Self-Knowledge

Descartes: The Classic Conception

Modern philosophy began with René Descartes (1596–1650), especially his epistemological and metaphysical writings. Discourse on the Method and Meditations on First Philosophy exemplify autobiographical and introspective philosophy: Descartes tried to ascertain for himself what he knows, first questioning whether he knows anything at all. In “Meditation I,” he wondered whether his beliefs ostensibly resulting from observing the physical world might be mistaken by being present within a dreaming experience. He then postulated as possible an evil demon deceiving him in all his beliefs, even those apparently due to reason.

This is where a concept of self-knowledge entered the story. In “Meditation II,” Descartes reflected that with some of his beliefs it was impossible to be deceived. Being deceived involves thinking. So even when whatever one is thinking is the result of being deceived, one cannot be mistaken in thinking that one is thinking; and thinking includes existing. That was Descartes's cogito. Its most celebrated version is cogito ergo sum—”I think, therefore I am”—from the Discourse. Descartes claimed similarly invulnerable knowledge of his particular acts of thought—doubting, imagining, willing, and so forth. Thus, a self was described—known by that same self, immune from skeptical doubt. This is philosophy's locus classicus of putative self-knowledge.

Hume: The Self as Bundle

For Descartes, the known self was a mentally active substance. David Hume (1711–1776), in A Treatise of Human Nature, advocated a contrary picture, reflecting on how a self would be known. Hume allowed that there is mental activity with mental content. However (he concluded), no inner substance is knowable as the agent of that activity. We would know such a substance by introspectively discovering its accompanying the mental contents. Yet whenever we introspect to effect that discovery, we find only more mental contents. We do not discover also an inner substantial self. Hume did infer, nonetheless, that selves exist. But his was a distinct [Page 857]conception: The self is a mere bundle or collection of those mental contents—not an entity, or substance, over and above those.

Kant: Two Selves

Immanuel Kant (1724–1804), in the Critique of Pure Reason, distinguished between the self as experienced (the phenomenal self) and the real self (the noumenal self). We can know only the former—one's self as involved in having experiences. There is no such experience—hence no knowledge—of a real self characterizable apart from one's having the experiences. Inevitably, though, we continue believing that such a self exists; we organize our thoughts as if it does. That is part of how we conceive even of experiencing a world beyond ourselves. You do not know your self as an object; you think of it as a subject.

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