How can one learn the truth by thinking? As one learns to see a face better if one draws it. Ludwig Wittgenstein, Zettel §255 This remark, like many of Wittgenstein’s, seems to arise from self-examination. The answer he gives suggests that he is concerned with learning just by thinking, and indeed with the particular kind of learning just by thinking that happens in philosophy (as opposed to, say, mathematics). He seems to be asking how such learning is even possible. What are we to make of his answer? I remember being surprised when I was taught where to place the…