It may be desirable to add a word about the second of the three moral criteria put forward by Kant--the rule Use humanity whether in thine own person or in that of any other always as an end, never as a means only. It is the principle less frequently insisted on in Kant's own writings, and its relation to the other is not very precisely determined. He uses it chiefly to prove the immorality of suicide and of sexual transgression. There can be no question of the deep moral significance of the principle, but it is too vague to be really of any use as a moral criterion without knowledge of a kind which cannot be extracted out of the formula itself. We must know what is the true end of human life before we can tell whether a certain course of conduct does or does not involve treating humanity only as a means. Now Kant (as we have seen) only recognizes two ends in human life--one primary, i.e. Morality, the other secondary, i.e. happiness. On Kant's view of Free-will it is impossible to make another man immoral or less moral. Hence it would seem that he has no right to condemn conduct towards another for any other reason than its interference with his other end--happiness. And this is clearly not always done by the kind of conduct which he has in mind. Nor, even if this consideration be waived, can he show that the conduct which he condemns involves using the body of another, or one's own, as a means, any more than much conduct which no one could describe as immoral. I am using a porter's body as a means when I employ him to carry trunks for me, and there is nothing immoral in my doing so. I am not using him only as a means, if I pay him for his work and treat him as a moral being no less entitled to share in all the true goods of life than myself. Kant never said anything so absurd (though he is constantly cited as doing so) as that we should never use humanity as a means, but only that we should never use it as a means without using it also as an end, and it is impossible (apart from some conception of a concrete end or good of human life)to show that sexual immorality might not be equally compatible with a like recognition of others' claims. We should only have to insist on just and considerate treatment of those who have been called the priestesses of humanity^[108]. The one kind of exchange of services is, on Kant's premisses, exactly on a level with the other. Kant's real feeling was no doubt that the conduct in question was inconsistent with a true ideal of the relations between man and woman, but it was impossible for him to prove that inconsistency so long as he narrowed his conception of the ideal human life down to the performance of social duty on the one hand and the indiscriminate enjoyment of pleasure on the other. It is not the treating of humanity as a means that strikes us as wrong (for that might quite well be compatible with recognizing it also as an end), but the treating of humanity as a means in this particular way, as a means to such and such a kind of sensual pleasure, to such and such an end in which Reason can find no value. It is only because we have judged already that such treatment is a degradation of humanity that we pronounce it to be using humanity only as a means.(Bk. 1 Ch. 5 § 6 ¶ 1)

Once again, we see the impossibility of reducing moral judgements to a merely intellectual, non-moral principle; of getting a criterion out of mere formal conceptions, which take no account of the content or intended consequences on which depends all the morality or the immorality of our actions. Mere universality or freedom of contradiction is no test of goodness or badness. The judgement of value cannot be reduced to any other sort of judgement--a judgement of formal consistency or a judgement as to the relation between ends and means, which takes no account of the character of those ends. It is only in estimating the value of an end that the moral Reason really comes into play. Abstract the form of the law from the matter of it, and there is nothing left on which a judgement of value can be passed. A rule of action is not moral because it is consistent, unless it consistently conduces to an end in which Reason can recognize value; neither is the making of humanity a means immoral unless the end to which it is a means be one which Reason refuses to recognize as part of the true end for man. The non-recognition of this principle involved Kant in the absurdity of gravely questioning whether it was lawful to cut one's hair, and of solemnly pronouncing the conduct of a woman who cuts off her hair to sell it--irrespectively of the motives for which she wants money--not altogether devoid of blame^[109]. Such a verdict will probably fail to commend itself to readers of Mr. Marion Crawford's touching Cigarette-maker's Romance.(Bk. 1 Ch. 5 § 6 ¶ 2)