  So, according to the Lange-Vaihinger view, the objects of our experience are the joint product of affection by things in themselves and the operations of our physiological organization. This is supposed to have the conclusion that things in themselves are entirely unknowable, a fortiori not knowable through the methods of the empirical sciences. The problem becomes clear, then, when we ask what sort of thing ‘physiological organization’ is supposed to signify. If it refers to a thing in itself (the cognitive apparatus in itself), then the empirical sciences could establish nothing about it. In this case, the Langean argument is entirely impotent. If it refers to an appearance, then there is evidently a circle in the argument: the existence of appearances is supposed to be explained by the causal collaboration of things in themselves and the perceptual apparatus, but the perceptual apparatus is itself an appearance. Finally, if the physiological organization is both an appearance and a thing in itself, then the empirical sciences can in fact yield knowledge of at least some things in themselves. This, of course, is precisely what the argument is meant to forestall.