The Critique of Practical Reason [77]
to ascribe all possible perfections to the Author of the world, but these are not strict logical inferences in which we can pride ourselves on our insight, but only permitted conclusions in which we may be indulged and which require further recommendation before we can make use of them. On the path of empirical inquiry then (physics), the conception of God remains always a conception of the perfection of the First Being not accurately enough determined to be held adequate to the conception of Deity. (With metaphysic in its transcendental part nothing whatever can be accomplished.) When I now try to test this conception by reference to the object of practical reason, I find that the moral principle admits as possible only the conception of an Author of the world possessed of the highest perfection. He must be omniscient, in order to know my conduct up to the inmost root of my mental state in all possible cases and into all future time; omnipotent, in order to allot to it its fitting consequences; similarly He must be omnipresent, eternal, etc. Thus the moral law, by means of the conception of the summum bonum as the object of a pure practical reason, determines the concept of the First Being as the Supreme Being; a thing which the physical (and in its higher development the metaphysical), in other words, the whole speculative course of reason, was unable to effect. The conception of God, then, is one that belongs originally not to physics, i.e., to speculative reason, but to morals. The same may be said of the other conceptions of reason of which we have treated above as postulates of it in its practical use. In the history of Grecian philosophy we find no distinct traces of a pure rational theology earlier than Anaxagoras; but this is not because the older philosophers had not intelligence or penetration enough to raise themselves to it by the path of speculation, at least with the aid of a thoroughly reasonable hypothesis. What could have been easier, what more natural, than the thought which of itself occurs to everyone, to assume instead of several causes of the world, instead of an indeterminate degree of perfection, a single rational cause having all perfection? But the evils in the world seemed to them to be much too serious objections to allow them to feel themselves justified in such a hypothesis. They showed intelligence and penetration then in this very point, that they did not allow themselves to adopt it, but on the contrary looked about amongst natural causes to see if they could not find in them the qualities and power required for a First Being. But when this acute people had advanced so far in their investigations of nature as to treat even moral questions philosophically, on which other nations had never done anything but talk, then first they found a new and practical want, which did not fail to give definiteness to their conception of the First Being: and in this the speculative reason played the part of spectator, or at best had the merit of embellishing a conception that had not grown on its own ground, and of applying a series of confirmations from the study of nature now brought forward for the first time, not indeed to strengthen the authority of this conception (which was already established), but rather to make a show with a supposed discovery of theoretical reason.
From these remarks, the reader of the Critique of Pure Speculative Reason will be thoroughly convinced how highly necessary that laborious deduction of the categories was, and how fruitful for theology and morals. For if, on the one hand, we place them in pure understanding, it is by this deduction alone that we can be prevented from regarding them, with Plato, as innate, and founding on them extravagant pretensions to theories of the supersensible, to which we can see no end, and by which we should make theology a magic lantern of chimeras; on the other hand, if we regard them as acquired, this deduction saves us from restricting, with Epicurus, all and every use of them, even for practical purposes, to the objects and motives
From these remarks, the reader of the Critique of Pure Speculative Reason will be thoroughly convinced how highly necessary that laborious deduction of the categories was, and how fruitful for theology and morals. For if, on the one hand, we place them in pure understanding, it is by this deduction alone that we can be prevented from regarding them, with Plato, as innate, and founding on them extravagant pretensions to theories of the supersensible, to which we can see no end, and by which we should make theology a magic lantern of chimeras; on the other hand, if we regard them as acquired, this deduction saves us from restricting, with Epicurus, all and every use of them, even for practical purposes, to the objects and motives