August 19, 2025 • 19 mins
In this engaging little Blue Book No. 39, renowned author Will Durant explores the life and teachings of Aristotle (384-322 B.C.E.), a brilliant Macedonian thinker who was once a student of Plato and later became the mentor of Alexander the Great. While Alexander set out to conquer the world, Aristotle returned to Athens to establish the Lyceum, where he made groundbreaking contributions to biology, logic, literary theory, ethics, and political science. Rejecting the abstract ideals of his teacher Plato, Aristotle focused on the natural world, famously studying the development of the chick embryo. He viewed the universe as a dynamic interplay of matter in motion, with God as its initial driving force. Contrary to the belief that social evils stem from private property, Aristotle argued they arise from the inherent flaws of human nature. He believed that while we find catharsis in tragic theater, real life necessitates a pursuit of balance, reason, dignity, and the golden mean in all aspects. (Pamela Nagami, M.D.)
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Speaker 1 (00:00):
Chapter four of the Story of Aristotle's Philosophy by Will Durant.
This librovox recording is in the public domain recording by
Pamela and Nagami. The organization of science one Greek science
before Aristotle. Socrates, says Renald, gave philosophy to mankind, and
(00:23):
Aristotle gave it science. There was philosophy before Socrates, and
science before Aristotle. And since Socrates, and since Aristotle, philosophy
and science have made i men's advances, But all has
been built upon the foundation which they laid. Before Aristotle,
science was an embryo with him. It was born. Earlier
(00:47):
civilizations than the Greek had made attempts at science. But
so far as we can catch their thought through their
still obscure cuneiform and hieroglyphic script, their science was indistinguishable
from the theology. That is to say, these pre Hellenic peoples
explained every obscure operation in nature by some supernatural agency.
(01:10):
Everywhere there were gods. Apparently it was the Ionian Greeks
who first dared to give natural explanations of cosmic complexities
and mysterious events. They sought in physics the natural causes
of particular incidents, and in philosophy, a natural theory of
the whole. Thal's six forty five fifty b C. The
(01:34):
father of philosophy, was primarily an astronomer, who astonished the
natives of Melitas by informing them that the Sun and stars,
which they were wont to worship as gods, were merely
balls of fire. His pupil, Annixamander six ten to five
forty BC, the first Greek to make astronomic and geographical charts,
(01:58):
believed that the universe had begun as an undifferentiated mass
from which all things had arisen by the separation of opposites,
That astronomic history periodically repeated itself in the evolution and
dissolution of an infinite number of worlds. That the Earth
was at rest in space by a balance of internal
(02:20):
impulsions like Burden's ass that all our planets had once
been fluid, but had been evaporated by the sun. That
life had first been formed in the sea, but had
been driven upon the land by the subsidence of the water.
That of these stranded animals, some had developed the capacity
(02:41):
to breathe air, and had so become the progenitors of
all later land life. That man could not from the
beginning have been what he now was. For if man
on his first appearance had been so helpless at birth
and had required so long an adolescence as in these
later days, he could not possibly have survived. Annexamines, another
(03:06):
Milesian who flourished around four point fifty BC, described the
primeval condition of things as a very rarefied mass gradually
condensing into wind, cloud, water, earth, and stone. The three
forms of matter, gas, liquid, and solid were progressive stages
(03:26):
of condensation. Heat and cold were merely rarefaction and condensation.
Earthquakes were due to the solidification of an originally fluid earth.
Life and soul were one and animating an expansive force
present in everything everywhere. Anexagoris five hundred to four twenty
(03:49):
eight BC, teacher of Pericles, seems to have given a
correct explanation of solar and lunar eclipses. He discovered the
processes of respiration in plants and fishes, and he explained
man's intelligence by the power of manipulation that came when
the forelimbs were freed from the task of locomotion. Heraclitis
(04:14):
five thirty to four seventy b C. Who left wealth
and its cares to live a life of poverty and study.
