I’ve recently written an essay, I love writing essays, ever since being at Cambridge when one wrote one’s essay to one’s supervisor. I’ve gone on writing essays and have just written one which is not yet published actually on Sherlock Holmes whom I like very much, really suggesting that the brain is Sherlock Holmes, that the brain is the super-detective. The analogy works like this, that when you’re looking at something and you’re seeing an object, let’s say a person or a pillar-box or anything, that object is not directly represented in the brain. There’s no direct representation, there’s a pattern in the retina on the eye, like a photograph, but the perception of the object is not given all in one go of the whole object at once. It is at the brain accepts bits of movement, bits of colour, bits of shape, puts all these things together and then creates the object in your mind from brain activity which is spread around in all sorts of different parts of the brain. So it’s quite different actually from a photograph or put it another way, when you look at a photograph and you see an object, your brain is doing an amazing amount of work, as it were, creating what the object probably is from that photograph and you see it as a person or, again, a pillar box because you know about people, you know about pillar boxes, you recognise this bit of shape as an eyebrow, that bit of shape is the bit where you put the letter in and so on, and then you construct the object actively in the brain. That is what perception does. Now, I think that’s exactly, in a way, what was going on with Sherlock Holmes. He had these clues, you know, he’d see the thing, it might be a horseshoe in the mud, in the shape of it, sees a little curved bit and he realises, oh, that must be Silver Blaze’s hoof marks, sort of thing, from a little twiddle in the mud, sort of thing, so I think this use of clues, actively creating the hypothesis that it’s the villain, let’s say, or that it’s a horse that was stolen, is exactly what’s happening in perception. I see the brain as the great detective, using clues, developing hypothesis and sometimes there’s not enough information either available to the eye or from one’s background knowledge, you need both, to create the hypothesis and then you either can’t see, you’re blind, or you see the wrong thing, your hypothesis is not appropriate or correct. And I think it’s exactly the same with Sherlock Holmes and how we see the world.