The techniques in terms of molecular biology are really rather backward and rather slow but that’s because the system’s very difficult, and molecular biologists happen to be very good at developing these techniques so that… so that they… they work on a much faster time scale in… in molecular biology than they do in the so-called neurosciences, that’s… that’s the one thing. The other thing is we don’t have a… we can’t answer… we don’t have a good set of general principles. We know certain things about the way neurons send out signals, we know… and roughly the type of signals they are but we’re very unclear what… how the… how an individual neuron actually collects the signals, decides whether to send out its spike or not, for example. And… when you come to the action of very many neurons together, very many nerve cells, then we don’t understand that at all really. We’re just groping with explanations and feeling our way. We don’t have what you might call the overall… or we don’t know the overall organisation of the brain. We know there’s a bit here and a bit there and a bit there and that they’re connected but we don’t… they’re not very clear exactly what this job does. Now, when you come to different parts of the body that’s not true. We know roughly what the liver does; the liver is the organ of the blood, is the classic way of saying it, we know that, we know many of the operations that go into it. It isn’t the only thing concerned with the blood because the heart pumps the blood, for example. We know all those for the major organs of the… of the body, but when you look at the subdivisions of the brain we really don’t know the answers. We have… we have provisional guesses and probably some of those will be on the right lines, but we don’t have good crisp answers which you think are likely to be fairly stable for some time. And that’s why it’s going to take much longer.