In the shade of the temple, porticos at Ephesus turned
science from astronomy to earthlier concerns. All things forever flow
and change, he said, Even in the stillest matter, there
(04:35):
is unseen flux and movement. Cosmic history runs in repetitious cycles,
each beginning and ending in fire. Here is one source
of the Stoic and Christian doctrine of last judgment and hell.
Through strife, says Heraclitis, all things arise and pass away.
War is the father and king of all. Some. He
(04:58):
has made gods, and some men, some slaves and some free.
Where there is no strife, there is decay. The mixture
which is not shaken decomposes. In this flux of change
and struggle and selection, only one thing is constant, and
that is law. This order the same for all things.
(05:21):
No one of gods or men has made, but it
always was, and is and shall be. Empedocles, who flourished
around four forty five b C. And sicily developed to
a further stage the idea of evolution. Organs arise not
by design, but by selection. Nature makes many trials and
(05:42):
experiments with organisms combining organs variously. Where the combination fails,
the organism is weeded out. As time goes on, organisms
are more and more intricately and successfully adapted to their surroundings. Finally,
in Lucippus, who flourished also around four forty five PC,
(06:03):
and Democratus four sixty to three sixty master and Pupil
in Thracian Abderah, we get the last stage of pre
Aristotelian science, materialistic deterministic atomism. Everything, says Leucippus, is driven
by necessity. In reality, says Democritus, there are only atoms,
(06:26):
and the void perception is due to the expulsion of
atoms from the object. Upon the sense organ there are
or have been, or will be, an infinite number of worlds.
At every moment, planets are colliding and dying, and new
worlds are rising out of chaos by the selective aggregation
(06:46):
of atoms of similar size and shape. There is no design.
The universe is a machine. This, in dizzy and superficial
summary is the story of Greek science before Aristotle. Its
cruder items can be well forgiven when we consider the
narrow circle of experimental and observational equipment within which these
(07:08):
pioneers were compelled to work. The stagnation of Greek industry
under the incubus of slavery prevented the full development of
these magnificent beginnings, and the rapid complication of political life
and Athens turned the Sophists and Socrates and Plato away
from these physical and biological researches into the vaguer paths
(07:32):
of ethical and political theory. It is one of the
many glories of Aristotle that he was broad and brave
enough to compass and combine these two lines of Greek thought,
the physical and the moral, that, going back beyond his teacher,
he caught again the thread of scientific development in the
pre Socratic Greeks carried on their work with more resolute
(07:56):
detail and more varied observation, and brought together all the
accumulated results in a magnificent body of organized science. Two
Aristotle as a naturalist. If we begin here chronologically with
his physics, we shall be disappointed, for we find that
(08:17):
this treatise is really a metaphysics, an abstruse analysis of matter, motion, space, time, infinity, cause,
and other such ultimate concepts. One of the more lively
Passages is an attack on Democritus's void. There can be
no void or vacuum in nature, says Aristotle, for in
(08:38):
a vacuum, all bodies would fall with equal velocity. This
being impossible, the supposed void turns out to have nothing
in it, an instance at once of Aristotle's very occasional humor,
his addiction to unproved assumptions, and his tendency to disparage
his predecessors in philosophy. It was the habit of our
(09:01):
philosopher to preface his works with historical sketches of previous
contributions to the subject in hand, and to add to
every contribution and annihilating refutation. Aristotle, after the Ottoman manner,
says Bacon, thought he could not reign secure without putting
all his brethren to death. But to this fratricidal menia
(09:26):
we owe much of our knowledge of pre Socratic thought.
For reasons already given, Aristotle's astronomy represents very little advance
upon his predecessors. He rejects the view of Pythagoras sixth
century b c. That the sun is the center of
our system. He prefers to give that honor to the earth.
(09:48):
But the little Treatise on Meteorology is full of brilliant observations,
and even its speculations strike illuminating fire. This is a
cyclic world, says our philosopher. The sun forever evaporates, the sea,
dries up rivers and springs, and transforms at last the
boundless ocean into the barest rock, while conversely, the uplifted
(10:12):
moisture gathered into clouds falls and renews the rivers in
the seas. Everywhere, change goes on imperceptibly but effectively. Egypt
is the work of the Nile, the product of its
deposits through a thousand centuries. Here the sea encroaches upon
the land. There the land reaches out timidly into the sea.
