THE PROOF NOW GIVEN CONFIRMED BY EXPERIENCE. The truth I have here laid down, that Compassion is the sole non-egoistic stimulus, and therefore the only really moral one, is a strange, indeed almost incomprehensible paradox. I shall hope, therefore, to render it less extraordinary to the reader, if I show that it is confirmed by experience, and by the universal testimony of human sentiment. (1) For this purpose I shall, in the first place, state an imaginary case, which in the present investigation may serve as an _experimentum crucis_[1] (a crucial test). But not to make the matter too easy, I shall take no instance of loving-kindness, but rather a breach of lawful right, and that of the worse kind. Let us suppose two young people, Caius and Titus, to be passionately in love, each with a different girl, and that both are completely thwarted by two other men who are preferred because of certain external circumstances. They have both resolved to put their rivals out of the way, and are perfectly secure from every chance of detection, even from all suspicion. But when they come to actually prepare for the murder, each of them, after an inward struggle, draws back. They are now to give us a truthful and clear account of the reasons why they abandoned their project. As for Caius, I leave it entirely to the reader to choose what motive he likes. It may be that religions grounds checked him; for instance, the thought of the Divine Will, of future retribution, of the judgment to come, etc. Or perhaps he may say: "I reflected that the principle I was going to apply in this case would not be adapted to provide a rule universally valid for all possible rational beings; because I should have treated my rival only as a means, and not at the same time as an end." Or, following Fichte, he may deliver himself as follows: "Every human life is a means towards realising the moral law; consequently, I cannot, without being indifferent to this realisation, destroy a being ordained to do his part in effecting it."--(_Sittenlehre_, p. 373.) (This scruple, be it observed in passing, he might well overcome by the hope of soon producing a new instrument of the moral law, when once in possession of his beloved.) Or, again, he may speak after the fashion of Wollaston: "I considered that such an action would be the expression of a false tenet." Or like Hutcheson: "The Moral Sense, whose perceptions, equally with those of every other sense, admit of no final explanation, forbade me to commit such a deed." Or like Adam Smith: "I foresaw that my act would awaken no sympathy with me in the minds of the spectators." Or his language may be borrowed from Christian Wolff: "I recognised that I should thereby advance neither the work of making myself perfect, nor the same process in any one else." Or from Spinoza: "_Homini nihil utilius homine: ergo hominem interimere nolui_." (To man nothing is more useful than man: therefore