the idea of a difference between matter and spirit. this idea doesn’t work anymore. long, long ago, physicists stopped asking the question ‘what is matter?’ they began that way. they wanted to know, what is the fundamental substance of the world? and the more they asked that question, the more they realized the couldn’t answer it, because if you’re going to say what matter is, you’ve got to describe it in terms of behaviour, that is to say in terms of form, in terms of pattern. you tell what it does, you describe the smallest shapes of it which you can see. do you see what happens? you look, say, at a piece of stone, and you want to say, ‘well, what is this piece of stone made of?’ you take your microscope and you look at it, and instead of just this block of stuff, you see ever so many tinier shapes. little crystals. so you say, ‘fine, so far so good. now what are these crystals made of?’ and you take a more powerful instrument, and you find that they’re made of molocules, and then you take a still more powerful instrument to find out what the molocules are made of, and you begin to describe atoms, electrons, protons, mesons, all sorts of sub-nuclear particles. but you never, never arrive at the basic stuff. because there isn’t any.