a couple of experiments
(33:44):
that they used to back up this hypothesis of postdiction.
So the first experiment tested the motion extrapolation theory and
they found it to be wrong. So the way this
works is you've got a ring going counterclockwise around a screen,
and once it hits a certain spot on the screen,
the screen flashes up an image of a white disk,
(34:05):
and then the ring does one of three things. It
either stops right when the white disc appears, or it
continues along its original path, or it reverses direction and
heads back to the top of the screen. And they said,
to quote what participants report to have seen at the
time of the flash depends on the events after the flash.
(34:27):
So if the ring stops moving right at the time
of the flash, there's no flash lag effect at all.
If our brains were predicting the motion of the ring,
we would probably see a flash lag effect even though
the ring stops moving when the when the disc flashes up.
And then they did another experiment experiment to which further
tested the motion extrapolation theory by having the moving ring
(34:50):
start with the flash, so that the white disk flashes
up as soon as the ring starts moving. The flash
lag effect still showed up even though there was no
original trajector read to predict from. So this seems to,
in my view, pretty much bust the motion prediction theory.
If there's no original trajectory, how could you be predicting right?
(35:10):
So instead, what this seems to indicate is that AFT
is something that happens after we see a flash of
something determines how we integrate the information of the flash.
And this is consistent with other findings in psychology and neuroscience,
for example, that this is really weird one the color
fi effect. Robert, have you ever witnessed this one personally?
(35:32):
I don't think I have. Okay, so very simple set up.
In fact, it's it's so simple it'll sound like it
couldn't be disturbing to you yet again, but it probably
should be. So there's a screen that flashes two dots,
that's all. Dot one appears, then disappears, then Dot two appears,
then disappears. Weirdly enough, under the right conditions, like if
it's happening fast enough, instead of seeing what really happens,
(35:56):
Dot one appears, then disappears, Dot two appears, then disappears.
In said, we perceive a dot moving back and forth
between the positions of the two dots. This is the
plane fi effect. It's the tendency of the brain to
interpret a series of still images as continuous motion. And
of course we we know that this is crucial in film, right. Yeah, well,
(36:19):
I mean this really makes sense when you when you
think about it, right, because we have evolved to perceive
the movement of generally physical objects like a mouse running
across the ground, and then the mouse is not going
to teleport, and therefore, when you have a dot of
light seem to teleport from one spot to another, our
brain is interpreting that as movement from one spot to another.
(36:40):
I think that's a very good explanation. I mean, yeah,
there's no reason to expect we'd see teleportation in nature,
and if we see something that looks like teleportation, it
would make the most sense for the brain to adapt
to that as if it were an error. This This
reminds me too that there have been experiments with very
young children that demonstrate uh that they know that teleportation
has not possible if they see something like teleportation presented
(37:03):
to them, that they know that it's b S. That's cool.
Here's where it gets even weirder. So that's just the
five effects. That's pretty normal, and we can see the
normal explanation for that. It gets weirder when you add
colors to the dots. So it's exact same setup. Dot
one appears than disappears, Dot two appears than disappears, but
make the dots different colors. Dot one is red, dot
(37:27):
two is blue. What people claim to perceive usually in
this experiment is not only a single dot moving between
the two positions, but changing colors halfway along. So dot
one is red, dot two is blue, and you see
it moving to the dot to position and becoming blue
about halfway there. Now, it would seem like this would
(37:50):
only be possible if the brain were retroactively changing the
contents of your present time perception, because if your if
your brain is being pre addictive, if it's thinking ahead,
there would be no way for the brain to predict
the color of the second dot right because you haven't
seen it yet. So the only way you could have.
(38:10):
This illusion is if your brain is retroactively telling you
what you're seeing right now. There you go. There, there's
your now. So the now isn't is starting to look
not so much like a now, The now is starting
to look like a then. So earlier we mentioned that
all this happens to within an eighty millisecond window after
(38:31):
an event. What's the deal with the eighty milliseconds? Well,
in the next couple of experiments, Eagleman and said Snowski
tried to test the latency difference hypothesis. So they put
a came up with a setup similar to the previous experiments.
A ring goes around a screen, A white disk flashes
in the rings path, and then verily, very shortly after that,
the direction of the ring reverses. And essentially they wanted
(38:54):
to see how long the ring had to keep going
in the same direction as it's a original trajectory to
produce the same flash lag effect from the earlier experiments.
If it was just that flashes take a little bit
longer to process than movement, allow the latency difference hypothesis.
They figured that changing the direction of the ring more
than you know, uh ten or twenty milliseconds after the
(39:17):
flash shouldn't change the flash lag impression. Instead, they found
that it did and it lessened it. So any reversal
of the direction of the moving object and before twenty
six milliseconds completely canceled the illusory displacement. And they found
that sixty seven to eighty milliseconds of movement in the
(39:37):
same direction as the original movement are needed to cause
the full flash lag effect. And so their conclusion is
that the flash quote resets motion integration, and motion is
newly calculated and postdicted to the time of the flash.
So what they're saying there their experiments show here is
that flashes get processed a little bit different ly in
(40:00):
the brain than motion does. And when we see a
flashed object, the brain recalculates what we've just seen and
presents it to us. So the first time we're seeing something,
it has already been edited in post kind of a
weird thing to imagine, Like, what does this mean for us?
I would say that in some cases for visual processing,
(40:20):
there is a lag window about eighty milliseconds in which
our brains are still constructing the sense of now, now
isn't happening? Now? Now is happening? At a delay, and
you're not even getting the full story. So from this,
I wonder if it could reasonably said be said that
the human now is not a moment in reality, but
first of all, a perceptual impression. It's sort of a
(40:43):
sketch edited together by the brain, not necessarily reflecting the
order in which events occurred, as might be measured by
a camera or a machine, reflecting an information gathering period
of roughly eighty milliseconds, and with variable editing, editing a
facts depending on what happened during those eighty milliseconds. And
(41:04):
this brings us, I mean, it just brings us back
to the the idea of the cave. Right, we're just
watching the silhouettes on the wall. But the way I
put it is this, we already know that our memories
are not perfect copies of events as they took place. Right.
We've talked about this on the show lots of times.
Our memories are very low resolution, very suggestible. We tend
to change our memories without realizing it all the time.
(41:26):
You just memory is not that good for lots of
kinds of things. But what this suggests is even the
first time you see something, it is in a way
already like a memory. It's as if there is no
such thing as seeing in the real time. Even when
you think you're seeing something right now, it is already
(41:47):
a kind of a constructed memory. Yeah, so many analogies
I'm tempted to like to run to to explain this. Uh,
they all have to They all hinge on the idea
that what we were seeing we're really see you know.
