Pablo Stafforini

Esteemed philosopher John Broome avoids the familiar ideological stances on climate change policy and examines the issue through an invigorating new lens. As he considers the moral dimensions of climate change, he reasons clearly through what universal standards of goodness and justice require of us, both as citizens and as governments. His conclusions—some as demanding as they are logical—will challenge and enlighten. Eco-conscious readers may be surprised to hear they have a duty to offset all their carbon emissions, while policy makers will grapple with Broome’s analysis of what if anything is owed to future generations. From the science of greenhouse gases to the intricate logic of cap and trade, Broome reveals how the principles that underlie everyday decision making also provide simple and effective ideas for confronting climate change. Climate Matters is an essential contribution to one of the paramount issues of our time.

Scientific and technological progress might change people’s capabilities or incentives in ways that would destabilize civilization. For example, advances in DIY biohacking tools might make it easy for anybody with basic training in biology to kill millions; novel military technologies could trigger arms races in which whoever strikes first has a decisive advantage; or some economically advantageous process may be invented that produces disastrous negative global externalities that are hard to regulate. This paper introduces the concept of a vulnerable world: roughly, one in which there is some level of technological development at which civilization almost certainly gets devastated by default, i.e. unless it has exited the “semi-anarchic default condition”. Several counterfactual historical and speculative future vulnerabilities are analyzed and arranged into a typology. A general ability to stabilize a vulnerable world would require greatly amplified capacities for preventive policing and global governance. The vulnerable world hypothesis thus offers a new perspective from which to evaluate the risk-benefit balance of developments towards ubiquitous surveillance or a unipolar world order.

Longtermists claim that what we ought to do is mainly determined by how our actions might affect the very long-run future. A natural objection to longtermism is that these effects may be nearly impossible to predict -- perhaps so close to impossible that, despite the astronomical importance of the far future, the expected value of our present actions is mainly determined by near-term considerations. This paper aims to precisify and evaluate one version of this epistemic objection to longtermism. To that end, I develop two simple models for comparing "longtermist" and "neartermist" interventions, incorporating the idea that it is harder to make a predictable difference to the further future. These models yield mixed conclusions: if we simply aim to maximize expected value, and don't mind premising our choices on minuscule probabilities of astronomical payoffs, the case for longtermism looks robust. But on some prima facie plausible empirical worldviews, the expectational superiority of longtermist interventions depends heavily on these "Pascalian" probabilities. So the case for longtermism may depend either on plausible but non-obvious empirical claims or on a tolerance for Pascalian fanaticism.