I think because we have this storytelling function, we end up telling stories about the world, and so I think that the idea of cause and effect is actually not something that's really in the world. It's just a story we tell about the world. So if we take something in physics, like F=ma, we tend to think of a force as causing acceleration, but that equation can be rearranged. You could think of acceleration as causing mass, or mass as causing force. Mathematically, it's all the same. We think of it that way because we can create forces by pushing on something. And we can't create masses by willing something, so we tend to think of the force as the cause. So it's really just kind of a storytelling convention. So I believe actually all the stories we tell about the cause and effect of things are either false, if they are about real things in the physical world, or they're constructed if they're in things we engineer. So for instance on a computer, we deliberately construct electronic circuits that have... implement cause and effect. The input can affect the output, but the output really can't affect the input. And so we create something that is our fantasy of cause and effect, as in a logic gate. And then we connect all those together and we build these fantastic chains of causes and effect in computer programs and things like that. And so those things really do have cause and effect, because they were built to. It may be that evolution builds things with causes and effects for similar reasons, but I think mostly in physical systems, causes and effects are just something that we make up about a system in order to explain it. And in fact, probably complicated systems like economies or ecologies or maybe even brains aren't really explainable in those terms. And so it may be that trying to understand those things in the same sense that we understand a computer circuit may just be impossible.