Sayings of Socrates 40

Unlike most philosophers, he had no need to travel, except when required to go on an expedition. The rest of his life he stayed at home and engaged all the more keenly in argument with anyone who would converse with him, his aim being not to alter his opinion but to get at the truth. 

They relate that Euripides gave him the treatise of Heraclitus and asked his opinion upon it, and that his reply was, "The part I understand is excellent, and so too is, I dare say, the part I do not understand; but it needs a Delian diver to get to the bottom of it."

—Diogenes Laërtius, Lives of the Eminent Philosophers 2.22