It's like the one that came to mind was, it's
like if we're all going through life seeing through a periscope,
(42:07):
you know, and so we're not really seeing out of
our eyes, you know. Yeah, i'd have to be like
a computerized periscope. It's like making some editing decisions about
what passes through and stuff like that. Um, I mean,
this would I think cause us to to be a
little more cautious about even like, even if you're aware
(42:28):
that you should be conscious of the fallibility of your
own memory, and you know, if you were going to
testify in a court case, you shouldn't be like, you know,
I'm absolutely sure that what happened here is you know, X, Y,
and Z, because your memory is a little bit more
fallible than you think it is. Probably, But even your
perception of events you just now saw just a second
(42:49):
ago is maybe a little more accurate maybe, but still
could have flaws in it. Even though you think you
just saw something, it's not necessarily how it was, especially
if it happened fast. Legal experts will have to chime
in and let us know if if this has actually
been used, because we know that the foulibility of memory
has come up in trial cases before. But but I
(43:12):
wonder if anyone has just brought up, as has brought up,
just how fallible even first impressions may be. I mean,
I wonder by the time you get into a chord,
it's always going to be a memory. But this might
apply to like, say, uh, impressions from the moment, like
if you immediately if you saw something and then immediately
wrote down what you saw or told somebody else what
you saw right then, Um, that that could maybe apply
(43:33):
to that. Yeah, there's a place where things get even weirder.
In a two thousand six paper published in Neurons, Stetson, Qui, Montague,
and Eagleman found that you could actually manipulate this effect,
the flash lag effect, to cause people to question their
own causal role in real time actions. Here's how it
(43:54):
went down. So the team had research subjects press a
key to make a light flash. Pretty pretty simple, right,
you press the key, the light comes up, But the
light didn't flash immediately. There's a time lag between the
key press and the flash. And because we're so adaptable
and so crafty and and and such great little critters,
our brains just started to say, Okay, we've noticed that
(44:16):
there's a lag every time between when you press the
key and the light comes up, so we're just going
to start to ignore that. People started to perceive that
the light was flashing as soon as the button was pressed.
Then the researchers did the really devious thing. They cut
out the delay after this adaptation period had taken place.
(44:38):
And what did the subjects perceive then, Well, because of
their adapted perception, sort of updating the speed of the
flash perception, some of them started to think the light
was flashing before they pressed the key. You know, I
feel like I almost felt this effect when my work
computer was updated most recently, because it got to where
(44:58):
it was so slow, and it was there's a certain
amount of lag time opening programs and sometimes even even typing,
especially in a browser. And then everything was suddenly so fast.
It was almost as if the words were appearing on
the screen before I tied them, almost but not quite. Yeah, well,
I mean one has to wonder that what would you
start to feel if you genuinely believed that it was
(45:21):
possible that the words were appearing on the screen before
you typed them. Well, actually, that's you know what, I guess.
I tend not I'd tend not to think of it
in these terms. But when one enters a like a
real flow state of writing, it's it's almost like that.
And I can and certainly there have been writers before
(45:42):
who claim a sort of uh, you know, muse inspiration
or something, or the idea that something is writing through them.
And I could see where where where it would where
that situation would lend itself to such an interpretation. Right,
You're probably never genuinely confused about what the words where
the words are coming from. But if you work hape
a bowl of being genuinely confused about that, that could
(46:02):
lead to really interesting states of mind. And so there's
a good New Yorker piece from two thousand eleven about
Eagleman actually, and it discusses his hypothesis at the time
that this very phenomenon could be one of the causes
of auditory hallucinations in people with schizophrenia. Uh So this
came to light when Eagleman discovered that people with schizophrenia
(46:22):
tended to be very inaccurate on these types of timing tests.
And so, to quote from the article quote, the voices
in their heads he suspected were no different from anyone
else's internal monologues. Their brains just processed them a little
out of sequence so that the thoughts seemed to belong
to someone else. And then a quote from Eagleman, all
(46:46):
it takes is this tiny tweak in the brain, this
tiny change in perception, and what you see as real
isn't real to anyone else. So, yeah, I mean that's
a fascinating question. Could schizophrenia or any kind of hallucinatory
condition possibly becaused not by uh, you know, not by
all the normal mechanisms, but by malfunctions in our constructed
(47:08):
sense of now? Is your is your feeling of now,
your period of now causation with relationship to the rest
of time and the universe, crucial for your sense of
agency and self. Yeah, and you can easily imagine too,
like the the feeling of that you did something before
you could consciously decide to do it, and what that
(47:29):
would do to your you know, it doesn't take take
much of a supernatural worldview lane over that to create
you know, all matter of demons, and because we now
know from Eagleman's experiments, if they are you know, if
the interpretation of them is correct, that your sense of
what's happening in the moment right now is that is postdicted,
is reconstructed over a very short period of the past,
(47:52):
then you can very well see that happening like you
do actually to decide to do something, but eighty milliseconds
later you have of the impression that you did not
decide to do it, that it just happened. On the
plus side, if there's anything to this hypothesis, and I
don't know how widely this would be taken seriously by
you know, psychiatrists in the field, they might say, you know,
(48:13):
there are a lot of reasons not to agree with that.
But if there's anything to the schizophrenia hypothesis, I think
one positive takeaway could be that timing conditioning therapies could
possibly have success in giving people with these kind of
conditions relief from some of their symptoms. One last thing
about the experience of now from Eagleman's research. Uh, there's
that classic adage. You know that if you were spending
(48:33):
a minute with your favorite friend or something, the time
passes so fast. But then when your hand, when your
hand is caught in a hot wolf trap, time passes
very slowly. Eagleman did not find evidence that the duration
of perception actually changes in the moment, but he did
find evidence that the duration of certain types of experiences
did change upon recollection. So the length of now varies
(48:57):
drastically when you're remembering events in your episodic memory. Uh.
And he thinks this depends largely on the salient novelty
of events we experience. So, for example, a simple experiment,
if you show somebody a flashing pattern on a screen,
any initial change in the pattern gets remembered as lasting
(49:18):
longer than the repeated iterations of a familiar pattern. So
take that very simple example and apply that to your life.
I think you might immediately see that, oh yeah, that
does kind of happen. Like even if all events last
the same amount of time in the moment when they're
measured objectively, instances that introduce novelty to your consciousness tend
(49:42):
to get stretched out in your memory. Retrospectively, this would
mean we could kind of extend our lives by filling
them with change and novelty. Yeah, I mean, this is
the reason one should travel, one should go on vacations.
One should try new things, even even if you're not
actually try having to do them. You know, go go
(50:02):
try mini golf if you've never tried mini golf, because
it seems to stretch your your experience of life out
out even further. Well, I mean I noticed this with
um respect to like, uh, reading and watching movies and
so just any kind of media. Like if I'm re
experiencing something familiar, that experience kind of disappears in the
(50:27):
memory hole, you know. But when I'm experiencing something new
in media, watching a new movie for the first time,
reading a new book for the first time, I'm uh,
that experience gets expanded in memory, like it fills up
more time. It seems like my life was lasting longer
in the moment. This is why one should also go
out of their way to see experimental films that are
(50:49):
both novel and boring, because the combined energy, like you'll
remember that experience for the rest of your life. It
was only it was only a two hour him about
a person setting in a room, but it felt so
much longer. Yeah, so I like this. If so, here's
one of the takeaways about the experience of the present
and now. If you want, if if you're Roy Batty
(51:11):
and you want to have more life, always try something new. Yeah.
That was Roy's problem, is that all he did was saying,
is that you know, he had to turn to violence.
