Doctrine that knowledge must have foundations; that is, if we are to know anything at all there must be some things that we can know incorrigibly, so that it is impossible – or perhaps does not even make sense – for us to be mistaken.
The usual candidates for such knowledge have been facts about the immediate data of the senses or of introspection, such as what colors, tastes, and so on, are currently present to us, or what state of feeling or state of mind we are in.
But probably the most famous foundationalist statement has been that of Rene Descartes (1596-1650): ‘Cogito ergo sum’ (‘I think therefore I am’). One objection to foundationalism is that it is hard to make knowledge incorrigible without constricting it so far that it ceases to be knowledge at all (one can misclassify even one’s own immediate experiences).
R Descartes, Meditations on the First Philosophy (1641), especially Meditations 1 and 2
Foundationalism concerns philosophical theories of knowledge resting upon justified belief, or some secure foundation of certainty such as a conclusion inferred from a basis of sound premises. The main rival of the foundationalist theory of justification is the coherence theory of justification, whereby a body of knowledge, not requiring a secure foundation, can be established by the interlocking strength of its components, like a puzzle solved without prior certainty that each small region was solved correctly.
Identifying the alternatives as either circular reasoning or infinite regress, and thus exhibiting the regress problem, Aristotle made foundationalism his own clear choice, positing basic beliefs underpinning others. Descartes, the most famed foundationalist, discovered a foundation in the fact of his own existence and in the “clear and distinct” ideas of reason, whereas Locke found a foundation in experience. Differing foundations may reflect differing epistemological emphases—empiricists emphasizing experience, rationalists emphasizing reason—but may blend both.
In the 1930s, debate over foundationalism revived. Whereas Moritz Schlick viewed scientific knowledge like a pyramid where a special class of statements does not require verification through other beliefs and serves as a foundation, Otto Neurath argued that scientific knowledge lacks an ultimate foundation and acts like a raft. In the 1950s, foundationalism fell into decline – largely due to the influence of Willard Van Orman Quine, whose ontological relativity found any belief networked to one’s beliefs on all of reality, while auxiliary beliefs somewhere in the vast network are readily modified to protect desired beliefs.
Classically, foundationalism had posited infallibility of basic beliefs and deductive reasoning between beliefs—a strong foundationalism. Around 1975, weak foundationalism emerged. Thus recent foundationalists have variously allowed fallible basic beliefs, and inductive reasoning between them, either by enumerative induction or by inference to the best explanation. And whereas internalists require cognitive access to justificatory means, externalists find justification without such access