(10:35):
New continents and new oceans rise, Old oceans and old
continents disappear, and all the face of the world is
changed and re changed in a great sistily and diastole
of growth and dissolution. Sometimes these vast effects occur suddenly
and destroy the geological and material bases of civilization and
(10:56):
even of life. Great catastrophes have periodic denuded the earth
and reduced man again to his first beginnings. Like Sisyphus,
civilization has repeatedly neared its snith, only to fall back
into barbarism and begin to coppo its upward travail. Hence
(11:16):
the almost eternal recurrence in civilization after civilization of the
same inventions and discoveries, the same dark ages of slow
economic and cultural accumulation, the same rebirths of learning in
science and art. No doubt, some popular myths are vague
traditions surviving from earlier cultures. So the story of man
(11:41):
runs in a dreary circle because he is not yet
master of the earth that holds him three the foundation
of biology. It is not so with life. As Aristotle
walked wondering through his great zoological Garden, he became convinced
(12:01):
that the infinite variety of life could be arranged in
a continuous series in which each link would be almost
indistinguishable from the next in all respects, whether in structure
or mode of life, or reproduction and rearing, or sensation
and feeling. There are minute gradations and progressions from the
(12:22):
lowest organisms to the highest. At the bottom of the scale,
we can scarcely divide the living from the dead. Nature
makes so gradual a transition from the inanimate to the
animate kingdom, that the boundary lines which separate them are
indistinct and doubtful, and perhaps a degree of life exists
(12:43):
even in the inorganic Again, many species cannot with certainty
be called plants or animals, and as in these lower organisms,
it is almost impossible at times to assign them to
their proper genus and species, so similar are they So
when every order of life, the continuity of gradations and
(13:04):
differences is as remarkable as the diversity of functions and forms.
But in the midst of this bewildering richness of structures,
certain things stand out convincingly. That life has grown steadily
in complexity and empower, that intelligence has progressed in correlation
with complexity of structure and mobility of form. That there
(13:27):
has been an increasing specialization of function and a continuous
centralization of physiological control. Slowly life created for itself a
nervous system and a brain and mind moved resolutely on
towards the mastery of its environment. The remarkable fact here
(13:47):
is that, with all these gradations and similarities leaping to
Aristotle's eyes, he does not come to the theory of evolution.
He rejects Inpedocles doctrine that all organs and organisms are
a survival of the fittest. And Anaxagorus's idea that man
became intelligent by using his hands for manipulation rather than
(14:07):
for movement, Aristotle thinks, on the contrary, that man so
used his hands because he had become intelligent. Indeed, Aristotle
makes as many mistakes as possible for a man who
is founding the science of biology. He thinks, for example,
that the male element and reproduction merely stimulates and quickens.
(14:29):
It does not occur to him what we now know
from experiments in parthenogenesis that the essential function of the
sperm is not so much to fertilize the ovum as
to provide the embryo with the heritable qualities of the
male parent, and so permit the offspring to be a
vigorous variant, a new admixture of two ancestral lines. As
(14:53):
human dissection was not practiced in his time, he is
particularly fertile in physiological errors. He knows nothing of muscles,
not even of their existence. He does not distinguish arteries
from veins. He thinks the brain is an organ for
cooling the blood. He believes, forgivably, that man has more
(15:15):
sutures in the skull than woman. He believes less forgivably
that man has only eight ribs on each side. He
believes incredibly and unforgivably that woman has fewer teeth than man.
Apparently Aristotle's relations with women were of the most amicable kind.
(15:36):
Yet he makes a greater total advance in biology than
any Greek before or after him. He perceives that birds
and reptiles are near allied in structure, that the monkey
is in form intermediate between quadrupeds and man, and once
he boldly declares that man belongs in one group of
(15:58):
animals with the vi viparous quadrupeds our mammals. He remarks
that the soul in infancy is scarcely distinguishable from the
soul of animals. He makes the illuminating observation that diet
often determines the mode of life for of beasts. Some
are gregarious and others solitary. They live in the way
(16:21):
which is best adapted to obtain the food of their choice.
