In The New York Time Book Review, Richard Rorty reviews Marc D. Hauser’s Moral Minds:How Nature Designed Our Universal Sense of Right and Wrong.
We need, Hauser says, a “radical rethinking of our ideas on morality, which is based on the analogy to language.” But the analogy seems fragile. Chomsky has argued, powerfully if not conclusively, that simple trial-and-error imitation of adult speakers cannot explain the speed and confidence with which children learn to talk: some special, dedicated mechanism must be at work. But is a parallel argument available to Hauser? For one thing, moral codes are not assimilated with any special rapidity. For another, the grammaticality of a sentence is rarely a matter of doubt or controversy, whereas moral dilemmas pull us in opposite directions and leave us uncertain. (Is it O.K. to kill a perfectly healthy but morally despicable person if her harvested organs would save the lives of five admirable people who need transplants? Ten people? Dozens?)
Hauser hopes that his book will convince us that “morality is grounded in our biology.” Once we have grasped this fact, he thinks, “inquiry into our moral nature will no longer be the proprietary province of the humanities and social sciences, but a shared journey with the natural sciences.” But by “grounded in” he does not mean that facts about what is right and wrong can be inferred from facts about neurons. The “grounding” relation in question is not like that between axioms and theorems. It is more like the relation between your computer’s hardware and the programs you run on it. If your hardware were of the wrong sort, or if it got damaged, you could not run some of those programs.
Knowing more details about how the diodes in your computer are laid out may, in some cases, help you decide what software to buy. But now imagine that we are debating the merits of a proposed change in what we tell our kids about right and wrong. The neurobiologists intervene, explaining that the novel moral code will not compute. We have, they tell us, run up against hard-wired limits: our neural layout permits us to formulate and commend the proposed change, but makes it impossible for us to adopt it. Surely our reaction to such an intervention would be, “You might be right, but let’s try adopting it and see what happens; maybe our brains are a bit more flexible than you think.”