Not that there's anything wrong in general with passion and intuition. Many of the most satisfying things in life (art, love, sex, food, etc.) would be impossible to enjoy dispassionately. But because the moral beliefs we espouse have grave consequences for both other people and ourselves, morality should not ultimately be just a matter of impulsive intuition, aesthetic judgment or personal taste. Moral rules are, after all, efforts to control the behavior of others (as well as ourselves), and in any culture that values personal freedom, this kind of imposition shouldn't be taken lightly. Cross-culturally, moral beliefs determine who is celebrated, who is ostracized, who is worshipped as a hero and who is put to death. They govern how we think about ourselves--what shames us, what we take pride in--and how others judge us. And moral beliefs don't operate only at an individual level. Whether a society as a whole can provide for its citizens, and compete successfully against other groups, may come down to the content of its moral system.

So how can we become more rational moral thinkers? The problem mentioned above--that of putting passion before reason--is unfortunately not the only, or even the most formidable, obstacle we face. A more fundamental problem is that of deciding how to even define "rationality" in a moral context. To determine whether a moral rule is rational or not, we need to decide what the goal of that rule should be: Who is the rule supposed to benefit? Sam Harris addresses this question in The Moral Landscape: How Science Can Determine Human Values. He argues that the goal of a rational moral system should be to promote the general well-being of conscious creatures. The problem with this idea is that it overlooks a principal way in which people were designed, by evolution, to use moral rules.

To understand what Harris' approach is missing, consider the arguments made by Richard Alexander in The Biology of Moral Systems. Alexander notes that people strive for goals that would have promoted their individual genetic fitness (survival and reproduction) in ancestral environments, and that an important way in which they do so is by cooperating in groups of people with whom they share common interests. By cooperating in groups, individuals can achieve their goals better than they could by acting alone, so it's in the individual's interest to cooperate. (Cooperation also presents individuals with dilemmas like the "free rider problem", but we can leave these aside for now). While cooperating in groups, people use moral rules in order to influence the behavior of group members in ways that will promote group success. This, Alexander argues, is a primary evolved function of moral rule-making: it enables individuals to more effectively pursue the interests they share with others in their group. For example, if people are cooperatively building a dam to protect their village from a flood, they might use rules like "all adult villagers should work on the dam for a minimum of X hours per day", "those who contribute above this minimum should be honoured", and "those who contribute below this minimum should be shunned". (Note that the promotion of shared interests is not the only evolved function of moralizing. Another important function is to signal to other people--honestly or not--that you have an altruistic or otherwise upstanding disposition. But that's a topic for another post).

If people use moral rules to better pursue their group interests, then it starts to become clear why Harris' proposal--that rational morality ought to promote the well-being of conscious creatures--will not generally apply. People use morality to pursue their own coalitional interests, not the interests of people in general, let alone conscious life in general. From this perspective, people judge the rationality of a moral rule not by how much it benefits conscious beings, but by how much it benefits their interest group. Now sometimes, the interests of the group may overlap with those of conscious creatures in general. For example, building the dam mentioned above would not obviously harm any conscious entity, and it would benefit the villagers, so it would seem consistent with the goal of promoting the welfare of conscious life. Another example where group interests overlap with those of conscious beings in general would be a group's effort to eradicate a disease like smallpox. However, situations such as these--where everybody has an interest in the same goal, and nobody has an interest in a conflicting goal--do not pose moral dilemmas, because they don't involve conflicts of interest between competing human coalitions.

In situations that do involve coalitional conflict, moral dilemmas cannot be solved by applying the "welfare of conscious creatures" rule. A primary reason why people cooperate in groups is so that they can compete more effectively against external groups, and moral disputes tend to arise out of these coalitional conflicts. In these contexts, you can't resolve moral debates by identifying the solution that would benefit all conscious beings, not only because this will often be difficult if not impossible, but also because that's not the goal that either side in the conflict will actually be fighting for. Consider, for instance, a conflict between loggers and hikers about whether the loggers should be allowed to cut down trees in a particular forest. The hikers might argue that this deforestation is morally wrong because it would deprive families of opportunities to enjoy nature, whereas the loggers might argue that it is morally good because it would create jobs for the support of families. Even if identifying the solution most beneficial to conscious life were possible in this situation, it wouldn't be the goal that either coalition would really be seeking. The loggers would be seeking the solution that most benefited loggers, and the hikers would be seeking the solution that most benefited hikers.