He should have turned to art and travel. I guess
he did turn to travel a little bit. He's seen
that most of us, uh, you know, wouldn't believe, but
you'd think that all those those sea beams glittering in
the in the starlight or whatever, that would have He
(51:34):
sure did talk about it a lot. Yeah, you know,
so it made an impression. Yeah, you know, it reminds
me of I came across this quote recently, um by
Staring Carcer Guard that, uh he said life must be
lived forward, but can only be understood backward. And I
think maybe that's the same way with the present, right,
Like you can't really catch the present, you can't catch
(51:56):
the present in in a backward looking way. You can
only sort of open, have an openness to experiencing the
present going forward. That's the only way to do it
in the moment. But the only way you can really
understand the significance of the moments, the little present now
is in your life is looking back on them with memory. Alright, Well,
on that note, we're gonna wrap it up. But again,
(52:19):
there there's so much that came up in this two
part discussion of now and time. Uh, so much that
we we can and should revisit in future episodes. So
obviously let us know about any particular points of diversion
that you would you would like us to return to
in the meantime. Check out our homepage that's Stuff to
Blow your Mind dot com. That's where we'll find all
(52:41):
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stuff works dot com for more on this and thousands
(53:30):
of other topics. Does it how stuff works dot com
Welcome to Stuff to Blow Your Mind from how Stuff
Works dot com. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb and I'm Joe McCormick, and
we're back for part two of our discussion of this
present moment, the now, and we're trying to get inside
(00:23):
the now. So in our last episode we talked some
about the physics of now, but the history of time
keeping and about the physical concept of now, of the present,
and whether there is such a thing as now. Now.
We're going to keep doing this, probably accidentally several time
and now all the time, but physicists in general would
(00:44):
probably say that there is no such thing as now
from a universal point of view, that relativity shows us
that there isn't simultaneity across the universe, and there's no
external objective way to to sort synchronize events into and
now in the timeline of the universe right and and similarly,
(01:06):
you can't say I'm gonna do x uh eight now's
from right now. It just doesn't work. Yeah, there's no
apparent unit of now in in physical time keeping either.
But physics aside, we still do have this profound sense
of the present. I mean there's a reason these concepts
appear in our language. Why do we have a word
for now? Why do we have a word for the
(01:27):
present if there isn't something relevant going on there? So
this time we wanted to explore the philosophy of the present,
the philosophy of now, and the psychology and neuroscience of now.
What's going on in our minds when we perceive a
present moment, when we think about what's happening right now?
You know, I know I've mentioned New age and spiritual
(01:48):
author Eckart Tootle on the show before and how I
found some of his ideas concerning mindfulness rather helpful. Uh,
And what his central thesis is that the present is
is all we have and this too, being part of
time is an illusion. Oh great, so we've got nothing, Well,
you've got, but there's a lot to be had and nothing.
(02:08):
Here's here's a quote from totally. He says, quote time
isn't precious at all because it is an illusion. What
you perceive as precious is not time. But the one
point that is out of time the now. And I
really like that the idea that maybe we shouldn't think
of now as a point within time, but a point
(02:29):
outside of time. Yeah, I kind of like that too.
I think it might be easy for, you know, some
kind of hard science minded people to think of that
as like, oh, that's just new age nonsense, that doesn't
mean anything. I think that kind of does mean something.
I mean, think about your experience of time. What do
you have the power to act on in your own experience? Like,
(02:53):
what point of time do you have the power to
do something about. You can't really do anything about the
past past, because it's already happened. You can remember it,
but you can't change it except in your memory by
distorting it. And don't underestimate the power of that. No,
that can happen, but you can't actually change what happened
in reality. You can change your memory, but the past
(03:13):
is gone. You can't really change the future because it's
not here yet. You don't have access to it. Right,
So it's you know, you don't have any power over
things that are causally disconnected from you down the chain,
And in a weird way, you almost don't really have
the power to change the present either, because it's happening.
That's right, it's happening right now, at least as you
(03:34):
sense it. I mean, to whatever extent there is such
a thing as the present in our experience, it's what
you're experiencing, not really what you're doing. So where where
do you live? Where does action happen? Where does change
take place? Yeah? Is it? To what extent? Is it?
Is it a conscious thing? Is it is? It? Is?
It's subconscious? Is it a series of subconscious processes that
(03:56):
are going on? Are we all as as our friend, uh,
Scott Baker who put it, Are we all just slaves
to the darkness that comes before and therefore there's no
there's no real choice or or or agency at all. Well,
I'd say that I think our Scott Baker and Eckhart
total are on exactly the same page here that it's
just a question of whether you make it sound positive
(04:17):
or make it sound negative. I never thought of that before. Now,
wouldn't you kind of agree? Yeah? Yeah, I think there's
a valid point. Yeah, Uh, totally is just totally is
selling a a more positive vision of what the world
can be, um and uh and Baker baman not. That's
not to say that Baker doesn't have some optimistic ideas
in mind, but he has a much darker vision of
(04:39):
of of reality of course, and this we're already getting
into the realm of philosophy, right, and there is a
heck of a lot of philosophy of time out there.
Oh yes, yes, yeah, I mean the nature of the
present moment is it's tied up with our experience of reality.
So it is of course the domain of philosophy. It's
one of the most argued about topics in all the philosophy.
(05:00):
You have multiple different schools of thought that weigh in
on the nature of now and time and the place
of time, of now in time, and we could we
could podcast until the end of time about just the
various approaches to this. Yeah. I would say one reason
that philosophy of time is so popular is because it's
so closely related to the philosophy of the perception of
(05:22):
free will. Um. This came up actually just a minute ago,
and what I was talking about comparing you know, our
Scott Baker and Eckartley. In both cases, I think they
might be add I don't want to speak too much
for totally, but I think in both cases it sounds
like they're advocating a universe in which we just kind
of accept that we are not necessarily the causal agents
(05:43):
ourselves that bring about change. That we have the experience,
you know, sort of the sensation of being behind our
own actions. But you can't get behind the behind the actions.
You know that that you as you are acting now
or a product of things that came before, and though
those consequences that came before, we'll have consequences that echo
(06:03):
into the future. But you don't necessarily have free will
in the classical sense under this understanding of time, because
where would the free will take place? What would happen?
What changes in the now? Alright, So so let's just
roll through some of the broad categories of philosophy of
time and the now, uh, and and again again. Each
(06:24):
of these is a topic that we could easily do
an entire podcast episode on and and maybe very well
returned to in the future. So first up, we have
to touch on fatalism. My favorite. This is the notion
to him that the future is unavoidable. With enough data,
or perhaps a robust enough simulation, you could accurately predict
all future events. What's more, you wouldn't be able to
(06:45):
avoid those events. The future is not open, but rit
closed in inexorable, and this entails a good bit more
than the present, but we'll see how it all ties in. Shortly,
I would say that this point of view and my
experience is more popular with physicist than it is with philosophers,
because a lot of philosophers, I think, are are caught
up in the idea of explaining agency, like they're really
(07:07):
trying to find free will and agency and our actions.
But you know, physicists just say, well, look at what
the math says. It looks. You know, every indication from
our mathematical model of the universe is that past and
present and future they're all just part of the same block.
And that's a block of the universe that exists. So
(07:27):
what how how could you change it? In what sense
would you be altering the future? Up next, we have
a reductionism with respect to time. So the idea here
is that time does not exist independently of the events
that occur in time. When we talk about time, we're
talking about temporal relations among things and events. And this
was an argument of Aristotle and many others. So where
(07:50):
do you think this would fit into our idea of
modern physics? It seems like modern physics except for the
people who don't believe in time like you know, Julian
Barber and all those. Most modern physicists would probably not
agree with this, would you say, because spacetime is spacetime? Yeah, yeah,
I would think so. Up next, we have platonism, as
in Plato with respect to time, Plato, Newton, and others.
