Pyrrho, along with Anaxarchus, travelled with Alexander the Great on his exploration of the east, and studied in India under the Gymnosophists and under the Magi in Persia. From the Oriental philosophy he seems to have adopted a life of solitude. Returning to Elis, he lived in poor circumstances, but was highly honoured by the Elians and also by the Athenians, who gave him the rights of citizenship. His doctrines are known mainly through the satiric writings of his pupil Timon of Phlius (the Sillographer). The main principle of his thought is expressed in the word acatalepsia, which implies the impossibility of knowing things in their own nature. Against every statement the contradictory may be advanced with equal reason. Secondly, it is necessary in view of this fact to preserve an attitude of intellectual suspense, or, as Timon expressed it, no assertion can be known to be better than another. Thirdly, these results are applied to life in general. Pyrrho concludes that, since nothing can be known, the only proper attitude is ataraxia, "freedom from worry".
The impossibility of knowledge, even in regard to our own ignorance or doubt, should induce the wise man to withdraw into himself, avoiding the stress and emotion which belong to the contest of vain imaginings. This drastic skepticism is the first and the most thorough exposition of agnosticism in the history of thought. Its ethical results may be compared with the ideal tranquillity of the Stoics and the Epicureans.