What modi of the pure conceptions of reason these transcendental ideas are will be fully exposed in the following chapter. They follow the guiding thread of the categories. For pure reason never relates immediately to objects, but to the conceptions of these contained in the understanding. In like manner, it will be made manifest in the detailed explanation of these ideas—how reason, merely through the synthetical use of the same function which it employs in a categorical syllogism, necessarily attains to the conception of the absolute unity of the thinking subject—how the logical procedure in hypothetical ideas necessarily produces the idea of the absolutely unconditioned in a series of given conditions, and finally—how the mere form of the disjunctive syllogism involves the highest conception of a being of all beings: a thought which at first sight seems in the highest degree paradoxical. An objective deduction, such as we were able to present in the case of the categories, is impossible as regards these transcendental ideas. For they have, in truth, no relation to any object, in experience, for the very reason that they are only ideas. But a subjective deduction of them from the nature of our reason is possible, and has been given in the present chapter. It is easy to perceive that the sole aim of pure reason is the absolute totality of the synthesis on the side of the conditions, and that it does not concern itself with the absolute completeness on the Part of the conditioned. For of the former alone does she stand in need, in order to preposit the whole series of conditions, and thus present them to the understanding à priori. But if we once have a completely (and unconditionally) given condition, there is no further necessity, in proceeding with the series, for a conception of reason; for the understanding takes of itself every step downward, from the condition to the conditioned. Thus the transcendental ideas are available only for ascending in the series of conditions, till we reach the unconditioned, that is, principles. As regards descending to the conditioned, on the other hand, we find that there is a widely extensive logical use which reason makes of the laws of the understanding, but that a transcendental use thereof is impossible; and that when we form an idea of the absolute totality of such a synthesis, for example, of the whole series of all future changes in the world, this idea is a mere ens rationis, an arbitrary fiction of thought, and not a necessary presupposition of reason. For the possibility of the conditioned presupposes the totality of its conditions, but not of its consequences. Consequently, this conception is not a transcendental idea—and it is with these alone that we are at present occupied.