Damasio takes himself to be criticizing Descartes, because of course, the book is called Descartes' Error. What is the essence of Damasio's criticism of Descartes? Well, it takes two different forms. In one of which Damasio wants to suggest is what he calls the �abyssal separation of mind and body� that we get with Descartes' dualism. That I would suggest is nothing new in the sense that we have already seen, and even Descartes' contemporaries were puzzled by a dualistic picture according to which it seems very puzzling how something purely non-physical like a Cartesian mind could have any causal interaction with something physical like a human body. Even though it seems that interaction happens all the time, when I do something so simple as to make a decision to lift up my hand. And likewise, knowledge of other minds is a problem that we've already discussed in the context of Cartesian dualism. So what Damasio refers to as the abyssal separation of mind and body, it's a genuine criticism, but it's not an original criticism. It's something that we had known about for centuries. But Damasio also has a criticism of Descartes in so far as he takes Descartes to be a sort of arch rationalist, and by virtue of being a rationalist, being committed to the idea that what he calls pure reason is going to be sufficient to help us make the best decisions that we can. I want to suggest that that's a, criticism that doesn't quite hit its mark for the following reason. Descartes, at least in the discussions that Damasio points towards, for example, meditations, discourse on method, etc. Those Cartesian discussions are not particularly concerned with practical rationality. They're much more focused on theoretical rationality. The use of clear and distinct perception to find out about the world. That's not a practical question, that's a question about how things are. And so the fact that we might or might not use our emotions in the form of somatic markers is going to be irrelevant to the question, how we do those things, firstly. And secondly, Descartes as a rationalist might be read as holding that we should keep our emotions in check even when deciding what to do. And in the practical realm that we should keep our emotions out of it, we should not make any appeal to our emotions when deciding what to do. But it seems to me that Descartes would actually, when he talks about things like what nature teaches me in various parts of the Meditations and elsewhere. Sometimes what Descartes refers to as, �what nature teaches me� precisely is reference to an emotional response to a situation. So I want to suggest that for Descartes, emotions are not inherently opposed to reason. So that while it's probably true that reason as, if we put it on a pedestal, it's not something that has any obvious room for the use of emotions in decision making. If we separate reason into two different types, practical and theoretical rationality, we can see that for theoretical rationality, emotions are just not generally speaking an issue, because with theoretical we're trying to figure out what is the case, not what to do. For practical rationality, emotions are allowed to count, they should count in many cases. And there's nothing in Descartes that would rule them out as being able to play a role in decision making in that practical rationality sense. So that while overall Damasio's criticism of Descartes and the Cartesian tradition is not something that is either terribly original or terribly accurate as an account of something that the Descartes can be criticized for. Nevertheless, I'm going to suggest that the hypothesis concerning somatic markers is a powerful, original one for our purposes. And it is especially important for understanding the nature of self-knowledge for precisely the reason that, even though you might have been affected by somatic markers all your life thus far, you might not have noticed that you were doing so. By bringing the conscious awareness, the existence of and the importance of somatically marked experience, we can see how things that were part of experience all our lives thus far have been affecting us are ones that we can now begin to pay attention to, and thereby learn something about ourselves. I hadn�t noticed it, but I cringe when I get that particular email from that particular party. Or I hadn�t noticed it, but I look upon that prospect with a certain amount of relish, excitement, enthusiasm. I was doing so but had not noticed I was doing so. And that could teach me something about my own feelings and thereby be a route to understanding myself. As a result it seems to me introspection and Socratic dialogue being two interesting and important aspects of self-knowledge; But a third that I want to put on the table for you now is learning about yourself by paying attention to your experiential, and thereby bodily reactions to things around you both in your current experience, past and future, thereby developing a more nuanced picture of what understanding ourselves comes to.