When you see a red apple and I see a red apple, we agree on the word. But is the inner experience — the actual felt quality of redness as it appears to your consciousness — the same as mine? Philosophers have generated enormous literature on this problem. Wittgenstein looked at it and said: wait. Before we try to answer the question, let us ask whether we have properly understood what we are asking.

Ludwig Wittgenstein is probably the most influential philosopher of the twentieth century. He also, unusually, produced two major works that contradict each other in important ways — and repudiated the first while writing the second. In this episode, Shawn and Claire cover both.

The early Wittgenstein — the Tractatus Logico-Philosophicus — argued that language pictures the facts of the world, that meaningful propositions correspon ...