Impact. Plato is now best known as the main representative of idealist philosophy in the West and the founder of the Academy, the first Western university. He is far less often recognized, however, as a mathematical philosopher (or philosophical mathematician), even though that is how he might have preferred to describe himself.

Forms. His purely philosophical activity also influenced Greek scientific research, although that influence was certainly a mixed and not always encouraging one. Plato's idealism on the whole tended to devalue the world of the senses as an unstable realm of continual "coming-to-be" and "passing-away." It is but a pale shadow of the real world of the Forms. If the world we perceive is unreal, however, then research into natural phenomena is correspondingly of less value and importance than efforts to comprehend the ideal Forms on which things in...