The Philosophical Review/Volume 1/Summary: Fonsegrive - L'inconnaisable dans la philosophic moderne
According to Positivism, only facts and laws are knowable, there being neither substances nor causes, hence neither bodies, souls, nor God. But since the observer sees only a narrow field of events and yet feels that there must be an immense mass of phenomena outside of the reach of consciousness, in the past and in the future, the domain of the unknowable is very large. On the Kantian hypothesis, the physical mystery of Positivism disappears, the constancy of natural laws is vouchsafed, but a metaphysical mystery arises. It is impossible to show whether anything objective corresponds to these mental forms. The existence as well as the essence of the soul, the external world and God cannot be known. The realm of the unknowable is impenetrable by reason; faith alone is left us here.
Had Criticism succeeded in overthrowing Empiricism, Kant would be right. But his hypothesis is weak and unintelligible. What can an innate idea be before consciousness? A thought before thinking! Say that these ideas mean mental laws. Then you must hypostasize a subject as bearer of these laws. Then the theory contradicts itself, for one of its conclusions makes the existence of the mind problematical. If, however, you deny the reality of the mind and regard the a priori forms as mere abstractions resulting from mental analysis, what follows? Either an idealistic theory according to which everything is knowable, since everything is idea, and against which consciousness protests; or a dogmatism which holds that our ideas represent something, that they are in consciousness a product whose factors must be sought outside of it. Hence these laws will have an objective validity, and we are justified in constructing a truly scientific metaphysics.
F. adopts this latter view. Neither the existence nor the essence of objects is unknown to us. The existence of the soul, the world, and God is known to us, the essence of these partially knowable by the effects which they produce in us and which consist in thoughts and perceptions. To God we may ascribe as qualities the effects produced by him in the world; among these we enroll consciousness and thought. However great the sphere of the unknowable remains for such a philosophy as this, the knowledge it yields is sufficient for our guidance.