Braintrust: What Neuroscience Tells Us about Morality (review)

"I began this project," writes Patricia Churchland, "because I wanted to understand what it is about the brains of social mammals that enables their sociability, and thus to understand what grounds morality" (10). Appeal to neither supernatural revelation nor to some rarefied notion of reason, she insists, can provide a reasonable account of human moral behaviour (6). She acknowledges that, speaking formally, ought cannot be derived from is but argues that when derived is understood more broadly as infer, it is clear that reasonable decisions regarding moral practices are possible. Such reasoning proceeds by way of constraint satisfaction that involves weighing factors and probabilities relevant to answering moral questions (7). In ethics, argues Churchland, there are no uniquely right choices—only better or worse choices "balancing and harmonizing and settling on . . . suitable decision[s]" (25). Indeed, for Churchland, solutions to social problems can be "better than others as a matter of fact" and, "relative to these values, practical policy decisions can be negotiated" (9). Thus, she argues in some depth in chapter 7 that rules and their rational application are not definitive of morality (166) and that morality is more a matter of social skill. As she puts it, "The ability to appreciate when a circumstance is a fair exception, or which rule to follow when rules conflict, embodies some of the most refined aspects of social understanding" (167). I shall return to this issue below. For Churchland, social desires such as "the attachment to family members, care for friends, and the need to belong" (12) are at the root of human moral practices, and these values, she maintains, involve a particular kind of brain circuitry. The fundamental question for Churchland, then, is how brains came to care about others, for in terms of evolutionary theory, caring for the self—protecting the self against external dangers (including other persons, especially the stranger)—is a ground floor function of the human nervous system (30). These fears appear at the most elemental level of existence and are coordinated by subcortical structures such as the brain stem, amygdala, and hypothalamus that respond to potential threats posed by other organisms by producing such defensive behaviours as prudence, vigilance, caution, and the "freeze-flight-or-fight" response. Despite these elemental behaviours, however, social emotions and behaviours, Churchland points out, "are not the result of a wholly new engineering plan." (46). Social behaviours and values, she points out, come by way of modification of the self-preservation mechanisms. The first step to the emotion of "other-caring" is an extension of the self-caring instinct to helpless offspring. That extension is made possible by the "maternalization" of the brain that in turn depends upon the effect of neuro-peptides such as oxytocin and arginine vasopressin (as well as several hormones), which inhibit the defensive behaviours essential to self-preservation produced by the amygdala. This brain modification is slight, but it yields significant new social behaviours at the macro level, first, for example, in relation to positive encounters with the helpless infant. The "downregulation" of the autonomic fight or avoidance responses with respect to the infant, Churchland argues plausibly, also makes possible other social interactions at the macro level by raising the threshold for the tolerance of others. And this generates forms of behaviour that, Churchland maintains, eventually flower into morality. As she puts it, "Our brains are structured to see to our own interests, but also to those of kin and kith" (59). And moral behaviour, she suggests, can be seen to be part of the same spectrum of actions. The cooperative behaviour seen in kin relations, that is, indicates the possibility that cooperative interactions can regularly occur between unrelated friends and with strangers (62).

Unlike Mark Hauser (and others) who seem to believe in the existence of a "moral organ" that produces moral thought and behaviour, Churchland maintains that there is no need for invoking such devices for truth-telling or social cooperation. These behaviours, for her, "can be explained...