As you'll learn throughout the course of these classes in the Know Thyself course, whenever I discuss a theorist who often will criticize somebody else, I'll often try to put some pressure on that by criticizing them too, and I want to spend a little bit of time talking about potential challenges to Ryle after we've seen him challenge Descartes. Once such challenge is the following, we said that for Ryle, mindedness is a matter of being disposed to behave in intelligent ways, but you might ask about potential challenges to that. So, for example, there's the case of what's known as locked-in syndrome, in which a person is paralyzed. In some cases, the paralysis includes everything except for a person's eyelids, and they might able to blink their eyelids, and because of that, can painstakingly communicate with others if they can develop a code system correlating numbers of blinks of eyelids with letters of the alphabet. Imagine how difficult that would be, but at least, it would be a chance to communicate with the outside world if you have locked-in syndrome. In other more extreme cases, as I understand it, advanced cases of Lou Gehrig's disease will bring this about, not just locked-in syndrome but also cases which you can't even blink your eyelids, so he can't move any muscles at all, at least those that are under voluntary control. Now, in that kind of case, you might say, It still seems like a person like that could think. Imagine being wholly and completely paralyzed, it still seems like at least for a while you'd be able to imagine what you did yesterday, you didn't try to figure out what happened to you, because you just woke up in the hospital and find that you can't move any part of your body, or think back on events from your childhood, or perhaps you'll form an image of what you wish you were doing right now, or imagine a triangle or a golden mountain. Those all seem to be things you can do and more precisely, their mental phenomena, but you might ask, Well, in what sense are they behavior? Aren't these cases of thinking that don't involve any kind of behavior? I think Ryle, I'm not sure exactly what Ryle would say about this because he tended to be a bit dismissive about cases from the sciences as potentially important for understanding the mind. As we saw, he holds that we know everything we need to know about the mind just by virtue of the fact that we've got access to common sense, but a contemporary defender of Ryle who's reasonably well up-to-date with neuroscience and experimental psychology might say, "Behaviour is not identical with bodily motions. Bodily movements that are intentional under our control are going to be one kind of behavior, but they're not the only kind." So, as long as we described before behavior as something that is effortful, requires an amount of effort, and it's something that which we do have control. But notice that, and that characterization of behaviour, even someone who's suffering from locked-in syndrome can still behave. Imagine that she attempts to, for example, count backwards from 100 by three. She will have to engage in and exert some effort to do so. The course of that, for example, she might get stuck at a certain point, she might get distracted, she might decide to stop. So, that activity on her part of counting backwards from 100 by threes is going to be something that meets our criteria for behavior. It's effortful and something that's under her control. If that's right, then even somebody who can't move a single muscle can still behave. It might be that nowadays we might detect some of that behavior by virtue of an MRI machine or fMRI type of device, but that doesn't prevent it from being an application of mind and as well as an application of behavior at the same time. So, I would suggest that a contemporary Rylian doesn't have to completely give up her view in light of examples like locked-in syndrome. I'll come back in a moment to other questions that we might raise about Ryle's view.