that is good (e.g., a radio is instrumentally good in order to hear music). An intrinsically valuable thing, by contrast, is worth having for itself, not as a means to something else. Intrinsic and instrumental goods do not constitute mutually exclusive categories: some things can be found to be both good (in themselves) while simultaneously being good for getting other things that have value. A prominent argument in environmental ethics, made by writers like Aldo Leopold and Holmes Rolston III, is that wild nature and healthy ecosystems have intrinsic value, prior to and apart from their instrumental value as resources for humans, and should therefore be preserved. This line of argument has been articulated further in recent years by Canadian philosopher John McMurtry within the Encyclopedia of Life Support Systems published by UNESCO. Pragmatism and contributory goodness John Dewey (1859-1952) in his book Theory of Valuation, says goodness is the outcome of ethic valuation and a continuous balancing of "ends in view". An end in view is said to be an objective potentially adopted, which may be refined or rejected based on its consistency with other objectives or as a means to objectives already held. Dewey's empiricist approach evinces absolute intrinsic value denial; i.e. not accepting intrinsic value as an inherent or enduring property of things. Instead, Dewey sees the appearance of intrinsic value as an illusory product of our continuous valuative activity as purposive beings. In addition to denying categorically that there is anything like intrinsic value, Dewey held the same position with regard to moral values - for Dewey, moral values are also based on a learning process, and are never intrinsic or absolute. Another contribution of pragmatism to value theory is the idea of contributory goods with a contributory conditionality. These have the same qualities as the good thing, but need some emergent property of a whole state-of-affairs in order to be good. For example, salt is food on its own, but is far better as part of a prepared meal. In other words, such goods are only "good" when certain conditions are met. This is in contrast to other goods, which may be considered "good" in a wider variety of situations. Kant: hypothetical and categorical goods The thinking of Immanuel Kant greatly influenced moral philosophy. He thought of moral value as a unique and universally identifiable property, as an absolute value rather than a relative value.