The two qualities which seem to be most required in first principles of ethics are, (1) that they should afford a real explanation of the facts, (2) that they should inspire the mind,--should harmonize, strengthen, settle us. We can hardly estimate the influence which a simple principle such as 'Act so as to promote the happiness of mankind,' or 'Act so that the rule on which thou actest may be adopted as a law by all rational beings,' may exercise on the mind of an individual. They will often seem to open a new world to him, like the religious conceptions of faith or the spirit of God. The difficulties of ethics disappear when we do not suffer ourselves to be distracted between different points of view. But to maintain their hold on us, the general principles must also be psychologically true--they must agree with our experience, they must accord with the habits of our minds. When we are told that actions are right or wrong only in so far as they tend towards happiness, we naturally ask what is meant by 'happiness.' For the term in the common use of language is only to a certain extent commensurate with moral good and evil. We should hardly say that a good man could be utterly miserable (Arist. Ethics), or place a bad man in the first rank of happiness. But yet, from various circumstances, the measure of a man's happiness may be out of all proportion to his desert. And if we insist on calling the good man alone happy, we shall be using the term in some new and transcendental sense, as synonymous with well-being. We have already seen that happiness includes the happiness of others as well as our own; we must now comprehend unconscious as well as conscious happiness under the same word. There is no harm in this extension of the meaning, but a word which admits of such an extension can hardly be made the basis of a philosophical system. The exactness which is required in philosophy will not allow us to comprehend under the same term two ideas so different as the subjective feeling of pleasure or happiness and the objective reality of a state which receives our moral approval. Like Protarchus in the Philebus, we can give no answer to the question, 'What is that common quality which in all states of human life we call happiness? which includes the lower and the higher kind of happiness, and is the aim of the noblest, as well as of the meanest of mankind?' If we say 'Not pleasure, not virtue, not wisdom, nor yet any quality which we can abstract from these'--what then? After seeming to hover for a time on the verge of a great truth, we have gained only a truism.