This paper evaluates Peter Klein’s objection to foundationalism. According to Klein, foundationalism fails because it allows arbitrariness “at the base.” I first explain that this objection can be interpreted in two ways: either as targeting dialectical foundationalism or as targeting epistemic foundationalism. I then clarify Klein’s concept of arbitrariness. An assertion or belief is assumed to be arbitrary if and only if it lacks a reason that is “objectively and subjectively available.” Drawing on this notion, I evaluate Klein’s objection. I (...) first argue that his objection construed as targeting dialectical foundationalism fails, since nothing prevents dialectical foundationalism from ruling out arbitrary assertions. I then argue that the objection seen as targeting epistemic foundationalism cannot be disqualified in the way some foundationalists believe. However, I show that also the objection so construed does not succeed, since epistemic foundationalism need not countenance arbitrary beliefs. (shrink)