“Substance” always contains the potentiality to realize a specific “form.” We
could say that “substance” always strives toward achieving an innate
potentiality. Every change in nature, according to Aristotle, is a transformation
of substance from the “potential” to the “actual.”
Yes, I’ll explain what I mean, Sophie. See if this funny story helps you. A
sculptor is working on a large block of granite. He hacks away at the formless
block every day. One day a little boy comes by and says, “What are you
looking for?”
“Wait and see,” answers the sculptor. After a few days the little boy
comes back, and now the sculptor has carved a beautiful horse out of the
granite. The boy stares at it in amazement, then he turns to the sculptor and
says, “How did you know it was in there?”
How indeed! In a sense, the sculptor had seen the horse’s form in the
block of granite, because that particular block of granite had the potentiality to
be formed into the shape or a horse. Similarly Aristotle believed that
everything in nature has the potentiality of realizing, or achieving, a specific
“form.”
Let us return to the chicken and the egg. A chicken’s egg has the
potentiality to become a chicken. This does not mean that all chicken’s eggs
become chickens—many of them end up on the breakfast table as fried eggs,
omelettes, or scrambled eggs, without ever having realized their potentiality.
But it is equally obvious that a chicken’s egg cannot become a goose. That
potentiality is not within a chicken’s egg. The “form” of a thing, then, says
something about its limitation as well as its potentiality.
When Aristotle talks about the “substance” and “form” of things, he does
not only refer to living organisms. Just as it is the chicken’s “form” to cackle,
flutter its wings, and lay eggs, it is the form of the stone to fall to the ground.
Just as the chicken cannot help cackling, the stone cannot help falling to the
ground. You can, of course, lift a stone and hurl it high into the air, but
because it is the stone’s nature to fall to the ground, you cannot hurl it to the
moon. (Take care when you perform this experiment, because the stone
might take revenge and find the shortest route back to the earth!)
The Final Cause
Before we leave the subject of all living and dead things having a “form”
that says something about their potential “action,” I must add that Aristotle had
a remarkable view of causality in nature.
Today when we talk about the “cause” of anything, we mean how it
came to happen. The windowpane was smashed because Peter hurled a
stone through it; a shoe is made because the shoemaker sews pieces of
leather together. But Aristotle held that there were different types of cause in
nature. Altogether he named four different causes. It is important to
understand what he meant by what he called the “final cause.”
In the case of window smashing, it is quite reasonable to ask why Peter
threw the stone. We are thus asking what his purpose was. There can be no
doubt that purpose played a role, also, in the matter of the shoe being made.
But Aristotle also took into account a similar “purpose” when considering the
purely lifeless processes in nature. Here’s an example:
Why does it rain, Sophie? You have probably learned at school that it
rains because the moisture in the clouds cools and condenses into raindrops