(08:13):
They counter reductionism with respect to time. The general ideas
there with the idea that time is the independent container
in which all else is stored. Okay, so this sounds
a little bit more like the spacetime idea, like spacetime
could exist without the objects in it. Maybe. Yeah. Now
this next one is a doozy and it takes us
(08:33):
all the way up to Uh. This is mc taggart's argument,
which he made in his work The Unreality of Time. J. N. E.
McTaggart argued that there is no such thing as time.
He argued that there are two ways to order time,
A series in which we measure everything by its relation
to the present, and B series, in which we measure
(08:55):
things by the relationship between two moments in time. Each
one comes with it share of complications and Nictaggart believes
that time containing both A and B series is not real,
but other thinkers have come along to accept either A
or B rather than reject time itself. So this is
sort of asking the question of whether time actually flows, like,
(09:15):
is there such a thing as the present? Is there
happening in the universe? And if things really do happen,
that would seem to be the A series, Right. If
if there's a present moment moving along through the history
of the universe, that that's the A series, and the
B series would be that time is just a It's
just a measurement between change events, right, So that the
(09:37):
subset here people who latch onto A or B A
theory is that is that A series is all there
is and anything that looks like B is really A.
In other words, time passes yet a past a present
in the future. This is also referred to as the
tensed view of time. And you have B theory, which
this say is B is all there is, anything that
(09:58):
looks like A is actually be and time time does
not pass the tense less theory of right. You know,
we talked about this, and I think maybe we should
come back in the future outside of this discussion of
the present moment and now to do a whole episode
on the idea that time doesn't exist, because I think
this is not a majority viewpoint among physicists. You know,
the majority physicists might say nothing actually happens. There is
(10:20):
no present moment in the universe, but there is a
time in the universe. Right. It's it's such a mind
blowing topic that we we do need more time to
consider it, and we will come back to it at
a future point in time. Right, that's when we'll discuss
that there's no such thing as time. Of course, it's
all an illusion. But yeah, so hopefully then we can
(10:41):
talk about Julian Barber and McTaggart and the others who
agree with them. Alright, So moving along with the sort
of broad schools of the philosophy of time, we have
a present is um. This is an a theorist approach
that states that only the present exists. Things outside of
the present. So the claw source of roads, Genghis Khan,
(11:02):
or the next Fast and Furious movie does not exist.
They just literally are not real until they are currently existing. Right.
If it's not currently existing, it's not a thing, be
it Genghis Khan or or or a movie that is
inevitable but not yet made. So the only thing that
(11:23):
exists is the present moment, and the past and the
future are not real and do not exist. Uh yeah,
that seems like it would be hard to make sense
of for me, It would be hard to make sense
of that picture of the universe given um, given like
the lack of simultaneity you know, across the universe and
the fact that things can appear out of order to
(11:44):
different observers based on the speed of light and all that,
right exactly, so, we have another another argument that might
work better with all that, and that is eternalism. This
is one of several non presidentism approaches, and it argues
that objects from the past and future exist. We can
call these non present objects. They exist just as much
(12:05):
as present objects. So the Clossus of Roads and Genghis
Khan exist just as much as you and I, even
if they are no longer present. And here's the other thing,
the inevitable next the Fast and the Furious movie is
much the same. It's as real as anything that's around
right now or existed in the past. But that's only
because it's actually going to happen. It's not like hypothetical
(12:27):
future things that never actually happen exist right now. Well,
that's the thing, it's ultimately hypothetical because something could occur,
or a series of things that could occur that would
obviously prevent the next Fast and Furious movie from happening.
But in that case it never would have existed to
begin with. Yeah, I mean, I mean, I would say
under this model, only the future that actually happens to
(12:49):
come to exist exists right now. But of course we
never got another Interspace movie, we know when we never
got to explore future um miniaturized adventures inside of Martin
short stomach. Oh but we will because Hollywood will continue
to be out of ideas for new things, and they
will just revisit old franchises until they're plowing into like
(13:11):
Police Academy reboots and stuff, and they've got to get
to Interspace two before they do the Police Academy reboot.
All right, well, I look forward to Interspace too, even
if I'm ultimately disappointed at how overwhelming the c g
I is. Alright, Beyond this, we have the growing Block
Universe theory of time. This is an anti presidentism approach
in which the universe is continually getting bigger because of
(13:33):
all this stuff we keep adding. So we're you know,
we're front loading time with new time, new stuff, new
space time. So every second that exists, we're essentially adding
a room onto the house because there's more for the
universe to contain since it contains past and present. Okay,
and then just a one added note on time travel
that I thought was interesting. So time travel cannot happen
(13:55):
in an eighth theory theorist president is um because the
present is all their is, so you can't travel into
the future of the past. Uh. And of course you know,
in addition to all the backward this is an addition
to all the backward causation is impossible talk, which is
all fruit for another discussion. Yeah, well, I think backward
time travel is also impossible under b theory, right. Yeah, well,
(14:18):
I mean I would say that that that is my
understanding as well. But we're really overdue too for a
proper time travel discussion on this show. Yeah, well, I
think we should take a quick break and when we
come back, we will start to look at the psychology
and neuroscience of our experience of now, what what happens
to the mind on the present moment? Thank alright, we're back.
(14:40):
So in our previous episode, we talked a little bit
about mental time travel uh in memory and how these
are core to our experience of time as flowing. We
remember what has come before, we anticipate and use mental
time travel or chronasthesia to understand what is going to happen.
And then we have to wonder what what what would
it be like to be un shackled from these I
(15:01):
mean that's kind of cord to a lot of meditative
exercises or even the flow states that we get into
with our our work or our hobbies, like what what
can we do to cut off the default mode network
and no longer worry about the past and the future
and live in the quote unquote present. Well, some answers
to this question can be found in an individual known
(15:24):
to psychologists as Patient K. This is a Toronto resident
who suffered severe brain damage during a motorcycle accident, and
he lost his episodic memory. So it's important to note
here he can still do all the things he learned
to do prior to the accident thanks to his procedural memory. Right, so,
if you lose your ability to make memories, you still
(15:45):
probably remember how to tie your shoes, right, you can't
remember what you had for breakfast? Right. So this guy
can speak, he can play games that he learned previously,
He can navigate his his neighborhood without becoming lost. But
he cannot remember what he did yesterday, and he cannot
acculate on what he's going to do tomorrow. He has
no autobiographical memory at all. Now, that second thing you
(16:05):
said is fascinating. So his ability to make memories is compromised.
And it's not just that now he can't remember what
he had for breakfast, can't remember, you know, what he
did yesterday. He also can't imagine what tomorrow will be like.
That's fascinating to me because it means, in some sense,
our ability to remember the past is necessary for our
(16:26):
ability to imagine the future. That forward and backward time
travel are inextricably linked. Yeah, and now something's pointed out
about this patient by Dan Falk and his book In
Search of Time, The History, Physics and Philosophy of Time.
He says that patient Casey is quote completely rooted in
the present, with no ability to move backwards for forward
cognitively in time. And here's the thing too, He's completely
(16:49):
unaware of his condition because he has no no memory,
he cannot form new memories of explanations of what's going
on here, and uh Daniel Shackter, who who wrote the
silent to seven Sins of Memory, which we've referenced on
the show before he had He has said that the
patient Casey is quote, a shell of a person, a fragment,
(17:10):
but also notes that Casey rates his own personal happiness
at a level of four out of five, so he's
he's he's quite happy, He's not in a state of misery.
