Philosophy in the 20th century conceived of itself as distinct from empirical disciplines. Kwame Anthony Appiah's project is to bring economics, psychology and philosophy back together; to reconstitute the moral sciences.
Many philosophers are sceptical about the relevance of empirical moral psychology to ethics. One shibboleth of modern philosophers is that "we cannot derive an ought from an is", so factual premises alone will never be enough to tell us what we ought to do.
But it is also widely accepted that "ought implies can", or that we cannot be obliged to do something if it is not possible for us to do it. This suggests that facts about human nature are relevant to ethical inquiry. There is an emerging strand of "experimental ethics" that takes psychological results very seriously and even sees some philosophers conducting experiments of their own. It opens up a host of questions about the proper relationship between philosophy and the social and natural sciences.
This book, which Appiah describes as "in the nature of a preliminary report from the laboratory of reflection", is based on a set of lectures in which his brief was to engage a non-specialist audience. His style is chatty and erudite, full of stories and literary references. These both entertain and distract, making it hard to pin down the argument.
Appiah begins by showing that, like other communities, modern philosophy constructs its history to support its conception of itself. He traces its genealogy to show that mental philosophy and psychology, moral philosophy and economics are not as distinct as some philosophers would have us think. He then goes on to present a plethora of recent research at the intersection of moral philosophy and psychology, and to offer some speculations of his own about the relationship between the two.
Themes that recur throughout the book are the relation between reasons and moral judgments, and the relation between how we evolved to be and what we ought to value. Appiah reports experiments that show that people's helping behaviour is often affected by things we would regard as morally irrelevant (such as finding a dime in a phone box, being in a hurry, being outside a fragrant bakery). He also cites studies that question the relation between our moral judgments and the reasons we offer for them. Some psychologists think that the main role of reasons is as a post-hoc justification of judgments based on intuition.
Appiah's response is to distinguish between the causal explanations found in the sciences and the reason explanations with which philosophers are concerned. He suggests that causal explanations belong to the Sinnenwelt, or world of being, and moral justifications to the Verstandenwelt, or world of reasons. All very well, but if reasons do not play a role in our best explanation of behaviour, then why should we be interested in them? Appiah's answer is that we need the Verstandenwelt because the Sinnenwelt is not intelligible to us as ordinary persons. This is unsatisfying. Scientists do understand the world in terms of causes, and so can ordinary people when it is explained to them in those terms. It also ducks the difficult issue of the relation between reasons and causes.
When it comes to ethical decision-making, Appiah suggests that people are guided by "moral heuristics". This is supposed to parallel the idea from cognitive psychology that people use simple rules, which get results that approximate those of a time- and resource-consuming optimising calculation. We developed such heuristics because creatures that had a fast, frugal rule for working out how to get fitness-maximising resources did better in the evolutionary stakes (even if they sometimes went wrong).
In order to think that we are hard-wired to short cut complicated ethical decisions in this way, you would have to think that the morally correct action is the same as the fitness-maximising one. In fact, ethical behaviour often involves making fitness sacrifices and there is a vast literature on why it would have evolved nonetheless. Appiah does not explain why any heuristic in the moral domain would lead to the morally correct, as opposed to the fitness-maximising, decision.
At other points in the book, Appiah implies that his account contributes to our understanding of how our moral sentiments evolved. In this case, one might wonder what the relation is between what we evolved to value and what we ought to value. Appiah's main conclusion seems to be that the values we evolved to have are the building blocks of ethical theorising. This is hardly a startling conclusion; certainly not one that merits taking some 288 pages to reach.
Empirical discoveries are relevant to ethics, and there are many interesting questions about the relation between experiments and moral enquiry. But Appiah's book doesn't bring us any closer to answering them.
Experiments in Ethics
By Kwame Anthony Appiah
Harvard University Press
Published 28 February 2008