The Unknowable is a nominalistic heresy. The nominalists in giving their adherence to that doctrine which is really held by all philosophers of all stripes, namely, that experience is all we know, understand experience in their nominalistic sense as the mere first impressions of sense. These “first impressions of sense” are hypothetical creations of nominalistic metaphysics: I for one deny their existence. But anyway even if they exist, it is not in them that experience consists.