"That the same is the case with all the categories and principles formed from them, is apparent from this, that we cannot really define a single one of them; that is to say, we cannot render the possibility of their object intelligible without attending to the conditions of sensibility, and consequently to the form of the appearances; conditions to which these categories must be confined as to their sole objects. If this condition be taken away, all meaning, that is, all relation to the object is destroyed, and by no example can we be made to conceive what is the proper meaning of these conceptions.
"If no account be made of all the conditions of sensibility which denote them (he is speaking of the categories) as conceptions of a possible empirical use, if they be taken to be conceptions of things in general, and consequently, of transcendental use, nothing remains to be done, so far as they are concerned, but to preserve the logical functions in judgments, as the condition of the possibility of the things themselves, without being able to show in what case, their application and their object, and consequently they themselves, may, in the pure understanding, and without the intervention of sensibility, have a meaning and an objective value.
"It incontestably follows from what has been said, that pure conceptions of the understanding can never have a transcendental use, but only an empirical use; and that the principles of the pure understanding do not refer to the objects of the senses, except when the senses are in relation with the general conditions of a possible experience; but never to things in general, without relation to the way in which we may perceive them."[8]
66. Thus Kant destroys all metaphysical science, and, involved in its deplorable ruins, perish the most fundamental, most precious, and most sacred ideas of the human mind. According to him, transcendental analysis makes us see that the understanding can never pass the limits of sensibility, the only limits within which objects are given to us in intuition. These principles which were regarded as eternal pillars of the scientific edifice sink into empty forms, into words without meaning, so soon as they rise from the sphere of sensibility.
Ontology, with its transcendental doctrines, avails not in the eyes of the German philosopher to explain the nature and origin of things. "These principles," he says, "are simply principles of the exposition of phenomena; and the proud name of an ontology which pretends to give an a priori, synthetic cognition of things, in a systematic doctrine, for example, the principle of causality, ought to be replaced by the modest denomination of simple analysis of the pure understanding."
67. It would be hard to find a more noxious doctrine. What is left to the human mind when all means of rising from the sensible sphere are taken away? To what is our understanding reduced, if its most fundamental ideas, and its noblest principles can teach nothing concerning the nature of things? If the corporeal world is for us nothing but a collection of sensible phenomena, beyond which we can know nothing, our cognitions have nothing real, they are all purely subjective; the soul lives on illusions, and vanishes with its imaginary creations, to which there is nothing to correspond in reality. Space is but a subjective form; time is but a subjective form; pure ideas are empty conceptions, and all in us is subjective. We know nothing of objects, we are totally ignorant of what is; we know only what appears. This is pure skepticism; assuredly it was not necessary to consume so much time in analytical investigations to get thus far. The doctrine of Kant presents no extravagance so outrageous, no error so hideous, as the works of Fichte, Schelling, and Hegel; but it contains the germ of the greatest extravagance, and of the most fatal errors. He has made a philosophical revolution, which some have incautiously deemed a progress; but doubtless they did not detect the skepticism it contains, which is the more dangerous, the more it is enveloped in analytical forms.
68. Notwithstanding the importance justly attached to the refutation of the German philosopher's errors, I do not deem it necessary to combat his doctrines step by step; this system of refutation labors under the serious objection that it gives little satisfaction to the reader, who seems to see one edifice torn down, but not replaced by another. I consider it more useful carefully to examine questions as they arise in the order of their subjects, to establish my opinion as best I can, and there to refute Kant's errors as I find them obstructing the march of truth. It is ordinarily very easy to say what a thing is not; but it is not so easy to say what it is; and it is not proper that the advocates of sound doctrine should be charged with impugning false doctrines, and not caring to expose their own. We believe that in these matters sound philosophy may be presented to the light of the day struggling against error, and that it ought not to rest satisfied with being the instrument of war to overthrow its adversary, but that it should aspire to found a noble and enduring edifice upon the very site the other occupied.
The minds of men are not satisfied with simple refutations; they desire to have a doctrine substituted in the place of the one impugned. Whoever impugns, denies; and the understanding is not satisfied with negations; it wants affirmation, for it cannot live without positive truth.