What to put on a T-shirt?

We’re thinking of making some “Philosophy” t-shirts, available in the fall. I’ve suggested they could be black, with a philosophy symbol on the front (like a Greek letter phi) and some snappy, funny, or edgy saying on the back. Any suggestions? Here are some contenders: “It’s the mind that matters”, “The unexamined life sucks”, “Wherever you go, there you are”, “We can only say of what is, that it is”, and my own personal favorite: “What are you afraid of?”