Of course, there are many right answers to this question. But was a man who was mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, theory of sets, linguistics, artificial intelligence, cognitive science, computer science and various areas of analytic philosophy, especially philosophy of mathematics, philosophy of language, epistemology, and metaphysics.
During his lifetime he declared himself to be a liberal, a socialist and a pacifist, but at the same time he admitted that he was really none of these things. He was friend and enemy of paradox, he is the one who annoyed the most people, from Socrates onwards.
It is to him that I thought for this hanjie.