If we are to believe his student Plato, Socrates was always asking people about what they knew, and invariably they had to admit that they did not really understand what was meant by words like courage, friendship, love etc.
Socrates was never without critics. The comic poet Aristophanes ridiculed him in The clouds, and when his pupil Alcibiades had committed high treason, Socrates' position became very difficult. He was forced to drink hemlock after a charge that he had corrupted the youth.
Socrates left no writings. His ideas must be reconstructed from the publications of his students, which include the philosophers Antisthenes and Plato and the historian Xenophon.