I discuss three families of methodologies that could be used to assign values to the normative parameters relevant to social discounting in welfare economics generally, and climate economics more specifically. First, I argue that in particular circumstances, there cannot be philosophical argumentation for normative questions; specifically, this occurs when the particular values being sought are both non-critical and from a quantitative range. Second, I argue that social preferences are insufficient if we take the problem to be normative and that proposals (...) for informed social preferences face significant challenges in implementation. Finally, I argue in favour of expert elicitation for experts in welfare economics, construed as those who understand the theoretical implications of adopting particular judgments. Those who understand the theoretical implications of adopting particular judgments will be better placed to develop coherent social plans while integrating relevant empirical data. (shrink)

The empirically documented fact is that people’s preferences are time -biased. The main aim of this paper is to analyse in which sense do time -biases violate the requirements of rationality, as many authors assume. I will demonstrate that contrary to many influential views in psychology, economy and philosophy it is very difficult to find why the bias toward the near violates the requirements rationality. I will also show why the bias toward the future violates the requirements of rationality in (...) a very basic sense. (shrink)