I’d quite like to, you know, think a bit about, talk a bit about science itself and how science is related to perception and how we make decisions in science for our lives and how the brain makes decision which are sort of pre scientific. I mean the brain comes up with its own decisions and then it gets into science to be analysed, made explicit and then scientific method applied. All this, I think, is a hugely important issue; indeed, our survival might actually depend on doing it properly. It always has done, since primitive man, with agriculture. How do I plant this field so I’m likely to have grub next year, you know? It’s always been a probability issue. Now, I think an important character here is Ockham, William Ockham, who round about the 11th century, I can’t remember his exact date, approximately 11th century, who was a philosopher. I think he lived in Bath, actually, and he simply made the statement that you have a load of hypothesis and what you should not do is to have more assumptions for testing each hypothesis than are absolutely needed. You need the simplest possible account. You can always multiply excuses, if you like, or possible bits of new evidence or something which may be imaginary to support the hypothesis but he said, no, you should make it minimal, minimum number of hypothesis, minimum number of assumptions and then you’ve got the most powerful hypothesis. And I think he really had the idea that probabilities were involved here that the hypothesis is supported by the evidence or it can be thrown away but the thing is, it’s not black and white. You can very seldom be certain that a hypothesis is wrong or certain that it’s right. We’re pretty certain that the moon is not made of green cheese. In other words, that would be a waste of time even considering that as a scientific project, to see whether it’s made of green cheese. But where does this stop? If you want to ask is it possible to make a bomb out of uranium, 100 years ago this would have been like green cheese moon. It would have been regarded as ridiculous. Then it creeps up on you and, by golly, it isn’t only a possibility, it happens, and then you’ve got the thing, how to deal with it when you’ve got it and the probabilities keep changing. So I think that science and also the perceptual brain is always playing with probabilities and the trick is to minimise and simplify each hypothesis so that you can really say, well, this is probably right or it’s probably wrong and apply the evidence effectively, and you can only do that when it’s simple, when it’s defined. This is really from Ockham.