FTP, name this Greek thinker from Samos with whose theorem right triangle measurements can be found.
He once stopped an animal from being beaten because he said that he heard the voice of a dead friend coming from it, a notion stemming from his doctrine of metempsychosis.  He also taught the appeal to the tetraktys, or golden section, which was supposedly a mystical symbol.  Probably the first to realize Earth was spherical, he taught that the soul was found in the brain.  However, much of the science discovered at his Croton academy was merely credited to him by members of his brotherhood.  FTP, name this Greek thinker from Samos with whose theorem right triangle measurements can be found.
He once stopped an animal from being beaten because he said that he heard the voice of a dead friend coming from it, a notion stemming from his doctrine of metempsychosis.  
Pythagoras