Jeremy Bentham, answered from the texts and cited to the page.
The value of a pleasure or pain is reckoned by its intensity, duration, certainty, propinquity, fecundity, purity, and, across persons, its extent.1 The reckoning is a rank-ordering of consequences, not the assignment of cardinal numbers; I never set a figure upon intensity, which is idiosyncratic. "Every individual to count for one, nobody for more than one." On the aggregation of interests the doctrine forbids nothing in advance: the vital interests of a few may outweigh the lesser interests of many, and the like interests of many may outweigh those of a few.
This is at once the engine of reform and the place where the gravest objection lodges, and the texts do not finally close the question.23
Just so is it with pains: and thence with exemptions from pains. The magnitude of the pleasure derived from the source in question, supposing it present, being given—as also the value to which it is reduced by distance as above—the value of it is subjected to a further reduction by whatever it is deficient in respect of certainty: suppose, then, that at the time for its being received, as above, the probability,…Legislator of the World, Writings on Codification, Law, and Education, pp. 251–252
The money which a man is robbed of, of what use, had he not [been] robbed of it, would it have been to himself or any one, unless it be by adding in some shape or other to the sum of his or some one else's pleasures, or substracting in some shape or other from his or some one else's pains?Not Paul, But Jesus Vol III, Doctrine, pp. 18–19
You may add to it: but you will not double it. Cover him with ribbons, as, at the expense of his starving subjects, some of the King of England's servants are covered with gold lace, till the colour of the coat is scarcely visible—add even money in proportion—still will it be matter of doubt whether the quantity of pleasure in his mind will be double the quantity existing in the mind of the labouring man…Legislator of the World, Writings on Codification, Law, and Education, pp. 253–254
The interpersonal comparison of intensity is genuinely hard; Bentham appealed to rank-ordering and to the burthens likely to follow, not to a measuring-rod. Rawls (A Theory of Justice, 1971) made the failure to respect the distinction between persons the founding objection of post-utilitarian liberalism. Bentham held that ruling out nothing a priori is the strength of the doctrine; the worry about the sacrificed minority is not dissolved by the texts.