 This argument suffers from various weaknesses. First, we may wonder whether the alternatives to foundationalism are really unacceptable. In the recent literature on this subject, we actually find an elaborate defense of the position that infinitism is the correct solution to the regress  problem.[50]  Nor should circularity be dismissed too quickly. The issue is not whether a simple argument of the form p therefore p can justify the belief that p. Of course it cannot. Rather, the issue is ultimately whether, in the attempt to show that trust in our faculties is reasonable, we may make use of the input our faculties deliver. Whether such circularity is as unacceptable as a p-therefore-p inference is an open question. Moreover, the avoidance of circularity does not come cheap. Experiential foundationalists claim that perception is a source of justification. Hence they need to answer the J-question: Why is perception a source of justification? As we saw above, if we wish to answer this question without committing ourselves to the kind of circularity dependence coherentism involves, we must choose between externalism and an appeal to brute necessity.