it is reasonable for a Utilitarian to praise any conduct more felicific in its tendency than what an average man would do under the given circumstanc… - Henry Sidgwick

Is it total or average happiness that we seek to make a maximum?...we foresee as possible that an increase in [population] numbers will be accompanied by a decrease in average happiness...if we take Utilitarianism to prescribe, as the ultimate end of action, happiness on the whole...it would follow that, if the additional population enjoy on the whole positive happiness, we ought to weigh the amount of happiness gained by the extra number against the amount lost by the remainder. So that, strictly conceived, the point up to which, on Utilitarian principles, population ought to be encouraged to increase, is not that at which average happiness is the greatest possible...but that at which the product formed by multiplying the number of persons living into the amount of average happiness reaches its maximum.

Now, I agree with Mill in holding that the scientific study of the structures and functions of the different governments that have actually existed in human societies cannot well be pursued in complete separation from the scientific study of other important elements of the societies in question: whether the aim of the student is to ascertain the causes of the differences in such governments or to examine their effects. But I do not think that there is any fundamental difference, in this respect, between the study of political relations and the study of economic relations, or, again, of religion, of art, of science and philosophy, as factors of social life. In each of these eases the student concentrates his attention on one element of human history which can only be partially separated from other components of the whole complex fact of social development. Experience seems to show that this kind of concentration, and consequent partial separation of historical and sociological study into special branches, is unavoidable in the division of intellectual labour which the growth of our knowledge renders necessary in a continually increasing degree.

it seems scarcely extravagant to say that, amid all the profuse waste of the means of happiness which men commit, there is no imprudence more flagrant than that of Selfishness in the ordinary sense of the term,—that excessive concentration of attention on the individual’s own happiness which renders it impossible for him to feel any strong interest in the pleasures and pains of others.