… the most ingenious toy in the world…

Sophie put all the typed pages from the unknown philosopher back into the cookie tin and put the lid on it. She crawled out of the den and stood for a while looking across the garden. She thought about what happened yesterday. Her mother had teased her about the "love letter" again at breakfast this morning. She walked quickly over to the mailbox to prevent the same thing from happening today. Getting a love letter two days in a row would be doubly embarrassing.

There was another little white envelope! Sophie began to discern a pattern in the deliveries: every afternoon she would find a big brown envelope. While she read the contents, the philosopher would sneak up to the mailbox with another little white envelope.

So now Sophie would be able to find out who he was. If it was a he! She had a good view of the mailbox from her room. If she stood at the window she would see the mysterious philosopher. White envelopes don't just appear out of thin air!

Sophie decided to keep a careful watch the following day. Tomorrow was Friday and she would have the whole weekend ahead of her.

Why is Lego the most ingenious toy in the world?

But she was a dutiful student. Rummaging on the top shelf of her closet, she found a bag full of Lego blocks of all shapes and sizes.

She went up to her room and opened the envelope. There was only one question today, but it was even dumber than the previous three:

For the first time in ages she began to build with them. As she worked, some ideas began to occur to her about the blocks.

For a start, Sophie was not at all sure she agreed that it was. It was years since she had played with the little plastic blocks. Moreover she could not for the life of her see what Lego could possibly have to do with philosophy.

They are easy to assemble, she thought. Even though they are all different, they all fit together. They are also unbreakable. She couldn't ever remember having seen a broken Lego block. All her blocks looked as bright and new as the day they were bought, many years ago. The best thing about them was that with Lego she could construct any kind of object. And then she could separate the blocks and construct something new.

What more could one ask of a toy? Sophie decided that Lego really could be called the most ingenious toy in the world. But what it had to do with philosophy was beyond her.

Her mother signed deeply. She was probably thinking about the white rabbit and the top hat.

She had nearly finished constructing a big doll's house. Much as she hated to admit it, she hadn't had as much fun in ages.

Why did people quit playing when they grew up?

"I'm not playing!" Sophie retorted indignantly, "I'm doing a very complicated philosophical experiment!"

Here I am again, Sophie. Today you are going to hear about the last of the great natural philosophers. His name is Democritus (c. 460-370 B. C.) and he was from the little town of Abdera on the northern Aegean coast.

When Sophie got home from school the following day, there were several more pages for her in a big brown envelope. She took them upstairs to her room. She could not wait to read them, but she had to keep her eye on the mailbox at the same time.

When her mother got home and saw what Sophie had been doing, she blurted out, "What fun! I'm so glad you're not too grown up to play!"

THE ATOM THEORY

Democritus agreed with his predecessors that transformations in nature could not be due to the fact that anything actually "changed." He therefore assumed that everything was built up of tiny invisible blocks, each of which was eternal and immutable. Democritus called these smallest units atoms.

If you were able to answer the question about Lego blocks without difficulty, you should have no problem understanding what this philosopher's project was.

The word "a-tom" means "un-cuttable." For Democritus it was all-important to establish that the constituent parts that everything else was composed of could not be divided indefinitely into smaller parts. If this were possible, they could not be used as blocks. If atoms could eternally be broken down into ever smaller parts, nature would begin to dissolve like constantly diluted soup.

Moreover, nature's blocks had to be eternal -- because nothing can come from nothing. In this, he agreed with Parmenides and the Eleatics. Also, he believed that all atoms were firm and solid. But they could not all be the same. If all atoms were identical, there would still be no satisfactory explanation of how they could combine to form everything from poppies and olive trees to goatskin and human hair.

So now you see what I meant about Lego blocks. They have more or less the same properties as those which Democritus ascribed to atoms. And that is what makes them so much fun to build with. They are first and foremost indivisible. Then they have different shapes and sizes. They are solid and impermeable. They also have "hooks" and "barbs" so that they can be connected to form every conceivable figure. These connections can later be broken again so that new figures can be constructed from the same blocks.

