Common Sense and A Priori Epistemology

Some philosophers have adopted both a commonsense approach to the theory of knowledge and held that some epistemic principles are knowable a priori. Roderick Chisholm is a prominent example of a philosopher who does both. In The Problem of the Criterion, Chisholm holds that in attempting to discover criteria of evidence we should begin with particular commonsense examples of knowledge, such as I know that I have two hands and I know that there are other people. According to Chisholm, our knowledge of these particular epistemic facts does not depend upon our knowing criteria of evidence or knowledge. Moreover, we may reject various criteria of evidence and knowledge because they do not fit with these particular epistemic facts. Thus, according to Chisholm, we may reject the empiricist criterion of knowledge held by Locke and Hume because it implies that we do not know things that we do in fact know, because it conflicts with our commonsense epistemic beliefs.