Hyemin Han

I draw on neurobiological evidence to defend the rationalist thesis that moral judgments are essentially dependent on reasoning, not emotions (conceived as distinct from inference). The neuroscience reveals that moral cognition arises from domain-general capacities in the brain for inferring, in particular, the consequences of an agent’s action, the agent’s intent, and the rules or norms relevant to the context. Although these capacities entangle inference and affect, blurring the reason/emotion dichotomy doesn’t preferentially support sentimentalism. The argument requires careful consideration of the empirical evidence (from neuroimaging to psychopathology) and philosophical analysis of the commitments of rationalism versus sentimentalism in ethics.

Are philosophical arguments as effective as narratives in influencing charitable giving and attitudes toward it? In four experiments, we exposed online research participants to either philosophical arguments in favor of charitable giving, a narrative about a child whose life was improved by charitable donations, both the narrative and the argument, or a control text (a passage from a middle school physics text or a description of charitable organizations). Participants then expressed their attitudes toward charitable giving and were either asked how much they would hypothetically donate if given $10 (Experiment 1) or told they had a 10% chance of winning $10 and given the opportunity to donate from their potential winnings (Experiments 2–4). Across the four experiments, participants in all of the narrative conditions and in some of the argument conditions tended to express more positive attitudes toward charitable giving and donated about $1 more on average than did participants in the control conditions. These effects appear to have been mediated by the “narrative transportation” scale, which suggests that appeals to donate can be effective if they engage participants’ emotions, imagery, and interest.

The burgeoning science of ethics has produced a trend toward pessimism. Ordinary moral thought and action, we’re told, are profoundly influenced by arbitrary factors and ultimately driven by unreasoned feelings. This book counters the current orthodoxy on its own terms by carefully engaging with the empirical literature. The resulting view, optimistic rationalism, shows the pervasive role played by reason, and ultimately defuses sweeping debunking arguments in ethics. The science does suggest that moral knowledge and virtue don’t come easily. However, despite the heavy influence of automatic and unconscious processes that have been shaped by evolutionary pressures, we needn’t reject ordinary moral psychology as fundamentally flawed or in need of serious repair. Reason can be corrupted in ethics just as in other domains, but a special pessimism about morality in particular is unwarranted. Moral judgment and motivation are fundamentally rational enterprises not beholden to the passions.

How can we make moral progress on factory farming? Part of the answer lies in human moral psychology. Meat consumption remains high, despite increased awareness of its negative impact on animal welfare. Weakness of will is part of the explanation: acceptance of the ethical arguments doesn’t always motivate changes in dietary habits. However, we draw on scientific evidence to argue that many consumers aren’t fully convinced that they morally ought to reduce their meat consumption. We then identify two key psychological mechanisms—motivated reasoning and social proof—that lead people to resist the ethical reasons. Finally, we show how to harness these psychological mechanisms to encourage reductions in meat consumption. A central lesson for moral progress generally is that durable social change requires socially-embedded reasoning.