Democritus believed that nature consisted of an unlimited number and variety of atoms. Some were round and smooth, others were irregular and jagged. And precisely because they were so different they could join together into all kinds of different bodies. But however infinite they might be in number and shape, they were all eternal, immutable, and indivisible.

When a body -- a tree or an animal, for instance -- died and disintegrated, the atoms dispersed and could be used again in new bodies. Atoms moved around in space, but because they had "hooks" and "barbs," they could join together to form all the things we see around us.

The fact that they can be used over and over is what has made Lego so popular. Each single Lego block can be part of a truck one day and part of a castle the day after. We could also say that lego blocks are "eternal." Children of today can play with the same blocks their parents played with when they were little.

Today we can establish that Democritus' atom theory was more or less correct. Nature really is built up of different "atoms" that join and separate again. A hydrogen atom in a cell at the end of my nose was once part of an elephant's trunk. A carbon atom in my cardiac muscle was once in the tail of a dinosaur.

We can form things out of clay too, but clay cannot be used over and over, because it can be broken up into smaller and smaller pieces. These tiny pieces can never be joined together again to make something else.

In our own time, however, scientists have discovered that atoms can be broken into smaller "elemental particles." We call these elemental particles protons, neutrons, and electrons. These will possibly some day be broken into even lesser particles. But physicists agree that somewhere along the line there has to be a limit. There has to be a "minimal part" of which nature consists.

Democritus did not have access to modern electronic apparatus. His only proper equipment was his mind. But reason left him no real choice. Once it is accepted that nothing can change, that nothing can come out of nothing, and that nothing is ever lost, then nature must consist of infinitesimal blocks that can join and separate again.

The atom theory also explains our sense perception, thought Democritus. When we sense something, it is due to the movement of atoms in space. When I see the moon, it is because "moon atoms" penetrate my eye.

Democritus did not believe in any "force" or "soul" that could intervene in natural processes. The only things that existed, he believed, were atoms and the void. Since he believed in nothing but material things, we call him a materialist.

According to Democritus, there is no conscious "design" in the movement of atoms. In nature, everything happens quite mechanically. This does not mean that everything happens randomly, for everything obeys the inevitable laws of necessity. Everything that happens has a natural cause, a cause that is inherent in the thing itself. Democritus once said that he would rather discover a new cause of nature than be the King of Persia.

This meant that human beings had no immortal soul, another belief that many people share today. They believe, like Democritus, that "soul" is connected with brain, and that we cannot have any form of consciousness once the brain disintegrates.

But what about the "soul," then? Surely that could not consist of atoms, of material things? Indeed it could. Democritus believed that the soul was made up of special round, smooth "soul atoms." When a human being died, the soul atoms flew in all directions, and could then become part of a new soul formation.

Democritus's atom theory marked the end of Greek natural philosophy for the time being. He agreed with, Her-aclitus that everything in nature "flowed," since Torms come and go. But behind everything that flowed there were some eternal and immutable things that did not flow. Democritus called them atoms.

During her reading Sophie glanced out of the window several times to see whether her mysterious correspondent had turned up at the mailbox. Now she just sat staring down the road, thinking about what she had read. She felt that Democritus's ideas had been so simple and yet so ingenious. He had discovered the real solution to the problem of "basic substance" and "transformation." This problem had been so complicated that philosophers had gone around puzzling over it for generations. And in the end Democritus had solved it on his own by using his common sense.

At the same time Democritus had raised some new questions. For example, he had said that everything happened mechanically. He did not accept that there was any spiritual force in life -- unlike Empedocles and An-axagoras. Democritus also believed that man had no immortal soul.

Sophie could hardly help smiling. It had to be true that nature was built up of small parts that never changed. At the same time Heraclitus was obviously right in thinking that all forms in nature "flow." Because everybody dies, animals die, even a mountain range slowly disintegrates. The point was that the mountain range is made up of tiny indivisible parts that never break up.

Could she be sure of that?

She didn't know. But then she had only just begun the philosophy course.