Epistemologists have always recognized the importance of causal processes in accounting for our knowledge of things. In discussions of perception, memory and reasoning, for example, it is commonly assumed that these ways of coming to know are fundamentally causal. We perceive things and thus come to have knowledge about them via complex causal processes; memory is, at least in part, the retention of previously gained knowledge through some sort of causal process; and reasoning is a causal process that takes beliefs as inputs and generates beliefs as outputs.
A causal theory of knowledge is a form of externalism and is based on the fundamental idea that a person knows some proposition, p, only if there is an appropriate causal connection between the state of affairs that makes p true and the person’s belief in p. Although this kind of theory has roots that extend to ancient times, contemporary versions attempt to make more precise the nature of the causal connections required for knowledge. The causal theory is closely related to other forms of externalist theories, such as the conclusive reasons theory, information-theoretic views and the various forms of reliabilism.
The causal theory of knowledge revisited: An interventionist approach