This descending to popular notions is certainly very commendable, if the ascent to the principles of pure reason has first taken place and been satisfactorily accomplished.  This implies that we first found Ethics on Metaphysics, and then, when it is firmly established, procure a hearing for it by giving it a popular character.  But it is quite absurd to try to be popular in the first inquiry, on which the soundness of the principles depends.  It is not only that this proceeding can never lay claim to the very rare merit of a true philosophical popularity, since there is no art in being intelligible if one renounces all thoroughness of insight; but also it produces a disgusting medley of compiled observations and half-reasoned principles.  Shallow pates enjoy this because it can be used for every-day chat, but the sagacious find in it only confusion, and being unsatisfied and unable to help themselves, they turn away their eyes, while philosophers, who see quite well through this delusion, are little listened to when they call men off for a time from this pretended popularity, in order that they might be rightfully popular after they have attained a definite insight.

We need only look at the attempts of moralists in that favourite fashion, and we shall find at one time the Special constitution of human nature (including, however, the idea of a rational nature generally), at one time perfection, at another happiness, here moral sense, there fear of God, a little of this, and a little of that, in marvellous mixture, without its occurring to them to ask whether the principles of morality are to be sought in the knowledge of human nature at all (which we can have only from experience); and, if this is not so, if these principles are to be found altogether a priori free from everything empirical, in pure rational concepts only, and nowhere else, not even in the smallest degree; then rather to adopt the method of making this a separate inquiry, as pure practical philosophy, or (if one may use a name so decried) as metaphysic of morals, [Footnote:  Just as pure mathematics are distinguished from applied, pure logic from applied, so if we choose we may alse distinguish pure philosophy of morals (metaphysic) from applied (viz. applied to human nature).  By this designation we are also at once reminded that moral principles are not based on properties of human nature, but must subsist a priori of themselves while from such principles practical rules must be capable of being deduced for every rational nature, and accordingly for that of man.] to bring it by itself to completeness, and to require the public, which wishes for popular treatment, to await the issue of this undertaking.