Introspection, epistemology of

If we wish to know what is going on in someone else’s mind, we must observe their behaviour; on the basis of what we observe, we may sometimes reasonably draw a conclusion about the person’s mental state. Thus, for example, on seeing someone smile, we infer that they are happy; on seeing someone scowl, we infer that they are upset. But this is not, at least typically, the way in which we come to know our own mental states. We do not need to examine our own behaviour in order to know how we feel, what we believe, what we want and so on. Our understanding of these things is more direct than our understanding of the mental states of others, it seems. The term used to describe this special mode of access which we seem to have to our own mental states is ‘introspection’.

A view which takes its inspiration from Descartes holds that introspection provides us with infallible and complete access to our states of mind. On this view, introspection provides us with a foundation for our knowledge of the physical world. On this view we come to know the physical world by first coming to recognize certain features of our mind, namely, the sensations which physical objects excite in us, and then drawing conclusions about the likely source of these mental states. Our knowledge of the physical world is thus indirect; it is grounded in the direct knowledge we have of our own minds. The view that introspection provides an infallible and complete picture of the mind, however, is no longer widely accepted.

Introspection has also been called upon to support various metaphysical conclusions. Descartes argued for dualism on the basis of introspective evidence, and certain contemporary philosophers have argued in much the same spirit. Hume noted that introspection does not reveal the presence of an enduring self, but only a series of fleeting perceptions; some have concluded, therefore, that there is no enduring self.

Philosophers concerned with self-improvement, whether epistemological or moral, have frequently called upon introspection. Introspection has been thought to aid in forming beliefs on the basis of adequate evidence, and it has been used as a tool of self-scrutiny by those concerned to understand and refine their motivations and characters.