May asked:

After reading the ‘Discourse on Method’ text, I had this one question in my head, Why did Descartes prefer self-observation or ‘learning by himself’, to studying/ travelling?

Answer by Geoffrey Klempner

We know that Descartes studied and travelled extensively. Why weren’t these enough? What did he hope to learn by self-observation?

This might seem a rather naive question, as we are so used to the idea of philosophers sitting alone in their studies (Descartes preferred the warm comfort of his bed) exploring the contents of their own minds, but Descartes wasn’t merely mulling over all the things he’d learned and experienced. By self-observation he hoped to discover new knowledge.

The idea of using the mind rather than the senses as a source of knowledge goes right back to the Ancient Greeks and the Presocratic philosopher Parmenides. The idea of examining ourselves and becoming self-aware was first given powerful expression by the Presocratic philosopher Heraclitus, who in a vision saw that the soul of a human being was one and the same as the principle that governs the universe, the fiery Logos. It was Heraclitus’ successor Socrates who proposed ‘Know thyself’ as the basis for all philosophical inquiry.

Descartes was fully aware of these precedents. Nor was he the first to write in the way he did. The confessional or self-observational style of thinking and philosophizing had been pioneered by Montaigne. Yet Descartes was also aware that he was doing something radically new. By looking inside his own mind and describing what he found there, he hoped to discover a new basis for metaphysics or ‘first philosophy’ (Aristotle’s term for the inquiry that subsequently came to be known as metaphysics).

Hence the title of Descartes’ major work: ‘Meditations on the First Philosophy in which the existence of God and the real distinction between the soul and the body of man are demonstrated.’

I happen to think that this was, possibly, the most important event in the history of philosophy.

I see the principle of egocentricity as central to metaphysical inquiry. This isn’t about Descartes’ claim, his theory of mind-body dualism and the notion of the mind as a ‘mental substance’, but rather the question that Descartes raised.

Of contemporary philosophers, Thomas Nagel comes closest to grappling with this in The View From Nowhere where he discusses the proposition ‘I am TN’.

My take would be this. What distinguishes metaphysics from science or empirical inquiry – or all the knowledge that you can get by studying or travelling or etc. – is that I am asking the question. Obviously, when I say ‘I’, I also mean you, or whoever happens to be reading this. You are the one asking the question. That is to say, You, your very existence, or the fact that you are asking a question is part of that question, not something that can be discounted or factored out in the way that we do with every other form of human knowledge.

To this day no philosopher has succeeded in completing the search that Descartes initiated. Sure, lots of ‘metaphysics’ has been done since the time of Descartes, but none of the theories put forward, and I include the great traditions of idealism and existentialism, has succeeded in capturing the evanescent intuition that I, my very existence – not just anyone or the ‘self’ in general – is an essential part of the puzzle of reality.