[21] It is nothing but one and the same will, which at one time is called sensuous desire, when it is stimulated by acts of judgment, formed in consequence of perceptions of the senses; and which at another time is called rational desire (_i.e._ desire of the reason), when the mind forms acts of judgment about its own proper ideas, independently of the thoughts belonging to, and mixed up with, the senses; which thoughts are the causes of the mind's tendencies.... That these two diverse propensities of the will should be regarded as two distinct desires is occasioned by the fact that very often the one is opposed to the other, because the intention, which is built up by the mind on the foundation of its own proper perceptions, does not always agree with the thoughts which are suggested to the mind by the body's disposition; whereby it (the mind) is often constrained to will something, while its reason makes it choose something different.--(_Translator_.) CHAPTER V. ON THE LEADING PRINCIPLE OF THE KANTIAN ETHICS. After having tested in the preceding chapter the actual basis of Kant's Ethics, I now turn to that which rests on it--his =leading principle of Morals=. The latter is very closely connected with the former; indeed, in a certain sense, they both grew up together. We have seen that the formula expressing the principle reads as follows: "Act only in accordance with that precept which you can also wish should be a general law for all rational beings." It is a strange proceeding for a man, who _ex hypothesi_ is seeking a law to determine what he should do, and what he should leave undone, to be instructed first to search for one fit to regulate the conduct of all possible rational beings; but we will pass over that. It is sufficient only to notice the fact that in the above guiding rule, as put forth by Kant, we have obviously not reached the moral law itself, but only a finger-post, or indication where it is to be looked for. The money, so to say, is not yet paid down, but we hold a safe draft for it. And who, then, is the cashier? To say the truth at once: a paymaster in this connection surely very unexpected, being neither more nor less than =Egoism=, as I shall now demonstrate.