Nonuse values are a potentially very important, but controversial, aspect of the economic valuation of the environment. Since no use is envisaged by the individual, a degree of altruism appears to be the driving force behind nonuse values. Whilst much of the controversy has focused upon measurement issues associated with the contingent valuation method, this paper concentrates on the underlying motivations, whether ethical or economic, that form the basis for such values. Some fundamental aspects of defining and quantifying economic nonuse (...) values are considered, and possible motives for attributing value to the environment are analysed, making a clear distinction between 'selfish' altruism and 'selfless' altruism. The difference has crucial implications for economic valuation and for assessing individuals' willingness to pay for environmental quality. The concept of Safe Minimum Standards is introduced as a means of supplementing purely economic methodology to incorporate ethical concerns into decision making. (shrink)