The first to introduce a thorough-going scepticism among the Greeks was Pyrrho. He was born about 360 B.C., and was originally a painter. He took part in the Indian expedition of Alexander the Great. He left no writings, and we owe our knowledge of his thoughts chiefly to his disciple Timon of Phlius. His philosophy, in common with all post-Aristotelian systems, is purely practical in its outlook. Scepticism, the denial of knowledge, is not posited on account of its speculative interest, but only because Pyrrho sees in it the road to happiness, and the escape from the calamities of life. The proper course of the sage, said Pyrrho, is to ask himself three questions. Firstly, he must ask what things are and how they are constituted; secondly, how we are related to these things; thirdly, what ought to be our attitude towards them. As to what things are, we can only answer that we know nothing. We only know how things appear to us, but of their inner substance we are ignorant. The same thing appears differently to different people, and therefore it is {363} impossible to know which opinion is right. The diversity of opinion among the wise, as well as among the vulgar, proves this. To every assertion the contradictory assertion can be opposed with equally good grounds, and whatever my opinion, the contrary opinion is believed by somebody else who is quite as clever and competent to judge as I am. Opinion we may have, but certainty and knowledge are impossible. Hence our attitude to things (the third question), ought to be complete suspense of judgment. We can be certain of nothing, not even of the most trivial assertions. Therefore we ought never to make any positive statements on any subject. And the Pyrrhonists were careful to import an element of doubt even into the most trifling assertions which they might make in the course of their daily life. They did not say, "it is so," but "it seems so," or "it appears so to me." Every observation would be prefixed with a "perhaps," or "it may be."