I think “utilitarian” has picked up too many different meanings for us to use the word without saying which meaning we mean. I see people using it in (at least) 5 different senses.
Someone who prioritizes function over form, which might be the most common lay definition. (See e.g. Wiktionary defining “utilitarian” as an adjective meaning “practical and functional, not just for show”.)
Someone trying to maximize a utility function or welfare function, whatever that function’s form. (I mentally call this “utilityfunctionarianism” to distinguish it from the other meanings.)
Someone trying to maximize an additively separable utility function or welfare function, i.e. someone who defines social utility as a weighted sum or average of each person’s utility. (Ken Binmore uses this definition in his Game Theory and the Social Contract and says it’s a “not uncommon definition”.)
Someone trying to maximize an unweighted sum or average of each person’s utility, i.e. an egalitarian utility maximizer. (Which seems to be the meaning being used here, and sometimes elsewhere on LW, e.g. here.)
A Benthamite, which (I think?) is close to meaning 4, but with “utility” operationalized as “happiness”.
I think “utilitarian” has picked up too many different meanings for us to use the word without saying which meaning we mean. I see people using it in (at least) 5 different senses.
Someone who prioritizes function over form, which might be the most common lay definition. (See e.g. Wiktionary defining “utilitarian” as an adjective meaning “practical and functional, not just for show”.)
Someone trying to maximize a utility function or welfare function, whatever that function’s form. (I mentally call this “utilityfunctionarianism” to distinguish it from the other meanings.)
Someone trying to maximize an additively separable utility function or welfare function, i.e. someone who defines social utility as a weighted sum or average of each person’s utility. (Ken Binmore uses this definition in his Game Theory and the Social Contract and says it’s a “not uncommon definition”.)
Someone trying to maximize an unweighted sum or average of each person’s utility, i.e. an egalitarian utility maximizer. (Which seems to be the meaning being used here, and sometimes elsewhere on LW, e.g. here.)
A Benthamite, which (I think?) is close to meaning 4, but with “utility” operationalized as “happiness”.
So it’s a fuzzy term.
An argument elsewhere on LW reminds me of a 6th meaning for “utilitarian”: a synonym for “consequentialist”.