Several readers have asked me to comment on a recent talk given by Sam Harris entitled “Science can answer moral questions.”
Physicist Sean Carroll rebuffed Harris, saying:
There is a old saying, going back to David Hume, that you can’t derive ought from is. And Hume was right! You can’t derive ought from is. Yet people insist on trying.
Harris replied here, though his full argument will arrive later this year in The Moral Landscape: How Science Can Determine Human Values.
What can we make of this debate? Let me offer a few brief thoughts.
First, Hume never said you can’t derive an ought statement from an is statement.1 What he did say is that nobody up to his day had explained how to derive an ought from an is. And it does seem like a difficult problem. It isn’t obvious that “Rape is a cause of suffering” necessarily implies “Therefore, we ought not rape.” These appear to be two fundamentally different kinds of claims. But the mere appearance of a gap between ought and is does not prove anything.
John Searle gave a famous counter-example to the apparent is-ought gap:2
- Jones said, “I promise to give you, Smith, five dollars.”
- Jones promised to give Smith five dollars.
- Jones undertook an obligation to give Smith five dollars.
- Jones is under an obligation to give Smith five dollars.
- Jones ought to pay Smith five dollars.
Now it looks like we have logically and uncontroversially derived an ought from an is.
My point is only that Hume did not end the discussion on ought and is. This is a hotly debated topic. In fact, if I had to guess, I would guess that most philosophers today think you can derive an ought from an is.3
But Carroll does not believe in objective morality:
There are not objective moral truths (where “objective” means “existing independently of human invention”), but there are real human beings with complex sets of preferences. What we call “morality” is an outgrowth of the interplay of those preferences with the world around us, and in particular with other human beings. The project of moral philosophy is to make sense of our preferences, to try to make them logically consistent, to reconcile them with the preferences of others and the realities of our environments, and to discover how to fulfill them most efficiently.
If I had read that last sentence in isolation, I might have thought Carroll was endorsing the theory of objective moral realism I defend: desirism. And anyway, the facts about which sets of preferences are logically consistent, and the facts about which sets of preferences reconcile most efficiently with the preferences of others and the realities of our environments – aren’t these “moral” truths that exist “independently of human invention”? It would seem so.
But the central question here is how we define moral terms, as Harris recognizes:
[Many] people strongly objected to my claim that values (and hence morality) relate to facts about the wellbeing of conscious creatures. My critics seem to think that [while] maximizing the wellbeing of conscious creatures may be what I value, other people are perfectly free to define their values differently, and there will be no rational or scientific basis to argue with them. Thus, by starting my talk with the assertion that values depend upon actual or potential changes in consciousness, and that some changes are better than others, I merely assumed what I set out to prove. This is what philosophers call “begging the question.”
I believe that we can know, through reason alone, that consciousness is the only intelligible domain of value. What’s the alternative? 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.
Harris is expressing a popular philosophical view that value supervenes on brain states. To say that something has value and yet is not valued by any being is just a confusion, Harris thinks.
So Harris’ central claim is that terms about moral value refer to brain states. And since science can tell us a great deal about brain states, and about how actions and desires and policies affect brain states, therefore science can tell us which actions and desires and policies are morally right and wrong.
Carroll’s reply is that science cannot show us that terms about moral value refer to brain states. Science cannot tell us that ought is derived from facts about brains states. Why not say that moral value is grounded in intrinsic value, or rights and duties, or God’s commands?
What are the data we can point to in order to adjudicate this disagreement? …How are we to balance individual rights against the collective good? You can do all the experiments you like and never find an answer to that question… When [people] don’t share values, there’s no way to show that one of the parties is “objectively wrong.”
Unfortunately, Harris clouds the issue with some emotional bludgeoning, as if he were William Lane Craig giving the moral argument for God’s existence:
There are women and girls getting their faces burned off with acid at this moment for daring to learn to read, or for not consenting to marry men they have never met, or even for the crime of getting raped. Look into their eyes, and tell me that what has been done to them is the product of an alternative moral code every bit as authentic and philosophically justifiable as your own.
But of course Carroll hates these cruelties. And of course it’s not that he thinks all moral codes are equal, he just doesn’t think any of them are objectively true.
I will not try to argue who is right or wrong in this debate. Rather, I will try to clarify the debate by drawing attention to the questions that matter.
First, how do we define moral terms? Is Harris justified in saying that moral terms are most reasonably defined in reference to brain states, or is it just as justified to define moral terms in other common ways, for example in reference to universal maxims or hypothetical social contracts? How can we go about answering such a question? Will a dictionary settle the matter, or is it more complicated than that?
Second, if Harris can reasonably define moral terms in reference to brain states, is his more specific definition of moral terms in reference to the wellbeing of conscious beings justified? Why “wellbeing”? Why only conscious beings?
If these two sets of questions are granted in Harris’ favor, then Harris and Carroll will agree that science has much to say about which actions, desires, and policies promote the wellbeing of conscious beings. That is not disputed.
Of course, Carroll is right that science cannot tell us what the “correct” definition of morality is. Even Harris seems to concede this is the domain of “reason alone.”6
But this might be a trivial concession for Harris to make. After all, science cannot say anything about protons until we have settled on the definition of “proton.” It does not diminish the scientific nature of proton-study to point out that science itself cannot determine the correct definition of the word “proton.” Likewise, perhaps the scientific nature of morality is not diminished by the fact that science itself cannot determine the correct definition for “morally good.”
- Read Hume’s famous paragraph at the top of this Wikipedia article. [↩]
- Searle, “How to Derive ‘Ought’ from ‘Is’” in The Philosophical Review (1964). [↩]
- Why do I guess this? because most philosophers are moral realists, and moral realism depends on the claim that there are facts of the is type with ground ought claims, for example “Murder is wrong” grounds the claim “One ought not murder.” Or, more substantively, a moral realist might say that “Murder does not promote the greatest happiness for the greatest number” grounds the claim “One ought not murder.” [↩]
- Harris writes of “Hume’s lazy analysis of facts and values.” Certainly, he may disagree with Hume’s analysis, but lazy? Hume’s work is widely regarded as the clearest thinking on morality up to his day, and sets the framework for thousands of pages of dense ethical philosophy published in peer-reviewed journals each year. Hume may be wrong, but he was not lazy in thinking about morality. [↩]
- Harris writes as if Carroll has said that moral disagreement proves the subjectivity of morality, or as if Carroll equates scientific consensus with scientific truth; but Carrol does neither. [↩]
- I refer to Harris’ statement: “I believe that we can know, through reason alone, that consciousness is the only intelligible domain of value.” [↩]