forms that, as it were, lay on their own shelf beyond the natural world. On the
contrary, to Aristotle the “forms” were in the things, because they were the
particular characteristics of these things.
So Aristotle disagreed with Plato that the “idea” chicken came before the
chicken. What Aristotle called the “form” chicken is present in every single
chicken as the chicken’s particular set characteristics—for one, that it lays
eggs. The real chicken and the “form” chicken are thus just as inseparable as
body and soul.
And that is really the essence of Aristotle’s criticism of Plato’s theory of
ideas. But you should not ignore the fact that this was a dramatic turn of
thought. The highest degree of reality, in Plato’s theory, was that which we
think with our reason. It was equally apparent to Aristotle that the highest
degree of reality is that which we perceive with our senses. Plato thought that
all the things we see in the natural world were purely reflections of things that
existed in the higher reality of the world of ideas—and thereby in the human
soul. Aristotle thought the opposite: things that are in the human soul were
purely reflections of natural objects. So nature is the real world. According to
Aristotle, Plato was trapped in a mythical world picture in which the human
imagination was confused with the real world.
Aristotle pointed out that nothing exists in consciousness that has not
first been experienced by the senses. Plato would have said that there is
nothing in the natural world that has not first existed in the world of ideas.
Aristotle held that Plato was thus “doubling the number of things.” He
explained a horse by referring to the “idea” horse. But what kind of an
explanation is that, Sophie? Where does the “idea” horse come from, is my
question. Might there not even be a third horse, which the “idea” horse is just
an imitation of?
Aristotle held that all our thoughts and ideas have come into our
consciousness through what we have heard and seen. But we also have an
innate power of reason. We have no innate ideas, as Plato held, but we have
the innate faculty of organizing all sensory impressions into categories and
classes. This is how concepts such as “stone,” “plant,” “animal,” and “human”
arise. Similarly there arise concepts like “horse,” “lobster,” and “canary.”
Aristotle did not deny that humans have innate reason. On the contrary,
it is precisely reason, according to Aristotle, that is man’s most distinguishing
characteristic. But our reason is completely empty until we have sensed
something. So man has no innate “ideas.”
The Form of a Thing Is Its Specific Characteristics
Having come to terms with Plato’s theory of ideas, Aristotle decided that
reality consisted of various separate things that constitute a unity of form and
substance. The “substance” is what things are made of, while the “form” is
each thing’s specific characteristics.
A chicken is fluttering about in front of you, Sophie. The chicken’s “form”
is precisely that it flutters—and that it cackles and lays eggs. So by the “form”
of a chicken, we mean the specific characteristics of its species—or in other
words, what it does. When the chicken dies—and cackles no more—its “form”
ceases to exist. The only thing that remains is the chicken’s “substance”
(sadly enough, Sophie), but then it is no longer a chicken.
As I said earlier, Aristotle was concerned with the changes in nature.