Both intertemporal and intratemporal equity are central to the examination of policy towards climate change. However, many discussions of intertemporal issues have been marred by serious analytical errors, particularly in applying standard approaches to discounting; the errors arise, in part, from paying insufficient attention to the magnitude of potential damages, and in part from overlooking problems with market information. Some of the philosophical concepts and principles of Paper 1 are applied to the analytics and ethics of pure-time discounting and infinite-horizon models, providing helpful insights into orderings of welfare streams and obligations towards future generations. Such principles give little support for the idea of discrimination by date of birth. Intratemporal issues are central to problematic and slow-moving international discussions and are the second focus of this paper. A way forward is to cast the policy issues and analyses in a way that keeps equity issues central and embeds them in the challenge of fostering the dynamic transition to the low-carbon economy in both developed and developing countries. This avoids the trap of seeing issues primarily in terms of burden-sharing and zero-sum games – that leads to inaction and the most inequitable outcome of all.

Martin Jones has criticized my account of the methodology of experimental economics on three points: the impossibility of testing external validity claims in the laboratory, my reconstruction of external validity inferences as analogical arguments, and the distinction between laboratory and non-laboratory sciences. I defend my account here and try to eliminate some misunderstandings that may have prompted Jones’s criticism.

This critical note concerns John Broome's book Rationality through Reasoning (2013). Broome claims that rationality amounts to satisfying rational requirements as opposed to responding correctly to reasons. My critique focuses on two issues. First, I try to show that Broome's account of rational requirements, in particular his answer to the so-called ‘symmetry-problem’, presupposes that responding correctly to reasons is part of rationality. Secondly, in discussing Broome's account of reasoning I criticize his claim that first-order reasoning involves no appeal to reasons and, hence, no normative thoughts on behalf of the reasoner.