And you have to, you know, ask to what to
what degree is he happy because he's unshackled from worrying
about the future and contemplating the future or remembering anything
in the past. Yeah, I mean that it's sort of
(17:32):
like asking like, would you like to be like that?
I mean, I think most people probably wouldn't, because you
would still feel that many opportunities for things that you
deeply care about in life are would be closed off
to you if you had this condition, even though the
having the condition might not be all that unpleasant in
the moment. Yeah, I mean, it comes down to that
(17:54):
description of a shell of a person. Would you like
to be a shell of a person who's tremendously happy
all the time? Four out of five, tremendously happy. I mean, well,
I don't know what would you rate yourself, Robert, Uh,
you know what out of well? It vary, you know,
it varies from moment to moment. I guess I would
say four out of five because I wouldn't want to
say five out of five. That's that doesn't leave me
any room for improvement. You could always be happier. Yeah,
(18:17):
But I you know, I I hesitated to give myself
a three. It's a complex question, you know. I hate
to answer well being questions in relation to coffee because
it's such a cliche. But I know mine is in
relation to coffee. It's like when I when I have
had a little bit of coffee, I'm a four. But
when I've had, you know, two cups of coffee, I'm
a two. Oh, because you get you get too jittery,
(18:39):
and I get that, I get the fear. Yeah, it's bad.
I have I have noticed that with my own caffeine consumption,
that the rate is a little different now. In his
book book, Falk also references another individual, a San Diego
resident named ep and he has nearly a nearly identical
condition to patient Casey and Likewise, he has described as
being quote happy all the time, I'm quote and devoid
(19:03):
of a stream of consciousness. He is trapped into present
without the ability to traverse either recorded memory or simulated future.
So this seems to show the same thing that he
his inability to think about events in the past also
prevents him from mentally exploring future events. Um, and I
(19:23):
know I've seen at some point there was a case
where one of these patients was being asked, uh, what
will you do tomorrow? And his answer was whatever is
most beneficial. That's that's that's revealing, like in a way,
he's he's more honest about the He's more honest in
(19:44):
his answer because he's he cannot engage in mental time travel. Right. Well,
if I ask you what you're gonna do tomorrow, you're
gonna kind of bluff a little bit, right, You're gonna say, well,
I'm gonna I think what I'm gonna do is I'm
gonna get up and do my normal stuff, do yoga,
have breakfast, whatever. You're kind of bluffing. You can't really
know that's what you're gonna do. You just think that's
(20:04):
probably what you're gonna do. Right, It's it's ultimately my answer.
It's gonna be just as inevitable as the next Fast
and Furious movie, you know. Um, But obviously many different
things could occur to to drive both of these trains
off the track. I guess the true answer would be
I'm gonna do whatever I do. Yeah. Uh, you know
I mentioned uh Eckartola already. I'm gonna come back to
(20:25):
him one last time in this episode because there's a
wonderful children's book that he put out with Mutt's cartoonist
Patrick McDonald, titled Guardians of Being. And it looks at
our pets, cats and dogs in particular, and it looks
at them as windows into the formless, into the timeless,
the idea that that creatures are bound by neither past
(20:45):
nor present. And this enables us to better center ourselves
in the present. Uh and and and and you actually
reference this a little bit, uh in the first episode
talking about when you when you see the excitement that
your dog has for a walk, right, Well, yeah, yeah,
I mean there's there's like nothing happier in the entire
universe than Charlie about to go outside into the grass.
(21:08):
And uh, and you get the sense I mean probably
probably this is projection, but at least you get the
feeling that this is because it's all there is to
him right now. The only thing in the universe to
him is the thing he's excited about doing, and it's
he's seen all the signals it's about to happen. Like,
he's not worried about anything else. There's nothing else beyond
(21:31):
that thing. There's nothing really behind him. Is just all
about what's about to happen. Yeah, he is. He is
devoid or free from the very human concerns of time.
And indeed this has been a long a long time
understanding of animals that they neither remember the past nor
contemplate the future in a truly meaningful human fashion. Now,
(21:53):
I think that that's a little bit complicated by some
observations of people like, for example, friends of All who
we talk to on the show before um who you know.
He's a primatologist. He studies apes primarily, but he talks
a lot about the intelligence of animals and signs that
he thinks he sees elements of rudimentary time travel in
(22:14):
in some of the great apes and in some birds
and stuff. Right, well, yeah, it does get complimental time travel. Yeah,
I think not actual time. The morlocks did try and
and steal the machine, as I recall. But yeah, if
Falk gets into this a bit in his book, he
he makes a point that that no ape has ever
communicated with sign language anything to suggest he was remembering
(22:36):
a past event. Of course, these sign language by apes
as a way of develving into their mind is also
a complicated situation. Uh. And and there have been studies
with various animals and some birds, uh, mainly primates and
birds that have that have allowed scientists to argue in
favor of mental time travel. But the the argument against
(22:58):
that is, well, to what extent are the do these
anticipations fail to go beyond the context of the present?
So like are they are they is using a tool
to get a meal out of a log? Are you
actually engaging in in mental time travel or are you
just applying a certain uh you know, certain cleverness to
(23:24):
the the situation or is there any difference between the two.
I don't know. I mean, I would say in the
case of apes, I think there are some examples. I
hope I'm not remembering this wrong, but I think I
remember some examples of apes, for example, saving tools for
later that they don't need for a task right now,
but they know can be useful in the future. Or
(23:44):
for example, I think it was Jay's right, Jay's remembering
where items had been placed in a room even though
they couldn't immediately access them. Yeah, these are scrub jays,
I believe, right. Yeah, those those come up in experiments
a lot. So this remains kind of an open question.
There are some some fascinating arguments to be made on
(24:05):
both sides. Uh. As far as humans go, however, human
infants do seem to live in an eternal presence up
until around eight months of age or so, and then
key abilities begin to come online more between three and
five and a six year old child is is just
light years ahead of the smartest chimp or or j
(24:27):
that has ever lived. And uh and this is this
is a fascinating two. Between eight and ten years old,
that's where begin when we begin to see time as
an abstraction. Uh. And another great fact that I ran
across in false book is that most ten year olds
think they age an hour when the clock turns ahead
for daylight savings, but most fifteen year old realize that
(24:49):
that's not the case. I'm kind of surprised about that
with ten year olds. I would think generally ten year
olds would know that, like, the clocks don't determine how
old you are. Well, I wonder how much of the
two is just they're not thinking about that kind of thing,
and if you just spring it on them, they might say, Oh, well,
I guess I am the clocks. The clock when ahead
an hour or so, I'm an hour ahead to Yeah.
But but I found I found that in righted this
idea that we don't have it now, we don't have
(25:11):
a presence, and then our understanding of time just kind
of begins to grow and swell until we can truly
begin to understand the abstraction and just mind rending complexity
of time. All right, well, I think it's time to
turn to some psychology and neuroscience experiments to try to
understand a little bit more about what's going on in
the brain. We've established that physics probably doesn't really allow
(25:33):
for a now, or at least doesn't allow for any
kind of universal simultaneity. There's no externally objective now whether
or not things actually happen, or whether or not time
actually flows in the universe. That's maybe up for debate,
but there's not a universal now, and we still have
this experience of now. So what's going on in the
brain when we have a feeling of the present, when
(25:56):
we say something is happening now, how does the brain
decide what now is? I want to look at a
series of experiments and thoughts associated with the neuroscientist David
Eagleman and many researchers working with Eagleman in his lab.
