§ 4. THE SOPHISTS.

12. Protagoras and Gorgias. -- The nature-philosophers had fixed their attention on the external world exclusively, paying no heed to the knowing subject, -- to the nature and working of his cognoscitive faculties. A group of controversially minded thinkers seized on this popular physical philosophy for the purpose of proving that it really led to the destruction of all knowledge: they got the name of Sophists. Their scepticism has in it no independent or absolute value, for it is inspired by the philosophies of Heraclitus and Parmenides. Rather it prepares the way for a fuller and richer dogmatism by convincing Socrates of the need to compare and complete cosmological researches by psychology.

The leading sophists are PROTAGORAS (born at Abdera, about 480) and GORGIAS (about 480-375). Heraclitus had declared that all is change. Protagoras now added: this change itself depends on our subjective state. The external world is a creation of the mind: and since two men may construct their world in contradictory ways, it follows that truth is relative and science impossible.

Gorgias, a contemporary of Protagoras, followed the latter to Athens, where his oratorical gifts won him much celebrity. Starting from the Eleatic doctrines, he ended by asserting the utter bankruptcy of science. The negation of absolute truth as a fixed standard for all should naturally lead to the denial of a uniform moral code. And Protagoras and Gorgias were only logical when they taught that right and wrong depend on each man's own sweet will.

The sophists exposed the weaknesses of the philosophy of their day, but they made no attempt to remedy them. It remained for Socrates to rebuild the tottering fabric of science on safer foundations; his teaching both completes the work of the nature-philosophers and refutes the theories of the sophists.