summum bonum (Latin ‘highest good’), that in relation to which all other things have at most instrumental value (value only insofar as they are productive of what is the highest good). Philosophical conceptions of the summum bonum have for the most part been teleological in character. That is, they have identified the highest good in terms of some goal or goals that human beings, it is supposed, pursue by their very nature. These natural goals or ends have differed considerably. For the theist, this end is God; for the rationalist, it is the rational comprehension of what is real; for hedonism, it is pleasure; etc. The highest good, however, need not be teleologically construed. It may simply be posited, or supposed, that it is known, through some intuitive process, that a certain type of thing is ‘intrinsically good.’ On such a view, the relevant contrast is not so much between what is good as an end and what is good as a means to this end, as between what is good purely in itself and what is good only in combination with certain other elements (the ‘extrinsically good’). Perhaps the best example of such a view of the highest good would be the position of Moore. Must the summum bonum be just one thing, or one kind of thing? Yes, to this extent: although one could certainly combine pluralism (the view that there are many, irreducibly different goods) with an assertion that the summum bonum is ‘complex,’ the notion of the highest good has typically been the province of monists (believers in a single good), not pluralists. J.A.M.