Greek philosophers
Speusippos
Speusippos was a Greek philosopher and mathematician. He was born in 407 BC (Athens) and died in 339 BC (Athens). He was the nephew of Plato and, after his death, the second head of the Platonic Academy.
Speusippus's teacher was Isocrates, but from him he went to Plato in his Academy. He accompanied him on his third journey to Sicily. On his deathbed, Plato proposed him as his successor and the school approved. Speusippos then led the Academy until his death. He was succeeded by Xenocrates.
Of Speusippus's work, only a fragment of On Pythagorean Numbers survives.
Speusippos distinguished the "One" as the beginning of things, whereas the "Good" comes later. He is said to have had a greater appreciation for the study of nature, especially plants and animals. It may be inferred that he turned to empirical investigation and observation, thus taking a step from philosophy to science.