Empedocles

Empedocles

In time, the Ionian influence and the experimental method spread to the mainland of Greece, to Italy, to Sicily. There was once a time when hardly anyone believed in air. They knew about breathing, of course, and they thought the wind was the breath of the gods. But the idea of air as a static, material but invisible substance was unimagined. The first recorded experiment on air was performed by a physician named Empedocles, who flourished around 450 B.C (The experiment was performed in support of a totally erroneous theory of the circulation of the blood, but the idea of performing any experiment to probe Nature is the important innovation).

Some accounts claim Empedocles identified himself as a god. But perhaps it was only that he was so clever that others thought him a god. He believed that light travels very fast, but not infinitely fast. He taught that there was once a much greater variety of living thing on the Earth, but that many races of beings “must have been unable to beget and continue their kind. For in the case of every species that exists, either craft or courage or speed has from the beginning of its existence protected and preserved it”. In this attempt to explain the lovely adaptation of organisms to their environments, Empedocles, like Anaximander and Democritus, clearly anticipated some aspects of Darwin’s great idea of evolution by natural selection.

The ancient Greeks clearly anticipated some aspects of Darwin’s great idea of evolution by natural selection. Image: Bear Color Pencils Sketch Drawing © Megan (Elena)

Empedocles performed his experiment with a household implement people had used for centuries, the so-called clesydra or “water thief”, which was used as a kitchen ladle. A brazen sphere with an open neck and small holes in the bottom, it is filled by immersing it in water. If you pull it out with the neck uncovered, the water pours out of the holes, making a little shower. But if you pull it out properly, with your thumb covering the neck, the water is retained within the sphere until you lift your thumb. If you try to fill it with the neck covered, nothing happens. Some material substance must be in the way of the water. We cannot see such a substance. What could it be? Empedocles argued that it could only be air. A thing we cannot see can exert pressure, can frustrate my wish to fill a vessel with water if I were dumb enough to leave my finger on the neck. Empedocles had discovered the invisible. Air, he thought, must be matter in a form so finely divided that it could not be seen.

Empedocles is said to have died in an apotheotic fit by leaping into the hot lava at the summit calder of the great volcano of Aetna. But Carl Sagan said he sometimes imagined that the scientist merely slipped during a courageous and pioneering venture in observation geophysics.