A History of Western Philosophy: And Its Connection with Political and Social Circumstances from the Earliest Times to the Present Day

by Bertrand Russell

First comes scepticism, with the Sophists, leading to a study of how we know rather than to the attempt to acquire fresh knowledge. Then comes, with Socrates, the emphasis on ethics; with Plato, the rejection of the world of sense in favour of the self-created world of pure thought; with Aristotle, the belief in purpose as the fundamental concept in science.