## Monday, March 5, 2012

### art picture for the day 2/ Thales of Miletus

This is a 2nd century A.d. copy of a Greek original.  Well, one could certainly be skeptical of whether this gives a genuine picture of what Thales looked like.  There's similar 2nd century Roman copies of Greek originals of Pythagoras, Plato, and even Socrates.  They all look different at least; you wouldn't expect them to look the same!  I might try to find those; finding this picture of Thales sculpture was hard enough!

Thales is credited with lots.  People try to argue against this or that.  One main thing Thales is credited for is logical proof; but, Aristotle is known as the guy to really abstract away the logical proof process that Greek mathematicians were doing for centuries before him.  Well, maybe Thales was doing logical proof in a vague way.  The arithmetic checks of the Egyptians can be considered 'proof' also!

We know some of the 'major' theorems 'proved' by Thales were at least known to the Babylonians - such as the 'all angles in a semi-circle are right angles.'(I've seen this theorem used in solving the Kepler problem; basicaly, Isaac Newton deriving the three Kepler laws from his inverse square law;), the base angles of an isosceles triangle are equal(a main theorem of 'elementary' trigonometry; also, this theorem was called the bridge of asses in Medieval europe because few could prove it . . . even if it is obvious to a Donkey!), and some other much more elementary proofs.  Well, the equal vertical angles is kind of fun.

Thales is also suppose to have calculated the height of the Pyramids(without just hiking up and measuring it), and predicted a solar eclipse which stopped a war and might have saved his ass from getting killed.  Some speculate he used Babylonian astronomical records to make his lucky guess!

One thing may be more certain than anything else; Thales may have been the first after the Greek dark ages(from the period of Troy and Minoa Crete to the Greeks we know; guys like Thales, Pythagoras, Plato, Athens, and Sparta, Archimedes and so on) to travel to the Babylonians and Egyptians, find their mathematical knowledge interesting and bring it back to Greece where people may have been free to do more mathematics than those cultures were since they did their original creative energies.

A last thought about whether Thales did all the things attributed to him; whereas with Pythagoras, there's indications that he made a school and that school of followers attributed everything to him whether he did them or not, there is nothing from the Greeks or anyone else that he didn't do these things.  There's the whole point that Thales 'angles in a semi-circle are right angles' goes back to the Babylonians; but, the point is that Thales proved it logicaly; not just observed and noted it; these are two differnt things. I've seen some pretty good arguements about him using Babylonian astronomical data as remarked already. I give Thales the benefit of the doubt.