  The NRB view instead argues that universal suspension isn’t opposed to beliefs per se, but only to beliefs justified through philosophical theory or reasons generally. The Stoics maintain that the mind is essentially rational, so that its assent is necessarily reason-responsive (see Coope 2016). Arcesilaus’ skepticism, on this view, challenges the rationalist presupposition that belief is necessarily and explicitly grounded in reason. This doesn’t preclude that Arcesilaus found himself—as a result of the inadequacy of the arguments for any position, and of the equally convincing arguments against it—with the belief that nothing can be known. Thus, inapprehensibility is neither the conclusion of a deductive argument relying on a theory of knowledge or of our cognitive faculties, nor an inductive inference from prior investigations; it is not a theoretical or even rationally warranted belief, but just the way things strike him (see Cooper 2004 and Thorsrud 2009).