"How can anyone communicate the idea of color by means of words since the ear does not hear colors but only sounds?" This quote was used to show his theory that 'there is nothing', 'if there were anything no one would know it', 'and if anyone did know it, no one could communicate it'. This theory, thought of in the late 5th century BC, is still being contemplated by many philosophers throughout the world. This argument has led some to label Gorgias a nihilist (one who believes nothing exists, or that the world is incomprehensible, and that the concept of truth is fictitious).