In a famous passage of his 1738 Treatise of Human Nature, philosopher David Hume discussed an important distinction.

Hume observed of other books on ethics that “the author proceeds for some time in the ordinary way of reasoning and establishes the being of a God, or makes observations concerning human affairs” when a subtle but crucial shift occurs in their writing. These ethics authors move from speaking of “is, and is not” to speaking of “ought, or an ought not.” That is, they infer from facts about the world (what “is and is not”) that there is a right and wrong, or good or bad (what “ought or ought not” be).

Hume cannot see a way that a given set of facts can ever entail what is the right thing to do. He suggests that it “seems altogether inconceivable, how this new relation [what you ought do], can be a deduction from others [what is and is not], which are entirely different from it.” There is a gap, Hume suggests, between normative conclusions — conclusions about what we should do, or what it would be right to do, or about whether certain states of affairs are good or just or otherwise valuable — and purely factual premises.

Subsequent philosophers have called this insight “the fact/value distinction” or “the is/ought gap.” Conflating these is sometimes called the “naturalistic fallacy.” The idea that the logical leap from “is” premises to “ought” conclusions is illegitimate has shaped the last few hundred years of philosophical discussion about morality.

In the last several years, however, the neuroscientist, political commentator, and podcaster Sam Harris has repeatedly argued that Hume was wrong. He suggests that you can, in fact, infer an “ought” from an “is.”

Harris promises the possibility of being able to conclude from facts about the world that there is indeed a right and wrong, a good and bad. Ultimately, though, it’s a promise he can’t keep.

I. The Argument from the Stove

In a series of tweets from 2018, Harris makes light of the very idea of fact/value distinction.

It’s not clear what conclusion Harris is trying to establish. His claim in tweets 4 and 8 that we can use our knowledge of the facts to figure out how to implement our values is one that no one — not Hume and not anyone else in the history of philosophy — would deny.

For example, here is Immanuel Kant channeling Hume in his Groundwork of the Metaphysics of Morals:

The practical part of a science is concerned only with what must be done to achieve a certain purpose; it doesn’t address the question of whether the purpose is reasonable and good. The instructions to a physician for how to make a patient thoroughly healthy, and for a poisoner to bring certain death to his victim, are of equal [practical] value in that each serves perfectly to achieve its intended purpose.

To see the distinction Kant is making here, imagine that you’re a doctor and you’ve been asked to treat a mass-murdering dictator. If you think you have a moral obligation to save him, your knowledge of medical science can tell you how to do so. If you have a moral obligation to poison him in the hopes that someone less brutal succeeds him, the same body of factual information can help you figure out how to do that.

Hume and Kant understand perfectly well that empirical facts can tell us how to achieve our moral goals. Even though the two thinkers had profoundly different views about what morality is, they both stressed that those facts can’t tell us whether the doctor should treat the dictator or poison him instead.

II. The Hot Stove and The Worst Possible Misery

Let’s charitably assume Harris understands that his claim that facts can tell us important things about how to act on our values is philosophically uncontroversial.

In that case, another possible interpretation is that he acknowledges there is a logical gap between factual premises and normative conclusions but he doesn’t think it matters very much.

On this reading, Harris’ idea is that once we’ve figured out the facts, the way they combine with values to give us the right normative conclusions is just too trivially obvious to be worth spelling out. Anyone who thinks that morality itself is complicated enough that we need to consult not only science but moral philosophy to figure out the right thing to do is simply letting herself get lost in esoteric abstractions. Touch the hot stove again and common sense will re-assert itself. Pain sucks.

One problem with (this interpretation of) Harris’ argument is that he seems to be conflating finding something unpleasant (it “sucks”) with concluding that it’s objectively morally bad.

To start to see the problem here, consider the fact that many high-income people think that forking over a significant part of their wealth in taxes “sucks.” On the other hand, poor people tend to think that living in poverty sucks and that social welfare programs that alleviate their financial stress make it suck a bit less. How do we do we morally adjudicate whose claim ‘wins’?

