To inquire how far the bad effects of this deficiency have been mitigated in practice, or to what extent the moral beliefs of mankind have been vitiated or made uncertain by the absence of any distinct recognition of an ultimate standard, would imply a complete survey and criticism of past and present ethical doctrine. It would, however, be easy to show that whatever steadiness or consistency these moral beliefs have attained, has been mainly due to the tacit influence of a standard not recognised. Although the non-existence of an acknowledged first principle has made ethics not so much a guide as a consecration of men's actual sentiments, still, as men's sentiments, both of favour and of aversion, are greatly influenced by what they suppose to be the effects of things upon their happiness, the principle of utility, or as Bentham latterly called it, the greatest happiness principle, has had a large share in forming the moral doctrines even of those who most scornfully reject its authority. Nor is there any school of thought which refuses to admit that the influence of actions on happiness is a most material and even predominant consideration in many of the details of morals, however unwilling to acknowledge it as the fundamental principle of morality, and the source of moral obligation. I might go much further, and say that to all those _à priori_ moralists who deem it necessary to argue at all, utilitarian arguments are indispensable. It is not my present purpose to criticise these thinkers; but I cannot help referring, for illustration, to a systematic treatise by one of the most illustrious of them, the _Metaphysics of Ethics_, by Kant. This remarkable man, whose system of thought will long remain one of the landmarks in the history of philosophical speculation, does, in the treatise in question, lay down an universal first principle as the origin and ground of moral obligation; it is this:--'So act, that the rule on which thou actest would admit of being adopted as a law by all rational beings.' But when he begins to deduce from this precept any of the actual duties of morality, he fails, almost grotesquely, to show that there would be any contradiction, any logical (not to say physical) impossibility, in the adoption by all rational beings of the most outrageously immoral rules of conduct. All he shows is that the _consequences_ of their universal adoption would be such as no one would choose to incur.