Monday, December 19, 2011

Credit where credit is due

From The Dream of Reason by Anthony Gottlieb

Consider ... what [John Philoponus (AD c.490 - c.530)] had to say about Aristotle's assertion that unsupported bodies fall towards the earth with a speed that is proportional to their weight - i.e., that heavy things fall faster than light ones:

But this is completely erroneous, and our view may be corroborated by actual observation more effectively than by any sort of verbal argument. For if you let fall from the same height two weights of which one is many times as heavy as the other, you will see that the ratio of the times required for the motion does not depend on the ration of the weights, but that the difference in time is a very small one.
Philoponus' own theory of falling bodies was not quite right, but the experiment he describes here (which does at least refute Aristotle's view) was heralded as a momentous scientific breakthrough when it was repeated in the seventeenth century. Nowadays the experiment is traditionally credited to Galileo, who lived more than 1,000 years later than Philoponus (and who knew his works well.)

No comments: