But the mistake of Kant lies in not having well analyzed the concepts of pleasure, of happiness and of the useful, and in having thought that he could free himself from them, by placing them among another set of principles, which he called _hypothetical_ imperatives and opposed to the _categoric. _ We know that the imperative of those concepts is not less categoric than that of morality: it is a true imperative, not to be confounded with the knowledge of experience, metaphorically called imperative, because it assumes the appearance of a technique dealing with the practical. Kant was to some extent aware of this, for he sub-distinguishes the hypothetical imperatives into _problematical_ and _assertorial._ The first of these are technical and give rise to maxims of _cleverness_ (_Geschicklichkeit_); the second are _pragmatic_ and consist of maxims of _prudence._ Observe the difficulties in which he becomes involved, through not wishing to recognize the autonomous character of these imperatives compared with the moral imperatives, that is to say, the categoricity of both. The imperatives of prudence and of happiness are concerned (he says) "with an end which can be assumed as real among all rational beings (in so far as the imperatives can be applied to them in their quality of dependent beings); and, therefore, an intention, which not only they _may_ possess, but which it is assumed with certainty that they _do_ possess, according to a necessity of nature, which is the intention of happiness." We should therefore conclude that they are concerned with an end not less serious than that of morality. But Kant perceives the poison in the argument and strives to turn them again into imperatives concerning means: "ability" (he continues) "in the choice of the means of one's own well-being, may be called _prudence;_ therefore the imperative relating to the choice of the means for one's own happiness, namely the precept of prudence, is always hypothetical; the action is ordered, not absolutely, but only as means for another purpose." It is clear that to be able to call that knowledge or ability "prudence" is not sufficient to change the imperative of happiness into mere ability and knowledge. Kant perceives this also: "If it were easy to give a definite concept of happiness, the imperatives of prudence would altogether coincide with those of ability and would also be analytic. For it would be said in the one case as in the other, that he who wishes the end also wishes (necessarily, in conformity with reason) the only means for the purpose within his power. The concept of happiness is unfortunately so indeterminate, that although every one wishes to attain to it, he is nevertheless unable ever to say definitely and in accordance with himself exactly what he desires and wishes. The reason is that the elements which belong to the concept of happiness are all empirical and must therefore all be taken from experience; quired an absolute