Internalism and Externalism in Early Modern Epistemology

Do Descartes, Locke, and Hume have an internalist or externalist view of epistemic justification? Internalism is, roughly, the view that a belief that p is justified by a mental state, such as the awareness of evidence. By contrast, externalism is, roughly, the view that a belief that p is justified by facts about the belief-forming process, such as the reliability of the belief-forming process. I argue that they all think that the awareness of evidence is required for justification, but none of them think that the awareness of evidence alone is sufficient for justification. Similarly, I argue that they all think that reliability of the belief-forming process is required for justification, but none of them think reliability alone is sufficient for justification. So, neither a fully internalist position nor a fully externalist position adequately captures their views of justification; rather, both the supporting evidence and the reliability of the belief-forming process explain why we should hold those beliefs, and hence explain why those beliefs are justified. Thus, they each have a partly internalist, partly externalist view of justification.