Greek Science after Aristotle

Michael Fowler  UVa Physics


As we mentioned before, Aristotle’s analysis of motion was criticized by Strato (who died around 268 B.C., he is sometimes called Straton), known as “the Physicist” who was the third director of the Lyceum after Aristotle (the founder) and Theophrastus, who was mainly a botanist.

Strato’s career was curiously parallel to Aristotle’s. Recall Aristotle spent twenty years at Plato’s academy before going to Macedonia to be tutor to Alexander, after which Aristotle came back to Athens to found his own “university”, the Lyceum. A few years later, Alexander conquered most of the known world, dividing it into regions with his old friends in charge. In particular, he had his boyhood friend Ptolemy in charge of Egypt, where Alexander founded the new city of Alexandria. Now Strato, after a period of study at the Lyceum, was hired by Ptolemy to tutor his son Ptolemy II Philadelphus (as he became known) in Alexandria. Subsequently Strato returned to Athens where he was in charge of the Lyceum for almost twenty years, until his death.

Strato, like Aristotle, believed in close observation of natural phenomena, but in our particular field of interest here, the study of motion, he observed much more carefully than Aristotle, and realized that falling bodies usually accelerate. He made two important points: rainwater pouring off a corner of a roof is clearly moving faster when it hits the ground than it was when it left the roof, because a continuous stream can be seen to break into drops which then become spread further apart as they fall towards the ground. His second point was that if you drop something to the ground, it lands with a bigger thud if you drop it from a greater height: compare, say, a three foot drop with a one inch drop. One is forced to conclude that falling objects do not usually reach some final speed in a very short time and then fall steadily, which was Aristotle’s picture. Had this line of investigation been pursued further at the Lyceum, we might have saved a thousand years or more, but after Strato the Lyceum concentrated its efforts on literary criticism.