To see how Harris would answer this question, let’s turn to his 2010 book The Moral Landscape, in which he talks about “the well-being of conscious creatures” as the goal of morality. He also says that “a universal morality can be defined with reference to the negative end of the spectrum of conscious experience.”

[Imagine] a state of the universe in which everyone suffers as much as he or she (or it) possibly can. If you think we cannot say that this would be bad, then I don’t know what you mean by the word “bad” (and I don’t think you know what you mean by it either).

He then contrasts this “worst possible suffering” or “absolute misery” with the contrary state of “absolute bliss” and then concludes that we can evaluate the morality of any given course of action by seeing which direction it moves along on the “moral landscape” defined by these two poles. Any talk of one state being morally “better” than another must refer to “positive changes in the experience of sentient creatures.”

I’ll have more to say about this argument below. For now, the important takeaway is that Harris’ answer to how to adjudicate between competing claims about what sucks is to see, for example, how much redistribution sucks for the wealthy and compare this to the amount of “well-being” or “bliss” it generates for its beneficiaries. This is a view called consequentialism — the moral theory advocated by John Stuart Mill, Jeremy Bentham, and Peter Singer among others.

Many of Harris’ most controversial political views — from his endorsement of torturing terrorism suspects in “ticking time bomb” cases to his infamous musing about how a nuclear first strike might be “necessary” under certain circumstances — would seem to indicate that he holds to a fairly straightforward version of consequentialism.

It’s important to note, though, that consequentialism is hardly the only possible answer to the question about how to adjudicate competing moral claims. There are several different moral theories.

For example, hard-core libertarians like Robert Nozick (at least in the stage of his career when he wrote his most famous book) might argue that capitalist property rights are more morally important than alleviating suffering. John Rawls, on the other hand, would argue that we should pursue the policy that will benefit the worst off whether or not it leads to the overall best consequences when we add up all the well-being and subtract all the pain.

Using our charitable interpretation of Harris’ hot stove example, his point is that it’s just obvious — just a matter of simple everyday common sense — that the consequentialist answer to these questions is the right one. But why should we assume that?

III. Consequentialism and the Trolley Case

Consider a classic moral example first put forward by Philippa Foot:

Edward is the driver of a trolley whose breaks have just failed. On the track ahead of him are five people; the banks are so steep that they are not able to get off the track in time. The track has a spur leading off to the right, and Edward can turn the trolley onto it. Unfortunately, there is one person on the right-hand track. Edward can turn the trolley, killing the one; or he can refrain from turning the trolley, killing the five.

Students who are reading that passage for the first time often think that a complete and adequate explanation of why Edward should turn the trolley is “fewer people will die that way.” Hume’s point, however, is that the conclusion doesn’t logically follow from this premise by itself. To get to the conclusion that Edward should turn the trolley, we need both Premise 1 and Premise 2 below.

Premise 1: The consequences of Edward turning the trolley will be better than the consequences of his failing to turn it.

Premise 2: The morally best course of action is always the one with the best consequences.

Conclusion: The morally best course of action would be for Edward to turn the trolley.

So far, this might seem like an interesting technical quibble, the logical equivalent of correcting an error in grammar or spelling. This might be Harris’ point about the Hot Stove and the Worst Possible Misery — that it’s just obvious that Premise 2 is correct.

Hold that thought while we consider a variation of Foot’s example suggested by Judith Jarvis Thomson:

George is on a footbridge over the trolley tracks. He knows trolleys and he can see that the one approaching the bridge is out of control. On the track back of the bridge there are five people; the banks are so steep that they will not be able to get off the track in time. George knows that the only way to stop an out-of-control trolley is to drop a very heavy weight into its path. But the only available, sufficiently heavy weight is a fat man, also watching the trolley from the footbridge. George can shove the fat man onto the track in the path of the trolley, or he can refrain from doing this, letting the five die.

