 A central problem in epistemology is to explain when we are justified in holding a proposition to be true. It is not at all evident what epistemic justification is, and classical accounts of that notion have turned out to be severely problematic. A tradition inspired by Descartes holds that justified beliefs are those that are either self-evidently true or deduced from self-evident truths.  But, as is often argued, little of what we take ourselves to justifiably believe satisfies these austere conditions: many of our apparently justified beliefs, it is commonly thought, are neither based on self-evident truths nor derivable in a strict logical sense from other things we believe in. Thus, the Cartesian rationalist picture of justification seems far too restrictive. Similar problems hound empiricist attempts to ground all our knowledge in the allegedly indubitable data of the senses. Depending on how they are understood, sense data are either not indubitable or else not informative enough to justify a sufficient portion of our purported knowledge. The exact characterization of foundationalism is a somewhat contentious issue. There is another form of foundationalism according to which some beliefs have some non-doxastic source of epistemic support that requires no support of its own. This support can be defeasible and it can require supplementation to be strong enough for knowledge. This sort of non-doxastic support would terminate the regress of justification. To do so it may not have to appeal to self-evidence, indubitability or certainty. Such foundationalist views vary on the source of the non-doxastic support, how strong the support is on its own, and what role in justification coherence plays, if any. Some critics of this position have questioned the intelligibility of the non-doxastic support relation. Thus, Davidson (1986) complains that advocates have been unable to explain the relation between experience and belief that allows the first to justify the second.