But they had no reasonable explanation for how these "smallest elements" that were once building blocks in a horse could suddenly whirl together four or five hundred years later and fashion themselves into a completely new horse. Or an elephant or a crocodile, for that matter. Plato's point was that Democritus' atoms never fashioned themselves into an "eledile" or a "crocophant." This was what set his philosophical reflections going.
If you already understand what I am getting at, you may skip this next paragraph. But just in case, I will clarify: You have a box of Lego and you build a Lego horse. You then take it apart and put the blocks back in the box. You cannot expect to make a new horse just by shaking the box. How could Lego blocks of their own accord find each other and become a new horse again? No, you have to rebuild the horse, Sophie. And the reason you can do it is that you have a picture in your mind of what the horse looked like. The Lego horse is made from a model which remains unchanged from horse to horse.
How did you do with the fifty identical cookies? Let us assume that you have dropped in from outer space and have never seen a baker before. You stumble into a tempting bakery--and there you catch sight of fifty identical gingerbread men on a shelf. I imagine you would wonder how they could be exactly alike. It might well be that one of them has an arm missing, another has lost a bit of its head, and a third has a funny bump on its stomach. But after careful thought, you would nevertheless conclude that all gingerbread men have something in common. Although none of them is perfect, you would suspect that they had a common origin. You would realize that all the cookies were formed in the same mold. And what is more, Sophie, you are now seized by the irresistible desire to see this mold. Because clearly, the mold itself must be utter perfection--and in a sense, more beautiful--in comparison with these crude copies.
If you solved this problem all by yourself, you arrived at the philosophical solution in exactly the same way that Plato did.
Like most philosophers, he "dropped in from outer space." (He stood up on the very tip of one of the fine hairs of the rabbit's fur.) He was astonished at the way all natural phenomena could be so alike, and he concluded that it had to be because there are a limited number of forms "behind" everything we see around us. Plato called these forms ideas. Behind every horse, pig, or human being, there is the "idea horse," "idea pig," and "idea human being." (In the same way, the bakery we spoke of can have gingerbread men, gingerbread horses, and gingerbread pigs. Because every self-respecting bakery has more than one mold. But one mold is enough for each type of gingerbread cookie.)
Plato came to the conclusion that there must be a reality behind the "material world." He called this reality the world of ideas; it contained the eternal and immutable "patterns" behind the various phenomena we come across in nature. This remarkable view is known as Plato's theory of ideas.
True Knowledge
I'm sure you've been following me, Sophie dear. But you may be wondering whether Plato was being serious. Did he really believe that forms like these actually existed in a completely different reality?
He probably didn't believe it literally in the same way for all his life, but in some of his dialogues that is certainly how he means to be understood. Let us try to follow his train of thought.
A philosopher, as we have seen, tries to grasp something that is eternal and immutable. It would serve no purpose, for instance, to write a philosophic treatise on the existence of a particular soap bubble. Partly because one would hardly have time to study it in depth before it burst, and partly because it would probably be rather difficult to find a market for a philosophic treatise on something nobody has ever seen, and which only existed for five seconds.
Plato believed that everything we see around us in nature, everything tangible, can be likened to a soap bubble, since nothing that exists in the world of the senses is lasting. We know, of course, that sooner or later every human being and every animal will die and decompose. Even a block of marble changes and gradually disintegrates. (The Acropolis is falling into ruin, Sophie!