course it cannot be by sense, for the object is supersensible; how, then, is it managed? We get this answer: We know the truth that the Unknowable exists, by the criterion of all truth, namely, the “inconceivability of the opposite.” But if this criterion really says anything in support of genuine certainty, it says that a pure conception of the mind, going quite beyond the literal testimony of sense, is objectively valid, in and of itself.
Manifestly, the only way of escape from this very awkward conclusion, so plainly contradictory of the prime thesis that our knowledge rests on sense alone and is confined to things of sense, is to say that inconceivability means nothing but the incapacity which limited experience begets in us — our impotence to think beyond the bounds built for us by the accumulated pressure of hereditary impressions. But here, if we would maintain the empiricist theory of knowledge in its consistent integrity, we are confronted with two difficulties: (1) How can impotence to pass the limits of experience suddenly be transformed into power to pass them and pierce to a Noumenon, even as barely existent? (2) How can our incapability of conceiving the opposite of existence for the Noumenon mean anything more than that we are so hemmed in by the massed result of our sense-impressions as to be incapable of releasing our thoughts from their mould? — that we must think as sense compels us,
