Evolution, we are told, can explain why we have moral sentiments, and indeed theoretically it can explain why we have the sense that some things are right and other things are wrong, but evolution cannot impress upon us a duty to do the things we believe are right. A blind, impersonal process cannot impose obligations. One who transgresses whatever moral sentiments may have evolved in our species needs something more than the fact that his behavior doesn't accord well with the mutations which have accrued in the human genome to convince him that he's doing something truly wrong.
Another problem with trying to ground morality in evolution is that if compassion and generosity are the products of natural selection then so, too, must be avarice and violence. How then, if our evolution is our guide to morality, do we say that the former are good and the latter bad? By what principle do we choose between these behaviors and where did that principle come from?
Another possibility is that given that happiness is good, science can tell us how we can best achieve it, but this, too, is fraught with difficulties. Just because I recognize that happiness is good doesn't mean that I have a duty to nurture it in anyone but myself. In other words, my happiness is good, but why should I consider your happiness to be good, or the happiness of people I don't even know?
James Davison Hunter and Paul Nedelisky consider the question whether science can provide an adequate foundation of morality in a paper at The Hedgehog Review. The authors examine a number of attempts to provide a scientific underpinning for morality and conclude that the actual science in these attempts is nothing more than philosophical window dressing. After dispensing with several failed attempts to provide a foundation for morality rooted in empirical data they turn to the recent work of philosopher Sam Harris who writes this:
Science cannot tell us why, scientifically, we should value health. But once we admit that health is the proper concern of medicine, we can then study and promote it through science....I think our concern for well-being is even less in need for justification than our concern for health is....And once we begin thinking seriously about human well-being, we will find that science can resolve specific questions about morality and human values.Harris makes two assumptions here that Hunter and Nedelisky think fatal to his argument that science can ground morality:
[F]irst, that well-being is a moral good, and, second, that we know what the observable properties of well-being are. Yet [Harris] doesn’t see these assumptions as problematic for the scientific status of his argument. After all, he reasons, we make similar assumptions in medicine, but we can all recognize that it is still a science. But he still doesn’t recognize that this thinking is fatal to his claim that science can determine moral values. To make the problem for Harris more vivid, compare his argument above with arguments that share the same logic and structure:Additionally, Harris makes an error I alluded to above. It's not so much that he assumes well-being to be a moral good, although as Davison and Nedelisky point out, that assumption is problematic, rather it's his assumption that anyone has a duty, an obligation, to promote other people's well-being. That assumption is completely ungrounded. Why, for example, would it be wrong to state that my only moral duty, if I have any, is to myself and that others should see to their own interests?
Although these parallel arguments are outlandish to our ears today, they all, in fact, have historical precedent—and from not so long ago. Most tellingly, these arguments rely on the same logic as Harris’s. But of course they have little hope of showing that we should approve slavery, prohibit gay marriage, and bring about the elimination of Jews, gypsies, and the mentally disabled. Why? Because these arguments merely assume that we should, then recommend the scientific study and promotion of these ends.
- Science cannot tell us why, scientifically, we should value the enslavement of Africans. But once we admit that slavery is the proper concern of social science, we can then study and promote it through science. I think our concern for embracing slavery is even less in need for justification than our concern for health is. And once we begin thinking seriously about slavery, we will find that science can resolve specific questions about morality and human values.
- Science cannot tell us why, scientifically, we should value the purging of Jews, gypsies, and the mentally disabled from society. But once we admit that their eradication is the proper concern of social science, we can then study and promote it through science.
- Science cannot tell us why, scientifically, we should value a prohibition on gay marriage. But once we admit that such a prohibition is the proper concern of social science, we can then study and promote it through science.
Someone may reply that if I were to adopt that posture others will resent me, and I will suffer for it, but that's a purely prudential, not a moral, argument. The reply to it is that to which Plato adverts in The Republic: The best course of action is to act selfishly while deceiving others into thinking that you're actually unselfish. Indeed, the wisest course, given naturalism, is to be selfish while encouraging others to be altruistic. Why, on naturalism, would such a strategy be morally wrong?
The problem with attempts such as the Hedgehog article illuminates is that they are efforts to ground morality in human reason, but this is a quixotic task. Canadian philosopher Kai Nielsen made the attempt himself and toward the end of his career he finally acknowledged the futility of the endeavor. He wrote:
We have not been able to show that reason requires the moral point of view, or that all really rational persons, unhoodwinked by myth or ideology, need not be individual egoists or amoralists....Reason doesn't decide here....The picture I have painted is not a pleasant one. Reflection on it depresses me....Pure reason will not take you to morality.Nor will reason's handmaiden, science. Only a transcendent, personal moral authority which possesses the power to impose accountability can be an adequate ground for moral obligation.