In the same way, ethics may be brought into one kind of contact with psychology. Ethics, like logic, may be supposed to presuppose and to deal with a certain inflexible scheme of requirements, a world of moral order governed by invariable or universal law; an eternal kingdom of right, existing independently of human wills, but to be learned and followed out in uncompromising obedience. As against this supposed absolute order, psychology may be said to show the genesis of the idea of obligation and duty, the growth of the authority of conscience, the formation of ideals, the relativity of moral ideas. Here also it may reach this conclusion, by a more external or a more internal mode of argument. It may try to show, in other words, that circumstances give rise to these forms of estimating conduct, or it may argue that they are a necessary development in the human being, constituted as he is. It may again be doubted whether this is properly called psychology. Yet its purport seems ultimately to be that the objective order is misconceived when it is regarded as an external or quasi-physical order: as a law written up and sanctioned with an external authority—as, in Kant’s words, a heteronomy. If that order is objective, it is so because it is also in a sense subjective: if it is above the mere individuality of the individual, it is still in a way identical with his true or universal self-hood. Thus “psychological” here means the recognition that the logical and the moral law is an autonomy: that it is not given, but though necessary, necessary by the inward movement of the mind. The metaphor of law is, in brief, misleading. For, according to a common, though probably an erroneous, analysis of that term, the essence of a law in the political sphere is to be a species of command. And that is rather a one-sidedly practical or aesthetic way of looking at it. The essence of law in general, and the precondition of every law in special, is rather uniformity and universality, self-consistency and absence of contradiction: or, in other words, rationality. Its essential opposite—or its contradiction in essence—is a privilege, an attempt at isolating a case from others. It need not indeed always require bare uniformity—require i.e. the same act to be done by different people: but it must always require that every thing within its operation shall be treated on principles of utter and thorough harmony and consistency. It requires each thing to be treated on public principles and with publicity: nothing apart and mere singular, as a mere incident or as a world by itself. Differently it may be treated, but always on grounds of common well-being, as part of an embracing system.