The origins of both economic and philosophical value theory are examined and shown to be closely related. The status of neo-classical value theory is that it is internally flawed in any attempt to describe the real world. Cost-benefit analysis as it applies to the valuation of environmental agents relies upon the claim that this neo-classical theory has a particular status in optimal welfare maximisation and, therefore, suffers the same problems of internal consistency. Economic valuation of the environment is not a (...) scientific process derived from external law but a social process relying upon social agreement. Alternatives to economic valuation are considered and may possess a more plausible social base. However, all environmental valuation is at odds with beliefs based upon the existence of objective and intrinsic values. (shrink)