They've done some really cool stuff with the perception of
simultaneity in the brain. And the first case I want
(26:17):
to look at is the idea of the flash lag experiments. Now, Robert,
have you ever seen these demonstrated or had you know?
Just let this work on your mind a little bit.
I don't think I've actually observed footage of one of
these experiments now, I've only read about them. They're more
They sound very simple when you describe them, but when
you actually notice it happening to you, it's a little
(26:38):
bit troubling. So there are a lot of video demonstrations online.
If you want to see it for yourself, you can
go look up a video of a flash lag experiment.
But I think I can describe it pretty simply here's
one version. Imagine there's a room and in the middle
of the room there's a big vertical hoop, and there
is also a little light that flat that can flash
(26:59):
somewhere in the room. And you see somebody standing at
one end of the room throwing a ball through the air.
And while the ball is in the air, there's a
flash in the video and video of this room, and
you watch it over and over again, Throw flash, throw flash.
And what it looks like to you is that every
time the flash happens uh somewhere in the air after
(27:22):
the ball is about a foot or so past the hoop.
But when the video gets slowed down frame by frame,
you can see clearly that the flash happens at the
exact same time the ball passes through the hoop. And
your brain is getting it wrong. Your brain is lagging
behind events in registering when it sees the flash. So
(27:45):
you might not think this is all that weird, but
it's weirder than it sounds. You're probably thinking, Okay, yeah, Well,
it takes the brain a fraction of a second to
see things like there's a delay between external reality. Um,
and the light has to hit my eyes, my mind
has to process it. But it's weirder than that because
it's not just that you're seeing the entire world or
(28:05):
the whole video at a delay. You're seeing one part
of the video at a delay relative to a different
part of the same video. You're you're perceiving events out
of order, so the flash is lagged relative to the
motion of the ball. It's not just that we don't
see things exactly when they happen. We don't necessarily see
(28:25):
things in the order they happen. And again, this is
this is seeing and perceiving, not remembering, right, Yeah, this
is seeing and perceiving right there in the moment um.
So this effect, and you can show this with all
kinds of different things. Like another version of this would
be you've got a square moving around on a screen,
and when it passes a certain point on the screen,
(28:46):
another square flashes up on the screen for a second,
and you'll be asked to judge the relative positions of
the squares, and you might say, well, the square that
flashes up is I don't know, you know, three or
four grid squares behind the moving square, But in fact
they're exactly in the same place. Like the square that
flashes up flashes up when the other. When the moving
(29:06):
square is exactly in line with it, but you see
it flashing up behind the moving square. Why is this?
Why would your brain be lagging one type of perspective
perception with with relation to the other. This effect has
been known about for at least sixty years. There were
experiments with it in the nineteen fifties and there have
been a bunch of experiments on it since. And before
(29:27):
Eagleman's team first had this paper about this in the
year two thousand, there were two major explanations that have
been hypothesized. One was known as the latent se difference,
and this proposes that the brain processes moving objects faster
than it processes flashed objects. And this assumes quote online
(29:48):
model of visual perception, which essentially means that you are
conscious of perceiving something as soon as the brain can
get the data ready for you. It's all just coming
in as fast as you can see it, and if
it takes longer to get one kind of data ready,
then you just perceive that thing later. You can think
of this sort of like a TV camera that's supplying
(30:09):
a live feed or a live stream, but the feed
is a little bit glitchy, and some types of things
show up on the screen and get pixelated out. It's
basically live, but sometimes things get messed up. The other
main explanation before their paper was motion extrapolation, and this
basically says that perception is predictive. When your brain perceives
(30:30):
a moving object, it compensates for a processing latency by
making you see the object ahead of where it actually
is in its trajectory. So under this model, when you
like see an eagle diving after a rabbit, your brain
actively moves the eagle ahead and its dive to make
up for the processing lag. So it's really about ten
(30:51):
feet from the ground, but your brain says, well, it's
moving pretty fast. Let's make it look like it's seven
feet from the ground to compensate. And then this is
the basic prince of bowl of of of hunting. Right,
you think you're going to aim for where the prey
will be as opposed to where the prey is. Yeah,
but notice in hunting you actually have to aim ahead
of where you see, so your brain isn't fully aiming
(31:12):
ahead for you, like you have to use your hands
and stuff to do that. You can't just aim at
exactly where you see, because that's not actually ahead of
the animal enough to to hit it with the arrow
or whatever. So this version would be kind of like
a live feed, but updated with predictive models of things
that haven't yet taken place in front of the camera.
(31:34):
It would be a predictive, anticipatory camera that says, Okay,
you know this person is moving towards stage left. We'll
just put them a few frames ahead to make up
for the fact that the camera is a little slow. Wow,
I mean it's it sounds like a system that is
in place for a brain that is not not employing
a lot of like conscious thought about the position of
(31:55):
the target. Yeah, yeah, exactly. And I think that's a
really interesting idea. But you can, in iediately see some
reasons for doubting this, and I'll bring up a big
one in a minute. All right, we're gonna take a
quick break, and when we come back, we'll have more
on the science of now and we're back. So in
their two thousand paper, Eagleman and said Snowski proposed an
(32:15):
alternative explanation. It's not either of those. They call their
explanation postdiction quote. Visual awareness is neither predictive nor online,
but instead postdictive. And this means that when you perceive
the flash, happening is retroactively determined by stuff that happens
in a period of time after you see it. I'll
(32:38):
explain why in a second, but they come up with
a period of about eighty milliseconds following the flash. So
in other words, then now you perceive is not a
predictive model of the future like the motion extrapolation hypothesis,
And it's not a slightly glitchy live feed like the
latency difference hypothesis. It's more like a movie. It's more
like a pre taped, edited film home patched together by
(33:01):
your brain, and it happens really fast. It was a
film that was only filmed about eighty milliseconds ago. But
it's not a live feed. It's an edited product. It
kind of it kind of plays into, you know, ideas
of our of our brain, or at least our perception
as being like the pilot in a cockpit, you know,
(33:22):
and uh, and we're given the information we need to
know about what the crew is doing. We're not actually
piloting the starship, but we're just kind of the the
head observer. Yeah, I mean there's a lot in neuroscience
that can kind of create that impression, though that also
gives a rise to the homunculous fallacy inside the brain.
Um But I want to mention a couple of experiments
(33:44):
that they used to back up this hypothesis of postdiction.
So the first experiment tested the motion extrapolation theory and
they found it to be wrong. So the way this
works is you've got a ring going counterclockwise around a screen,
and once it hits a certain spot on the screen,
the screen flashes up an image of a white disk,
(34:05):
and then the ring does one of three things. It
either stops right when the white disc appears, or it
continues along its original path, or it reverses direction and
heads back to the top of the screen. And they said,
to quote what participants report to have seen at the
time of the flash depends on the events after the flash.
(34:27):
So if the ring stops moving right at the time
of the flash, there's no flash lag effect at all.
If our brains were predicting the motion of the ring,
we would probably see a flash lag effect even though
the ring stops moving when the when the disc flashes up.