He anticipates Vonbeer's famous law that characters common to the genus,
like eyes and ears, appear in the developing organism before
characters peculiar to its species. Like the formula of the teeth,
or to its individual self, like the final color of
(16:44):
the eyes. And he reaches out across two thousand years
to anticipate Spencer's generalization that individuation varies inversely as genesis,
that is, that the more highly developed and specialized a
species or an individual happens to be, the smaller will
(17:04):
be the number of its offspring. He notices and explains
reversion to type, the tendency of a prominent variation like genius,
to be diluted in mating and lost in successive generations.
He makes many zoological observations, which temporarily rejected by later biologists,
(17:25):
have been confirmed by modern research of fishes that make nests,
for example, and a species of shark that boasts of
a placenta. And finally, he establishes the science of embryology.
He who sees things grow from their beginning, he writes,
will have the finest view of them. Hippocrates born four
(17:47):
sixty BC, greatest of Greek physicians, had given a fine
example of the experimental method by breaking a hen's eggs
at various stages of incubation, and had applied the result
of these studies in his Treatise on the Origin of
the Child. Aristotle followed this lead and performed experiments which
(18:08):
enabled him to give a description of the development of
the chick, which even today arouses the admiration of embryologists.
He must have performed some novel experiments in genetics, for
he disproves the theory that the sex of the child
depends on what testis supplies the reproductive fluid. By quoting
(18:28):
a case where the right tests of the father had
been tied, and yet the children had been of different sexes.
He raises some very modern problems of heredity. A woman
of Ellis had married a Negro. Her children were all whites,
but in the next generation negroes reappeared, Where asks Aristotle,
(18:49):
was the blackness hidden in the middle generation. There was
but a step from such a vital and intelligent query
to the epical experiments of Gregor Mendel eighteen twenty two
to eighteen eighty two, Prudens, Kristio Demidiamski, and Ti. To
know what to ask is already to know half. Surely,
(19:11):
despite the errors that mar these biological works, they formed
the greatest monument ever raised to the science by any
one man. When we consider that before Aristotle there had been,
so far as we know, no biology beyond scattered observations.
We perceived that this achievement alone might have sufficed for
(19:32):
one lifetime, and would have given immortality. But Aristotle had
only begun end of Chapter four
Chapter four of the Story of Aristotle's Philosophy by Will Durant.
This librovox recording is in the public domain recording by
Pamela and Nagami. The organization of science one Greek science
before Aristotle. Socrates, says Renald, gave philosophy to mankind, and
(00:23):
Aristotle gave it science. There was philosophy before Socrates, and
science before Aristotle. And since Socrates, and since Aristotle, philosophy
and science have made i men's advances, But all has
been built upon the foundation which they laid. Before Aristotle,
science was an embryo with him. It was born. Earlier
(00:47):
civilizations than the Greek had made attempts at science. But
so far as we can catch their thought through their
still obscure cuneiform and hieroglyphic script, their science was indistinguishable
from the theology. That is to say, these pre Hellenic peoples
explained every obscure operation in nature by some supernatural agency.
(01:10):
Everywhere there were gods. Apparently it was the Ionian Greeks
who first dared to give natural explanations of cosmic complexities
and mysterious events. They sought in physics the natural causes
of particular incidents, and in philosophy, a natural theory of
the whole. Thal's six forty five fifty b C. The
(01:34):
father of philosophy, was primarily an astronomer, who astonished the
natives of Melitas by informing them that the Sun and stars,
which they were wont to worship as gods, were merely
balls of fire. His pupil, Annixamander six ten to five
forty BC, the first Greek to make astronomic and geographical charts,
(01:58):
believed that the universe had begun as an undifferentiated mass
from which all things had arisen by the separation of opposites,
That astronomic history periodically repeated itself in the evolution and
dissolution of an infinite number of worlds. That the Earth
was at rest in space by a balance of internal
(02:20):
impulsions like Burden's ass that all our planets had once
been fluid, but had been evaporated by the sun. That
life had first been formed in the sea, but had
been driven upon the land by the subsidence of the water.
