Influential scientist and author Sam Harris has lately taken up the subject of the application of neuroscience to morality. His claim: that “there are right and wrong answers to moral questions, just as there are right and wrong answers to questions of physics, and such answers may one day fall within reach of the maturing sciences of the mind.” Much of what Harris says is right. For example, most, though not all, philosophers would agree with his rejection of moral relativism, especially the mushy-headed examples of relativism that he cites. I think he is also right to see relevance for brain science to questions of human happiness. But with all due respect to Mr. Harris, I will focus here on what I think he gets wrong.
One mistake is his ad hominem dismissal of the naturalistic fallacy. This is captured in the claim that it is impossible to derive a normative statement from purely factual premises— simply put, you can’t get an ‘ought’ from an ‘is.’ As Harris notes, this view originates in Hume’s Treatise of Human Nature, the argument of which Harris describes as "lazy" and not the "last word on the subject of morality until the end of time."
But while it is true that there is some debate about how to understand the naturalistic fallacy and even whether it is really a fallacy, Hume is hardly the only one to have seen a problem in deriving statements of moral obligation from statements of fact. Intuitively, it is hard to see how we can know anything about how the world ought to be purely from knowledge of how it is. More specifically, study of the mind can show us only what people desire, or what makes them happy. It cannot show us that we ought to strive to help them fulfill their desires, or value their happiness.
[By the way, Hume’s treatment of the basis of moral judgment does not deserve to be so glibly rejected. Hume at his laziest is better than Harris at his best, and more rewarding of careful study, too. But I digress.]
Harris runs together a number of distinct claims. He seems to think that the ‘no-ought-from-is’ claim entails the claim that all ought claims are subjective in the sense of being neither true nor false. It does not. Kant, for example, agrees with the first claim but not the second. Harris furthermore seems to assume without stating that the methods of natural science are the appropriate methods for resolving all questions of fact, and this too is debatable, to put it mildly. One can be a cognitivist in moral theory (this is the view that there are knowable moral facts) without thinking that moral facts can be observed in a laboratory. Harris’ view might be both coherent and true, but this requires more and better argument than he gives.
The second major mistake Harris makes is his too-hasty embrace of the idea that moral statements can be analyzed exhaustively into statements about human conscious states, specifically statements about human well-being. Curiously, he does not argue for the identification of well-being with conscious states. It seems entirely possible to me that my well-being might be increased by something of which I am not aware. Nor am I clear on his reasons for thinking that only conscious states can be of value. The act of valuing might be said to be a conscious state (though I can think of counterarguments to that, too), but it doesn’t follow from that that conscious states themselves are what is valued. One can (I would say should) value the health of the planet, and my valuing might be reducible to a conscious state of mine, but the thing valued is not at all describable as a conscious state.
But even if we give Harris a pass on these points, there is still the bigger issue of the relation between moral obligation and human well-being or happiness. On this at least Harris does offer an argument of sorts. Here it is:
Imagine some genius comes forward and says, "I have found a source of value/morality that has absolutely nothing to do with the (actual or potential) experience of conscious beings." Take a moment to think about what this claim actually means. Here's the problem: whatever this person has found cannot, by definition, be of interest to anyone (in this life or in any other). Put this thing in a box, and what you have in that box is -- again, by definition -- the least interesting thing in the universe.
Well… OK. This establishes at most that we cannot be interested in something of which we cannot be conscious—a claim that I’ve never heard disputed. But if we are to take this as showing that moral claims have only to do with human well-being, let alone conscious well-being, then clearly Harris is making the mistake I just described, confusing the act of valuing with the thing being valued. (For a vastly better, though still problematic argument for roughly the same point, see Chap. III of John Stuart Mill’s Utilitarianism.)
The issue Harris claims to have solved at a stroke is one that goes back to Plato: On the one hand, in order to have motivation to act morally, our moral beliefs must speak to some desire in us; on the other hand, if that is all that they speak to, then our moral theory risks becoming mere egotism. Socrates argues at length in the Republic that justice is a “benefit.” The moral philosophers of the early modern era wrestled with how to ground an account of moral action in human nature while nevertheless providing a robust account of moral obligation. Perhaps Harris has found something that all these earlier philosophers have missed—but I doubt it.
[Mr. Harris will apparently be coming out with a book soon, under the title The Moral Landscape: How Science Can Determine Human Values. The material discussed in this post, however, is taken from a longish piece in the Huffington Post, linked above.]