Thoughts about the cogito.

In his Meditations on First Philosophy, Descartes coined his most famous phrase

Cogito, ergo sum.

(or 'I think therefore I am'). I was wandering through a bookshop the other day and noticed a book called The Last Word by Thomas Nagel, an American philosopher based at NYU.

It seems (from the introduction - I'm not so good at the ol' reading lark yet...) that the idea of this book is essentially an apology for rationalism, the belief that human knowledge can be derived by careful consideration from an armchair. I could well be misinterpreting this, but as far as I can tell, Nagel thinks that subjectivism (that truth and knowledge are subjective notions which may vary from person to person) is a very pernicious influence in society.

The implications are widespread. Take for example issues presented by cosmopolitanism of modern societies. Cultures vary from country to country and although it can be said that many moral issues are agreed upon universally, there are clearly some divergences. In a democratic multicultural society with disparate moral codes, how should one resolve disputes? My own position is one of bewilderment. It seems that taking the subjectivist view and saying, 'Well, what is morally right for one side may not be the same as what is morally right for the other...', leads only to shoulder shrugging and a lack of resolution. In my mind therefore that although subjectivism is a convenient position to take logically, it is more than toothless when applied to real life. On the other hand, taking a more authoritarian and moral absolutist view is not satisfactory either - presenting people with moral rules - 'Drinking soda is wrong!' - which are to be agreed on universally is impractical.

Nagel's book then claims to have some ideas about how to justify rationalism and therefore be able to conjure absolute certainty, indubitable truth, from thin air (or at least our minds). So far, he has talked about Descartes cogito with much affection. The cogito is supposed to be a demonstration of our existence. As soon as one tries to doubt one's existence, one affirms it by thinking. Indeed, Descartes asks proposes 'So who am I? A thinking thing.' There are various objections to this, indeed some say that Descartes has rather a circular argument, presupposing the existence of this 'I' and endowing it with personal attributes which cannot be justified on purely logical grounds. Nagel's view is that there is some worth to the cogito, and I agree. Nagel gives this nice example:

After all, if someone responded to every challenge to tea-leaf reading as a method of deciding factual or practical questions by appealing to further consultation of the tea leaves, it would be thought absurd. Why is reasoning about challenges to reason different? The answer is that the appeal to reason is implicitly authorized by the challenge itself, so this is really a way of showing that the challenge is unintelligible. The charge of begging the question imples that there is an alternative - namely, to examine the reasons for and against the claim being challenged while suspending judgement about it. For the case of reasoning itself, however, no such alternative is available, since any considerations agains the objective validity of a type of reasoning are inevitably attempts to offer reasons against it, and these must be rationally asessed. ... In contrast, a challenge to the authority of tea leaves does not itself lead us back to the tea leaves.

This argument makes a lot of sense. It somehow tells us that we cannot doubt our own reasoning since this would involve something self-referential. Nagel goes on to say that reason is something which we just have to take on trust as being sound. That is not to say that one may not make mistakes reasoning, simply that these could be pointed out and corrected. I think he plans to argue from a sort of foundationalist standpoint having established the indubitability of reasoning.

There is some part of me that feels slightly uneasy about this though. It seems that the 'reason' Nagel is talking about is the 'synthetic analytic' that Kant proposed in the Critique of Pure Reason. Reason, in my view, is part of the apparatus of perception. Thinking long and hard may lead to greater understanding of the apparatus itself, but there is still a fundamental disconnect between what we can derive from sheer brute force logical computation in our heads and the real world outside. Nagel refers to this and claims that his reason is something quite different, but I'm not so sure.

Check out the Google books preview of The Last Word (and tell me what it's all about). Please also feel free to rant in the comments about how badly I've interpreted all of this.