Concerning the second point, Sir Leslie Stephen warns us (_Science of Ethics_, p. 437) that every attempt so to state the ethical principle that disobedience will be "unreasonable" is "doomed to failure in a world which is not made up of working syllogisms." And for the other two points Professor Sorley (_Ethics of Naturalism_, p. 42) tells us that "It is difficult ... to offer any consideration fitted to convince the individual that it is reasonable for him to seek the happiness of the community rather than his own"; while Mr. Benjamin Kidd asserts that "the interests of the individual and those of the social organism are not either identical or capable of being reconciled, as has been necessarily assumed in all those systems of ethics which have sought to establish a naturalistic basis of conduct. The two are fundamentally and inherently irreconcilable, and a large proportion of the existing individuals at any time have ... no personal interest whatever in the progress of the race, or in the social development we are undergoing." It has already been said that however difficult it may be to establish the precise relationship between reason and ethical commands, such a connection must be assumed, whether we base our ethics on naturalistic or supernaturalistic considerations. And it cannot be denied by anyone to-day that a causal relation must exist between actions and their consequences, whether those causal consequences be of the natural and non-moral kind, or of the more definitely moral order such as exists in the shape of social approval and disapproval. And if we once grant that, then it seems quite allowable to assume that provided a man perceives the reason underlying moral judgments, and also the justification for the sense of approval and disapproval expressed, we have as much reason for calling his conduct reasonable or unreasonable as we have for applying the same terms to a man's behaviour in dressing in view of the variations of the temperature. Consequently, while I agree that _in the present state of knowledge_ it is impossible in all cases to demonstrate that immoral conduct is irrational in the sense that it would be unreasonable to refuse assent to a mathematical proposition, there seems no justification for regarding such a state of things as of necessity permanent. If a scientific system of ethics consists in formulating rules for the profitable guidance of life, not only does their formulation presuppose a certain constancy in the laws of human nature and of the world in general, but the assumption is also involved that one day it may be possible to give to moral laws the same precision that now is attached to physiological laws and to label departure from them as "unreasonable" in a very real sense of the word.