That of these stranded animals, some had developed the capacity
(02:41):
to breathe air, and had so become the progenitors of
all later land life. That man could not from the
beginning have been what he now was. For if man
on his first appearance had been so helpless at birth
and had required so long an adolescence as in these
later days, he could not possibly have survived. Annexamines, another
(03:06):
Milesian who flourished around four point fifty BC, described the
primeval condition of things as a very rarefied mass gradually
condensing into wind, cloud, water, earth, and stone. The three
forms of matter, gas, liquid, and solid were progressive stages
(03:26):
of condensation. Heat and cold were merely rarefaction and condensation.
Earthquakes were due to the solidification of an originally fluid earth.
Life and soul were one and animating an expansive force
present in everything everywhere. Anexagoris five hundred to four twenty
(03:49):
eight BC, teacher of Pericles, seems to have given a
correct explanation of solar and lunar eclipses. He discovered the
processes of respiration in plants and fishes, and he explained
man's intelligence by the power of manipulation that came when
the forelimbs were freed from the task of locomotion. Heraclitis
(04:14):
five thirty to four seventy b C. Who left wealth
and its cares to live a life of poverty and study.
In the shade of the temple, porticos at Ephesus turned
science from astronomy to earthlier concerns. All things forever flow
and change, he said, Even in the stillest matter, there
(04:35):
is unseen flux and movement. Cosmic history runs in repetitious cycles,
each beginning and ending in fire. Here is one source
of the Stoic and Christian doctrine of last judgment and hell.
Through strife, says Heraclitis, all things arise and pass away.
War is the father and king of all. Some. He
(04:58):
has made gods, and some men, some slaves and some free.
Where there is no strife, there is decay. The mixture
which is not shaken decomposes. In this flux of change
and struggle and selection, only one thing is constant, and
that is law. This order the same for all things.
(05:21):
No one of gods or men has made, but it
always was, and is and shall be. Empedocles, who flourished
around four forty five b C. And sicily developed to
a further stage the idea of evolution. Organs arise not
by design, but by selection. Nature makes many trials and
(05:42):
experiments with organisms combining organs variously. Where the combination fails,
the organism is weeded out. As time goes on, organisms
are more and more intricately and successfully adapted to their surroundings. Finally,
in Lucippus, who flourished also around four forty five PC,
(06:03):
and Democratus four sixty to three sixty master and Pupil
in Thracian Abderah, we get the last stage of pre
Aristotelian science, materialistic deterministic atomism. Everything, says Leucippus, is driven
by necessity. In reality, says Democritus, there are only atoms,
(06:26):
and the void perception is due to the expulsion of
atoms from the object. Upon the sense organ there are
or have been, or will be, an infinite number of worlds.
At every moment, planets are colliding and dying, and new
worlds are rising out of chaos by the selective aggregation
(06:46):
of atoms of similar size and shape. There is no design.
