"According to the Greatest Happiness Principle, as above explained, the ultimate end, with reference to and for the sake of which all other things are desirable (whether we are considering our own good or that of other people), is an existence exempt as far as possible from pain, and as rich as possible in enjoyments, both in point of quantity and quality; the test of quality, and the rule for measuring it against quantity, being the preference felt by those who in their opportunities of experience, to which must be added their habits of self-consciousness and self-observation, are best furnished with the means of comparison. This, being, according to the utilitarian opinion, the end of human action, is necessarily also the standard of morality; which may accordingly be defined, the rules and precepts for human conduct, by the observance of which an existence such as has been described might be, to the greatest extent possible, secured to all mankind; and not to them only, but, so far as the nature of things admits, to the whole sentient creation.
Against this doctrine, however, arises another class of objectors, who say that happiness, in any form, cannot be the rational purpose of human life and action; because, in the first place, it is unattainable: and they contemptuously ask, what right hast thou to be happy? a question which Mr. Carlyle clenches by the addition, What right, a short time ago, hadst thou even to be?"
... Utilitarianism, John Stuart Mill