So welcome to this course on Visual Perception and the Brain. I hope you'll enjoy it. It's been fun for me. And I'll try to go along at a speed I think that doesn't lose you, even though we're talking about some pretty complicated things. So let me begin by telling you a little bit about the course. Incidentally, I mean you can find all the details about the course by looking on the Coursera site. And you can also find out about me, as the instructor, on the Coursera site or by going to my website, purves.net, and look at my CV and find out all the things that I've been interested in over the years. The course is not the usual approach to vision and I think I don't take kind of a standard approach to it in my own thinking about it. Our focus in this course on perception as a guide to the strategy and mechanisms of vision. And that's really turning things on their head in the sense that most courses on vision would focus on strategy and mechanisms by telling you a lot about the anatomy and physiology of the visual system. And come to the end, to talk about perception as kind of an add-on. Well it's obviously the end result of visual processing, but perception has always been kind of apart from anatomy and physiology as something that psychologists deal with. I'm going to turn things around and talk mainly about perception. And what perception tells us about the way in which vision works. And the reason for doing that is that the standard anatomical and physiological ways in which people talk about vision. And they talk about them very well, and I should emphasize that there's an enormous wealth of information about the visual system and how it works that's accumulated mainly over the past 50 years but really over the last century or so. But I think every vision scientist, and certainly I would put myself in this category, would admit that these approaches, physiology, anatomy, that all of that information that have been so painstakingly gained by beautiful experiments over more than a century now, can't really explain or haven't been able to explain perception. Well perception's what we end up seeing, as I said, that's what leads us to be able to behave in the world correctly, presumably. We perceive things and we act accordingly, we behave and we succeed in that behavior. But no one today can tell you that they can explain how it is that anatomy and physiology really lead to the perceptions that we have. And I'm going to go through in this first module and tell you quite a bit about what the problem is. So that's a real problem, if you can't explain perception and perception is really the end product of vision, what it's all about, what leads us to correct behavior. No vision scientist can be satisfied without being able to explain it, and no one can. And this is really equivalent because one knows so much about vision, it's far and away the part of the brain about which most is known. Saying that we can't explain perception and vision is kind of tantamount to saying, we don't really understand the brain works. And I think any neuroscientist would again admit, certainly I would, that we don't really understand how the brain works. So the goal of understanding how the brain works is very much going to be informed by how vision works, understanding how vision works. It's likely to be the place where the principles of brain operation are going to be revealed if again, we're able to reveal those principles. And as a scientist, I have every confidence that sooner or later we will indeed have a much better understanding of the brain than we have right now. So the basis of the course, is really to take the phenomenology of perception and use that to explain how it is. Or to try and explain how it is, or at least to get some clues that might explain how it is that vision really works. Phenomenology is a $10 word but basically, it's just referring to what we see. What we perceive and how that's related to the physical reality that well, maybe there are some strange philosophers out there who question physical reality, but for the rest of us we certainly assume that it's out there. And we behave in that world and yet we don't see it, as we'll go on to talk about in the first of the five modules.