The universe is a machine. This, in dizzy and superficial
summary is the story of Greek science before Aristotle. Its
cruder items can be well forgiven when we consider the
narrow circle of experimental and observational equipment within which these
(07:08):
pioneers were compelled to work. The stagnation of Greek industry
under the incubus of slavery prevented the full development of
these magnificent beginnings, and the rapid complication of political life
and Athens turned the Sophists and Socrates and Plato away
from these physical and biological researches into the vaguer paths
(07:32):
of ethical and political theory. It is one of the
many glories of Aristotle that he was broad and brave
enough to compass and combine these two lines of Greek thought,
the physical and the moral, that, going back beyond his teacher,
he caught again the thread of scientific development in the
pre Socratic Greeks carried on their work with more resolute
(07:56):
detail and more varied observation, and brought together all the
accumulated results in a magnificent body of organized science. Two
Aristotle as a naturalist. If we begin here chronologically with
his physics, we shall be disappointed, for we find that
(08:17):
this treatise is really a metaphysics, an abstruse analysis of matter, motion, space, time, infinity, cause,
and other such ultimate concepts. One of the more lively
Passages is an attack on Democritus's void. There can be
no void or vacuum in nature, says Aristotle, for in
(08:38):
a vacuum, all bodies would fall with equal velocity. This
being impossible, the supposed void turns out to have nothing
in it, an instance at once of Aristotle's very occasional humor,
his addiction to unproved assumptions, and his tendency to disparage
his predecessors in philosophy. It was the habit of our
(09:01):
philosopher to preface his works with historical sketches of previous
contributions to the subject in hand, and to add to
every contribution and annihilating refutation. Aristotle, after the Ottoman manner,
says Bacon, thought he could not reign secure without putting
all his brethren to death. But to this fratricidal menia
(09:26):
we owe much of our knowledge of pre Socratic thought.
For reasons already given, Aristotle's astronomy represents very little advance
upon his predecessors. He rejects the view of Pythagoras sixth
century b c. That the sun is the center of
our system. He prefers to give that honor to the earth.
(09:48):
But the little Treatise on Meteorology is full of brilliant observations,
and even its speculations strike illuminating fire. This is a
cyclic world, says our philosopher. The sun forever evaporates, the sea,
dries up rivers and springs, and transforms at last the
boundless ocean into the barest rock, while conversely, the uplifted
(10:12):
moisture gathered into clouds falls and renews the rivers in
the seas. Everywhere, change goes on imperceptibly but effectively. Egypt
is the work of the Nile, the product of its
deposits through a thousand centuries. Here the sea encroaches upon
the land. There the land reaches out timidly into the sea.
(10:35):
New continents and new oceans rise, Old oceans and old
continents disappear, and all the face of the world is
changed and re changed in a great sistily and diastole
of growth and dissolution. Sometimes these vast effects occur suddenly
and destroy the geological and material bases of civilization and
(10:56):
even of life. Great catastrophes have periodic denuded the earth
and reduced man again to his first beginnings. Like Sisyphus,
civilization has repeatedly neared its snith, only to fall back
into barbarism and begin to coppo its upward travail. Hence
(11:16):
the almost eternal recurrence in civilization after civilization of the
same inventions and discoveries, the same dark ages of slow
economic and cultural accumulation, the same rebirths of learning in
science and art. No doubt, some popular myths are vague
traditions surviving from earlier cultures. So the story of man
(11:41):
runs in a dreary circle because he is not yet
master of the earth that holds him three the foundation
of biology. It is not so with life. As Aristotle
walked wondering through his great zoological Garden, he became convinced
(12:01):
that the infinite variety of life could be arranged in
a continuous series in which each link would be almost
indistinguishable from the next in all respects, whether in structure
or mode of life, or reproduction and rearing, or sensation
and feeling. There are minute gradations and progressions from the
(12:22):
lowest organisms to the highest. At the bottom of the scale,
we can scarcely divide the living from the dead. Nature
makes so gradual a transition from the inanimate to the
animate kingdom, that the boundary lines which separate them are
indistinct and doubtful, and perhaps a degree of life exists
(12:43):
even in the inorganic Again, many species cannot with certainty
be called plants or animals, and as in these lower organisms,
it is almost impossible at times to assign them to
their proper genus and species, so similar are they So
when every order of life, the continuity of gradations and
(13:04):
differences is as remarkable as the diversity of functions and forms.
But in the midst of this bewildering richness of structures,
certain things stand out convincingly. That life has grown steadily
in complexity and empower, that intelligence has progressed in correlation
with complexity of structure and mobility of form. That there
(13:27):
has been an increasing specialization of function and a continuous
centralization of physiological control. Slowly life created for itself a
nervous system and a brain and mind moved resolutely on
towards the mastery of its environment. The remarkable fact here
(13:47):
is that, with all these gradations and similarities leaping to
Aristotle's eyes, he does not come to the theory of evolution.
