In epistemology, the regress argument is the argument that any proposition requires a justification. However, any justification itself requires support. This means that any proposition whatsoever can be endlessly (infinitely) questioned, resulting in infinite regress. It is a problem in epistemology and in any general situation where a statement has to be justified. The argument is also known as diallelus (Latin) or diallelon, from Greek di' allelon "through or by means of one another" and as the epistemic regress problem. It is an element of the Münchhausen trilemma. Structure Assuming that knowledge is justified true belief, then: Suppose that P is some piece of knowledge. Then P is a justified true belief. The only thing that can justify P is another statement – let's call it P1; so P1 justifies P. But if P1 is to be a satisfactory justification for P, then we must know that P1 is true. But for P1 to be known, it must also be a justified true belief. That justification will be another statement - let's call it P2; so P2 justifies P1. But if P2 is to be a satisfactory justification for P1, then we must know that P2 is true But for P2 to count as knowledge, it must itself be a justified true belief. That justification will in turn be another statement - let's call it P3; so P3 justifies P2. and so on, ad infinitum. Responses Throughout history many responses to this problem have been generated. The major counter-arguments are some statements do not need justification, the chain of reasoning loops back on itself, the sequence never finishes, belief cannot be justified as beyond doubt. Foundationalism Perhaps the chain begins with a belief that is justified, but which is not justified by another belief. Such beliefs are called basic beliefs. In this solution, which is called foundationalism, all beliefs are justified by basic beliefs. Foundationalism seeks to escape the regress argument by claiming that there are some beliefs for which it is improper to ask for a justification. (See also a priori.) This would be a claim that some things (basic beliefs) are true in and of themselves. Foundationalism is the belief that a chain of justification begins with a belief that is justified, but which is not justified by another belief. Thus, a belief is justified if and only if: it is a basic/foundational belief, or it is justified