And then they did another experiment experiment to which further
tested the motion extrapolation theory by having the moving ring
(34:50):
start with the flash, so that the white disk flashes
up as soon as the ring starts moving. The flash
lag effect still showed up even though there was no
original trajector read to predict from. So this seems to,
in my view, pretty much bust the motion prediction theory.
If there's no original trajectory, how could you be predicting right?
(35:10):
So instead, what this seems to indicate is that AFT
is something that happens after we see a flash of
something determines how we integrate the information of the flash.
And this is consistent with other findings in psychology and neuroscience,
for example, that this is really weird one the color
fi effect. Robert, have you ever witnessed this one personally?
(35:32):
I don't think I have. Okay, so very simple set up.
In fact, it's it's so simple it'll sound like it
couldn't be disturbing to you yet again, but it probably
should be. So there's a screen that flashes two dots,
that's all. Dot one appears, then disappears, then Dot two appears,
then disappears. Weirdly enough, under the right conditions, like if
it's happening fast enough, instead of seeing what really happens,
(35:56):
Dot one appears, then disappears, Dot two appears, then disappears.
In said, we perceive a dot moving back and forth
between the positions of the two dots. This is the
plane fi effect. It's the tendency of the brain to
interpret a series of still images as continuous motion. And
of course we we know that this is crucial in film, right. Yeah, well,
(36:19):
I mean this really makes sense when you when you
think about it, right, because we have evolved to perceive
the movement of generally physical objects like a mouse running
across the ground, and then the mouse is not going
to teleport, and therefore, when you have a dot of
light seem to teleport from one spot to another, our
brain is interpreting that as movement from one spot to another.
(36:40):
I think that's a very good explanation. I mean, yeah,
there's no reason to expect we'd see teleportation in nature,
and if we see something that looks like teleportation, it
would make the most sense for the brain to adapt
to that as if it were an error. This This
reminds me too that there have been experiments with very
young children that demonstrate uh that they know that teleportation
has not possible if they see something like teleportation presented
(37:03):
to them, that they know that it's b S. That's cool.
Here's where it gets even weirder. So that's just the
five effects. That's pretty normal, and we can see the
normal explanation for that. It gets weirder when you add
colors to the dots. So it's exact same setup. Dot
one appears than disappears, Dot two appears than disappears, but
make the dots different colors. Dot one is red, dot
(37:27):
two is blue. What people claim to perceive usually in
this experiment is not only a single dot moving between
the two positions, but changing colors halfway along. So dot
one is red, dot two is blue, and you see
it moving to the dot to position and becoming blue
about halfway there. Now, it would seem like this would
(37:50):
only be possible if the brain were retroactively changing the
contents of your present time perception, because if your if
your brain is being pre addictive, if it's thinking ahead,
there would be no way for the brain to predict
the color of the second dot right because you haven't
seen it yet. So the only way you could have.
(38:10):
This illusion is if your brain is retroactively telling you
what you're seeing right now. There you go. There, there's
your now. So the now isn't is starting to look
not so much like a now, The now is starting
to look like a then. So earlier we mentioned that
all this happens to within an eighty millisecond window after
(38:31):
an event. What's the deal with the eighty milliseconds? Well,
in the next couple of experiments, Eagleman and said Snowski
tried to test the latency difference hypothesis. So they put
a came up with a setup similar to the previous experiments.
A ring goes around a screen, A white disk flashes
in the rings path, and then verily, very shortly after that,
the direction of the ring reverses. And essentially they wanted
(38:54):
to see how long the ring had to keep going
in the same direction as it's a original trajectory to
produce the same flash lag effect from the earlier experiments.
If it was just that flashes take a little bit
longer to process than movement, allow the latency difference hypothesis.
They figured that changing the direction of the ring more
than you know, uh ten or twenty milliseconds after the
(39:17):
flash shouldn't change the flash lag impression. Instead, they found
that it did and it lessened it. So any reversal
of the direction of the moving object and before twenty
six milliseconds completely canceled the illusory displacement. And they found
that sixty seven to eighty milliseconds of movement in the
(39:37):
same direction as the original movement are needed to cause
the full flash lag effect. And so their conclusion is
that the flash quote resets motion integration, and motion is
newly calculated and postdicted to the time of the flash.
So what they're saying there their experiments show here is
that flashes get processed a little bit different ly in
(40:00):
the brain than motion does. And when we see a
flashed object, the brain recalculates what we've just seen and
presents it to us. So the first time we're seeing something,
it has already been edited in post kind of a
weird thing to imagine, Like, what does this mean for us?
I would say that in some cases for visual processing,
(40:20):
there is a lag window about eighty milliseconds in which
our brains are still constructing the sense of now, now
isn't happening? Now? Now is happening? At a delay, and
you're not even getting the full story. So from this,
I wonder if it could reasonably said be said that
the human now is not a moment in reality, but
first of all, a perceptual impression. It's sort of a
(40:43):
sketch edited together by the brain, not necessarily reflecting the
order in which events occurred, as might be measured by
a camera or a machine, reflecting an information gathering period
of roughly eighty milliseconds, and with variable editing, editing a
facts depending on what happened during those eighty milliseconds. And
(41:04):
this brings us, I mean, it just brings us back
to the the idea of the cave. Right, we're just
watching the silhouettes on the wall. But the way I
put it is this, we already know that our memories
are not perfect copies of events as they took place. Right.
We've talked about this on the show lots of times.
Our memories are very low resolution, very suggestible. We tend
to change our memories without realizing it all the time.
(41:26):
You just memory is not that good for lots of
kinds of things. But what this suggests is even the
first time you see something, it is in a way
already like a memory. It's as if there is no
such thing as seeing in the real time. Even when
you think you're seeing something right now, it is already
(41:47):
a kind of a constructed memory. Yeah, so many analogies
I'm tempted to like to run to to explain this. Uh,
they all have to They all hinge on the idea
that what we were seeing we're really see you know.
It's like the one that came to mind was, it's
like if we're all going through life seeing through a periscope,
(42:07):
you know, and so we're not really seeing out of
our eyes, you know. Yeah, i'd have to be like
a computerized periscope. It's like making some editing decisions about
what passes through and stuff like that. Um, I mean,
this would I think cause us to to be a
little more cautious about even like, even if you're aware
(42:28):
that you should be conscious of the fallibility of your
own memory, and you know, if you were going to
testify in a court case, you shouldn't be like, you know,
I'm absolutely sure that what happened here is you know, X, Y,
and Z, because your memory is a little bit more
fallible than you think it is. Probably, But even your
perception of events you just now saw just a second
(42:49):
ago is maybe a little more accurate maybe, but still
could have flaws in it. Even though you think you
just saw something, it's not necessarily how it was, especially
if it happened fast. Legal experts will have to chime
in and let us know if if this has actually
been used, because we know that the foulibility of memory
has come up in trial cases before. But but I
(43:12):
wonder if anyone has just brought up, as has brought up,
just how fallible even first impressions may be. I mean,
I wonder by the time you get into a chord,
it's always going to be a memory. But this might
apply to like, say, uh, impressions from the moment, like
if you immediately if you saw something and then immediately
wrote down what you saw or told somebody else what
you saw right then, Um, that that could maybe apply
(43:33):
to that. Yeah, there's a place where things get even weirder.
