The Greeks Were Curious About Matter
Certain philosophers of ancient Greece—Democritus for one—were fascinated by the question: what is matter? You can imagine one of the philosophers saying to his pupils:
“Gentlemen, let us consider a piece of cheese. With a knife we can cut it in two, thus obtaining smaller pieces. We can then cut one of these smaller pieces in two, obtaining still smaller pieces. We can think about repeating this process over and over to get smaller and smaller pieces of cheese. Now can this process be continued without limit, or will a time come when we arrive at the smallest possible piece of cheese? In other words, is there a piece so small that we must have at least that much or none, with no choice in between?”
It is probable that most people who thought about this question at all during the next two thousand years answered the last question in the negative. The prevailing notion was that matter was continuous, with no theoretical limit as to how small a piece of cheese, or anything else, might be.
This concept was humorously expressed by the British mathematician Augustus De Morgan (1806-1871) in these lines:
Great fleas have little fleas upon their backs to bite ’em,
And little fleas have lesser fleas, and so, ad infinitum.