A special and more abstract form of the same theory is presented in the dictum of Kant--'act in such a way that your conduct might be a law to all beings.' 4. It is contended, that the human mind possesses an intuition or instinct, whereby we feel or discern at once the right from the wrong; a view termed the doctrine of the Moral Sense, or Moral Sentiment. Besides being supported by numerous theorizers in Ethics, this is the prevailing and popular doctrine; it underlies most of the language of moral suasion. The difficulties attending the stricter interpretation of it have led to various modes of qualifying and explaining it, as will afterwards appear. Shaftesbury and Hutcheson are more especially identified with the enunciation of this doctrine in its modern aspect. 5. It was put forth by Mandeville that Self-interest is the only test of moral rightness. Self-preservation is the first law of being; and even when we are labouring for the good of others, we are still having regard to our own interest. 6. The theory called, Utility, and Utilitarianism, supposes that the well-being or happiness of mankind is the sole end, and ultimate standard of morality. The agent takes account both of his own happiness and of the happiness of others, subordinating, on proper occasions, the first to the second. This theory is definite in its opposition to all the others, but admits of considerable latitude of view within itself. Stoicism and Epicureanism, are both included in its compass. The two last-named theories--Self-Interest, and Utility or the Common Well-Being, have exclusive regard to the consequences of actions; the others assign to consequences a subordinate position. The terms External and Dependent are also used to express the reference to Happiness as the end: Internal and Independent are the contrasting epithets. II. Ethical Theory embraces certain questions of pure PSYCHOLOGY. 1. The Psychological nature of Conscience, the Moral Sense, or by whatever name we designate the faculty of distinguishing right and wrong, together with the motive power to follow the one and eschew the other. That such a faculty exists is admitted. The question is, what is its place and origin in the mind? On the one side, Conscience is held to be a _unique_ and ultimate power of the mind, like the feeling of Resistance, the sense of Taste, or the consciousness of Agreement. On the other side, Conscience is viewed as a growth or derivation from other recognized properties of the mind. The Theory of the Standard (4) called the doctrine of the Moral Sense, proceeds upon the first view; on that theory, the Standard and the Faculty make properly but one question. All other theories are more or less compatible with the composite or derivative nature of Conscience; the supporters of Utility, in particular, adopt this alternative.