25 April

Dementia shows that memory is an entirely practical faculty. We need to remember to be able to do things. Memory is what makes us think that time passes, that we are mortal, because it makes our lives seem to have a sequence of before, now, and after. But actually its real function is just to let us do things. Look at this dementia home, designed to prompt memories to help dementia patients function. Dementia patients seem sick to us, but actually they're living a bit of time in its pure state - eternity. A dream, literally, dreams are where all of us visit eternity every day. They have hallucinations and delusions, but that's their lives decoupled from practical activity, which plunges them into a world where things don't follow neat cause and effect, where things don't pass, there's no sense of a 'flow' of time. That flow is an illusion created by our need to act in the world, you can't act without a logical sense of before and after.