Henry Sidgwick

But […] [t]he introduction of these notions into Ethics is liable to bring with it a fundamental confusion between “what is” and “what ought to be”, destructive of all clearness in ethical reasoning

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 …

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 …

Plato’s reason for claiming that the life of the Philosopher has more pleasure than that of the Sensualist is palpably inadequate.

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 circumstances

A universal refusal to propagate the human species would be the greatest of conceivable crimes from a Utilitarian point of view

In short, if a certain quality of human Life is that which is ultimately desirable, it must belong to human Life regarded on its psychical side, or, briefly, Consciousness.

the time at which a man exists can’t affect the value of his happiness from a universal point of view; so the interests of posterity must concern a utilitarian as much as those of his contemporaries

it seems arbitrary and unreasonable to exclude from the end, as so conceived, any pleasure of any sentient being.

We have next to consider who the “all” are, whose happiness is to be taken into account. Are we to extend our concern to all the beings capable of pleasure and pain whose feelings are affected by our conduct?

Each person is morally obliged to regard the good of anyone else as much as his own good, except when he judges it to be less, when impartially viewed, or less certainly knowable or attainable by him.

The good of any one individual is of no more importance, from the point of view...of the Universe, than the good of any other; unless, that is, there are special grounds for believing that more good is likely to be realized in the one case …