Now, so much for consciousness, now there’s another problem that I see as almost the same that concerns a lot of modern philosophers. And that is... they have a special word called qualia. And they use this wonderful word, qualia, to refer to the character of sensations. So for example, we can say an object is red or another object is green. Now, about 10% of people don’t make that distinction very well because – particularly men – because red green color blindness is rather more common that most people who don’t have it realize. But…. but so… that’s an example of something. But what many believe or like to think is that there’s something very simple, clear, and absolute about the qualia of a sensation. Like something hurts or something is red or something is hard or soft. Well that’s… not a bad example. And so, they say, well how do you explain the existence of characteristics like certain colors and certain sensations and…? How do you explain the difference between pain and pleasure and…? Why… what are these qualities that seem so simple, absolute, and clear that you can’t explain them? And the answer is, you can’t explain them because you’re too lazy. There aren’t any such things. The process by which the nervous system discovers or identifies something as red is extremely complicated.

For example, if you have a visual system where there’s one color here and another color here, then it can be very difficult – if there’s nothing else in the scene – to identify those colors because all you can see is the difference. And in fact, Edwin Land discovered that in many cases you can’t identify... you don’t have the sensation of a definite color unless there are three regions that are optically… that have optically different colors coming together. If there are just two regions, then your sense of what color the two regions are can keep changing or can be different from what it would be if… if you put it on a table with a third color. So, it turns out that these qualia are not absolute. As far as I can see, they depend on all sorts of complicated processes running in between. So, the sense that you say something is pink or something is orange seems very immediate, but that’s because... let’s take another example. How do you… why did you say the word orange? Everybody knows the words they just said because one of the 30 or 40 meanings of that word, consciousness, is remembering what you’ve recently done, but nobody knows how you… what process caused you to emit the word orange. Is there just a connection between the color receptor in the retina and a thing in your speech centre that produces the word orange? No, there’s no reason to think anything is that simple. There's probably 15 or 20 different layers of processes.