In a two thousand six paper published in Neurons, Stetson, Qui, Montague,
and Eagleman found that you could actually manipulate this effect,
the flash lag effect, to cause people to question their
own causal role in real time actions. Here's how it
(43:54):
went down. So the team had research subjects press a
key to make a light flash. Pretty pretty simple, right,
you press the key, the light comes up, But the
light didn't flash immediately. There's a time lag between the
key press and the flash. And because we're so adaptable
and so crafty and and and such great little critters,
our brains just started to say, Okay, we've noticed that
(44:16):
there's a lag every time between when you press the
key and the light comes up, so we're just going
to start to ignore that. People started to perceive that
the light was flashing as soon as the button was pressed.
Then the researchers did the really devious thing. They cut
out the delay after this adaptation period had taken place.
(44:38):
And what did the subjects perceive then, Well, because of
their adapted perception, sort of updating the speed of the
flash perception, some of them started to think the light
was flashing before they pressed the key. You know, I
feel like I almost felt this effect when my work
computer was updated most recently, because it got to where
(44:58):
it was so slow, and it was there's a certain
amount of lag time opening programs and sometimes even even typing,
especially in a browser. And then everything was suddenly so fast.
It was almost as if the words were appearing on
the screen before I tied them, almost but not quite. Yeah, well,
I mean one has to wonder that what would you
start to feel if you genuinely believed that it was
(45:21):
possible that the words were appearing on the screen before
you typed them. Well, actually, that's you know what, I guess.
I tend not I'd tend not to think of it
in these terms. But when one enters a like a
real flow state of writing, it's it's almost like that.
And I can and certainly there have been writers before
(45:42):
who claim a sort of uh, you know, muse inspiration
or something, or the idea that something is writing through them.
And I could see where where where it would where
that situation would lend itself to such an interpretation. Right,
You're probably never genuinely confused about what the words where
the words are coming from. But if you work hape
a bowl of being genuinely confused about that, that could
(46:02):
lead to really interesting states of mind. And so there's
a good New Yorker piece from two thousand eleven about
Eagleman actually, and it discusses his hypothesis at the time
that this very phenomenon could be one of the causes
of auditory hallucinations in people with schizophrenia. Uh So this
came to light when Eagleman discovered that people with schizophrenia
(46:22):
tended to be very inaccurate on these types of timing tests.
And so, to quote from the article quote, the voices
in their heads he suspected were no different from anyone
else's internal monologues. Their brains just processed them a little
out of sequence so that the thoughts seemed to belong
to someone else. And then a quote from Eagleman, all
(46:46):
it takes is this tiny tweak in the brain, this
tiny change in perception, and what you see as real
isn't real to anyone else. So, yeah, I mean that's
a fascinating question. Could schizophrenia or any kind of hallucinatory
condition possibly becaused not by uh, you know, not by
all the normal mechanisms, but by malfunctions in our constructed
(47:08):
sense of now? Is your is your feeling of now,
your period of now causation with relationship to the rest
of time and the universe, crucial for your sense of
agency and self. Yeah, and you can easily imagine too,
like the the feeling of that you did something before
you could consciously decide to do it, and what that
(47:29):
would do to your you know, it doesn't take take
much of a supernatural worldview lane over that to create
you know, all matter of demons, and because we now
know from Eagleman's experiments, if they are you know, if
the interpretation of them is correct, that your sense of
what's happening in the moment right now is that is postdicted,
is reconstructed over a very short period of the past,
(47:52):
then you can very well see that happening like you
do actually to decide to do something, but eighty milliseconds
later you have of the impression that you did not
decide to do it, that it just happened. On the
plus side, if there's anything to this hypothesis, and I
don't know how widely this would be taken seriously by
you know, psychiatrists in the field, they might say, you know,
(48:13):
there are a lot of reasons not to agree with that.
But if there's anything to the schizophrenia hypothesis, I think
one positive takeaway could be that timing conditioning therapies could
possibly have success in giving people with these kind of
conditions relief from some of their symptoms. One last thing
about the experience of now from Eagleman's research. Uh, there's
that classic adage. You know that if you were spending
(48:33):
a minute with your favorite friend or something, the time
passes so fast. But then when your hand, when your
hand is caught in a hot wolf trap, time passes
very slowly. Eagleman did not find evidence that the duration
of perception actually changes in the moment, but he did
find evidence that the duration of certain types of experiences
did change upon recollection. So the length of now varies
(48:57):
drastically when you're remembering events in your episodic memory. Uh.
And he thinks this depends largely on the salient novelty
of events we experience. So, for example, a simple experiment,
if you show somebody a flashing pattern on a screen,
any initial change in the pattern gets remembered as lasting
(49:18):
longer than the repeated iterations of a familiar pattern. So
take that very simple example and apply that to your life.
I think you might immediately see that, oh yeah, that
does kind of happen. Like even if all events last
the same amount of time in the moment when they're
measured objectively, instances that introduce novelty to your consciousness tend
(49:42):
to get stretched out in your memory. Retrospectively, this would
mean we could kind of extend our lives by filling
them with change and novelty. Yeah, I mean, this is
the reason one should travel, one should go on vacations.
One should try new things, even even if you're not
actually try having to do them. You know, go go
(50:02):
try mini golf if you've never tried mini golf, because
it seems to stretch your your experience of life out
out even further. Well, I mean I noticed this with
um respect to like, uh, reading and watching movies and
so just any kind of media. Like if I'm re
experiencing something familiar, that experience kind of disappears in the
(50:27):
memory hole, you know. But when I'm experiencing something new
in media, watching a new movie for the first time,
reading a new book for the first time, I'm uh,
that experience gets expanded in memory, like it fills up
more time. It seems like my life was lasting longer
in the moment. This is why one should also go
out of their way to see experimental films that are
(50:49):
both novel and boring, because the combined energy, like you'll
remember that experience for the rest of your life. It
was only it was only a two hour him about
a person setting in a room, but it felt so
much longer. Yeah, so I like this. If so, here's
one of the takeaways about the experience of the present
and now. If you want, if if you're Roy Batty
(51:11):
and you want to have more life, always try something new. Yeah.
That was Roy's problem, is that all he did was saying,
is that you know, he had to turn to violence.
He should have turned to art and travel. I guess
he did turn to travel a little bit. He's seen
that most of us, uh, you know, wouldn't believe, but
you'd think that all those those sea beams glittering in
the in the starlight or whatever, that would have He
(51:34):
sure did talk about it a lot. Yeah, you know,
so it made an impression. Yeah, you know, it reminds
me of I came across this quote recently, um by
Staring Carcer Guard that, uh he said life must be
lived forward, but can only be understood backward. And I
think maybe that's the same way with the present, right,
Like you can't really catch the present, you can't catch
(51:56):
the present in in a backward looking way. You can
only sort of open, have an openness to experiencing the
present going forward. That's the only way to do it
in the moment. But the only way you can really
understand the significance of the moments, the little present now
is in your life is looking back on them with memory. Alright, Well,
on that note, we're gonna wrap it up. But again,
(52:19):
there there's so much that came up in this two
part discussion of now and time. Uh, so much that
we we can and should revisit in future episodes. So
obviously let us know about any particular points of diversion
that you would you would like us to return to
in the meantime. Check out our homepage that's Stuff to
Blow your Mind dot com. That's where we'll find all
(52:41):
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(53:02):
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(53:30):
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