The only ethical argument for positive δ? Partiality and pure time preference

I consider the plausibility of discounting for kinship, the view that a positive rate of pure intergenerational time preference is justifiable in terms of agent-relative moral reasons relating to partiality between generations. I respond to Parfit's objections to discounting for kinship, but then highlight a number of apparent limitations of this approach. I show that these limitations largely fall away when we reflect on social discounting in the context of decisions that concern the global community as a whole, such as those related to global climate change.