THESE THINGS I HOLD to be self-evident: that pictures have frames: that art has a history more than one in fact; that you can paint from a model; that things sometimes look alike; that I shall be talking about a painter named René Magritte. My theme (his theme) will be the doubts that hover in the atmosphere like old smells around any piece of self-evidence. René Magritte, the artist in dark overcoat and derby, presents credentials as a wallpaper painter, speculative semanticist, and frame-up operator. Here’s what he does. He takes the entire Western tradition of optical likeness, perfected