He rejects Inpedocles doctrine that all organs and organisms are
a survival of the fittest. And Anaxagorus's idea that man
became intelligent by using his hands for manipulation rather than
(14:07):
for movement, Aristotle thinks, on the contrary, that man so
used his hands because he had become intelligent. Indeed, Aristotle
makes as many mistakes as possible for a man who
is founding the science of biology. He thinks, for example,
that the male element and reproduction merely stimulates and quickens.
(14:29):
It does not occur to him what we now know
from experiments in parthenogenesis that the essential function of the
sperm is not so much to fertilize the ovum as
to provide the embryo with the heritable qualities of the
male parent, and so permit the offspring to be a
vigorous variant, a new admixture of two ancestral lines. As
(14:53):
human dissection was not practiced in his time, he is
particularly fertile in physiological errors. He knows nothing of muscles,
not even of their existence. He does not distinguish arteries
from veins. He thinks the brain is an organ for
cooling the blood. He believes, forgivably, that man has more
(15:15):
sutures in the skull than woman. He believes less forgivably
that man has only eight ribs on each side. He
believes incredibly and unforgivably that woman has fewer teeth than man.
Apparently Aristotle's relations with women were of the most amicable kind.
(15:36):
Yet he makes a greater total advance in biology than
any Greek before or after him. He perceives that birds
and reptiles are near allied in structure, that the monkey
is in form intermediate between quadrupeds and man, and once
he boldly declares that man belongs in one group of
(15:58):
animals with the vi viparous quadrupeds our mammals. He remarks
that the soul in infancy is scarcely distinguishable from the
soul of animals. He makes the illuminating observation that diet
often determines the mode of life for of beasts. Some
are gregarious and others solitary. They live in the way
(16:21):
which is best adapted to obtain the food of their choice.
He anticipates Vonbeer's famous law that characters common to the genus,
like eyes and ears, appear in the developing organism before
characters peculiar to its species. Like the formula of the teeth,
or to its individual self, like the final color of
(16:44):
the eyes. And he reaches out across two thousand years
to anticipate Spencer's generalization that individuation varies inversely as genesis,
that is, that the more highly developed and specialized a
species or an individual happens to be, the smaller will
(17:04):
be the number of its offspring. He notices and explains
reversion to type, the tendency of a prominent variation like genius,
to be diluted in mating and lost in successive generations.
He makes many zoological observations, which temporarily rejected by later biologists,
(17:25):
have been confirmed by modern research of fishes that make nests,
for example, and a species of shark that boasts of
a placenta. And finally, he establishes the science of embryology.
He who sees things grow from their beginning, he writes,
will have the finest view of them. Hippocrates born four
(17:47):
sixty BC, greatest of Greek physicians, had given a fine
example of the experimental method by breaking a hen's eggs
at various stages of incubation, and had applied the result
of these studies in his Treatise on the Origin of
the Child. Aristotle followed this lead and performed experiments which
(18:08):
enabled him to give a description of the development of
the chick, which even today arouses the admiration of embryologists.
He must have performed some novel experiments in genetics, for
he disproves the theory that the sex of the child
depends on what testis supplies the reproductive fluid. By quoting
(18:28):
a case where the right tests of the father had
been tied, and yet the children had been of different sexes.
He raises some very modern problems of heredity. A woman
of Ellis had married a Negro. Her children were all whites,
but in the next generation negroes reappeared, Where asks Aristotle,
(18:49):
was the blackness hidden in the middle generation. There was
but a step from such a vital and intelligent query
to the epical experiments of Gregor Mendel eighteen twenty two
to eighteen eighty two, Prudens, Kristio Demidiamski, and Ti. To
know what to ask is already to know half. Surely,
(19:11):
despite the errors that mar these biological works, they formed
the greatest monument ever raised to the science by any
one man. When we consider that before Aristotle there had been,
so far as we know, no biology beyond scattered observations.
We perceived that this achievement alone might have sufficed for
(19:32):
one lifetime, and would have given immortality. But Aristotle had
only begun end of Chapter four
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