that are drawn to the earth by the force of gravity. Aristotle would have
nodded in agreement. But he would have added that so far you have only
mentioned three of the causes. The “material cause” is that the moisture (the
clouds) was there at the precise moment when the air cooled. The “efficient
cause” is that the moisture cools, and the “formal cause” is that the “form,” or
nature of the water, is to fall to the earth. But if you stopped there, Aristotle
would add that it rains because plants and animals need rainwater in order to
grow. This he called the “final cause.” Aristotle assigns the raindrops a life-
task, or “purpose.”
We would probably turn the whole thing upside down and say that plants
grow because they find moisture. You can see the difference, can’t you,
Sophie? Aristotle believed that there is a purpose behind everything in nature.
It rains so that plants can grow; oranges and grapes grow so that people can
eat them.
That is not the nature of scientific reasoning today. We say that food and
water are necessary conditions of life for man and beast. Had we not had
these conditions we would not have existed. But it is not the purpose of water
or oranges to be food for us.
In the question of causality then, we are tempted to say that Aristotle
was wrong. But let us not be too hasty. Many people believe that God created
the world as it is so that all His creatures could live in it. Viewed in this way, it
can naturally be claimed that there is water in the rivers because animals and
humans need water to live. But now we are talking about God’s purpose. The
raindrops and the waters of the river have no interest in our welfare.
Logic
The distinction between “form” and “substance” plays an important part
in Aristotle’s explanation of the way we discern things in the world.
When we discern things, we classify them in various groups or
categories. I see a horse, then I see another horse, and another. The horses
are not exactly alike, but they have something in common, and this common
something is the horse’s “form.” Whatever might be distinctive, or individual,
belongs to the horse’s “substance.”
So we go around pigeonholing everything. We put cows in cowsheds,
horses in stables, pigs in pigsties, and chickens in chicken coops. The same
happens when Sophie Amundsen tidies up her room. She puts her books on
the bookshelf, her schoolbooks in her schoolbag, and her magazines in the
drawer. Then she folds her clothes neatly and puts them in the closet—
underwear on one shelf, sweaters on another, and socks in a drawer on their
own. Notice that we do the same thing in our minds. We distinguish between
things made of stone, things made of wool, and things made of rubber. We
distinguish between things that are alive or dead, and we distinguish between
vegetable, animal, and human.
Do you see, Sophie? Aristotle wanted to do a thorough clearing up in
nature’s “room.” He tried to show that everything in nature belongs to different
categories and subcategories. (Hermes is a live creature, more specifically an
animal, more specifically a vertebrate, more specifically a mammal, more
specifically a dog, more specifically a Labrador, more specifically a male
Labrador.)
Go into your room, Sophie. Pick up something, anything, from the floor.