If the argument given above is a good one, then this one should be just as good:

Premise 1: The consequences of George pushing the man will be better than the consequences of his failing to push him.

Premise 2: The morally best course of action is always the one with the best consequences.

Conclusion: The morally best course of action would be for George to push the man.

Over the course of the decade or so that I’ve been teaching introductory philosophy and ethics classes, all my classes’ immediate “common sense” reaction to this second version of the Trolley Case was that it would be “obviously” wrong for George to push the man.

Consequentialism, it seems, isn’t always the obvious answer.

Of course, consequentialist moral philosophers have come up with sophisticated ways around this and related problems. (Non-consequentialists have in turn come up with similarly sophisticated responses to these arguments. And, as Salvoj Žižek would say, so on and so on and so on.)

Even if some elaborate defense of consequentialism is right, however, this wouldn’t validate Harris’ apparent belief that the truth of consequentialism is just obvious.

IV. Evaluating the Worst Possible Misery Argument

If Harris isn’t just asserting the uncontroversial and uninteresting claim that empirical premises can do some work in helping to establish moral conclusions, and he isn’t making the far more dubious claim that consequentialism is so obviously correct that the only real ambiguities about morality arise from our lack of knowledge of relevant empirical facts, what is Harris doing?

It could be that he doesn’t think consequentialism is such an obvious consequence of common sense that you need only to touch a hot stove to realize that it’s true. Maybe instead he thinks the Worst Possible Misery Argument is enough to establish it.

On this reading, the Hot Stove Argument is simply a compressed (and thus less clear) version of the same line of reasoning. There are at least four problems with this interpretation of Harris’ point.

First, very different moral theories could explain in very different ways why the Worst Possible Misery scenario would be bad.

For example, thinkers who agree with Aristotle that justice is a state in which everyone gets what they deserve might think also that the Worst Possible Misery is really bad. The question, though, is why the Worst Possible Misery is bad. Aristotelians might say it’s bad not simply because suffering is bad per se, but because if every sentient creature is maximally suffering (and not just the ones that deserve to suffer that much), most of us are getting something worse than what we deserve.

Second, even if consideration of the Worst Possible Misery and the Hot Stove does convince us of the (extremely plausible) premise that suffering is bad, it wouldn’t follow that happiness is good. For a short and funny explanation of where the premise that the only thing that’s good is avoiding pain gets you, see Ryan Lake’s comic about negative utilitarianism.

Third, even if we also accept the (extremely plausible) premise that happiness is good and suffering is bad, it wouldn’t follow that only happiness is good and only suffering is bad. That logical leap is no different from inferring from the premise that elephants are large that all large creatures all elephants.

It could be that seeking happiness and avoiding pain are only two of several important values, and that there are complicated philosophical problems of how to weigh competing values against each other. This would, in fact, be a pretty plausible lesson to take from classic objections to utilitarianism like the one derived from Thomson’s version of the Trolley Case.

Fourth and most importantly, even if any of what Harris says did add up to a good argument for consequentialism, it would have absolutely nothing to do with the gap between “is” and “ought.” The key move, after all, is an appeal to intuition about what we ought to avoid, not any sort of direct inference from scientific facts.

V. The Health Argument

Harris has one more argument worth considering. In The Moral Landscape, he appeals to an analogy between morality and physical health. The latter, he argues, is surely an empirical matter — even though it seems vulnerable to some of the same worries I’ve been raising in this article.

I wonder if anyone on earth who would be tempted to attack the philosophical underpinnings of medicine with questions like: ‘What about all the people who don’t share your goal of avoiding disease and early death? Who is to say that living a long life free of pain and debilitating illness is ‘healthy’? What makes you think that you could convince a person suffering from fatal gangrene that they were not as healthy as you are?’ And yet these are precisely the kinds of questions I face when I speak of morality in terms of human and animal well-being.

At first glance, this looks like a much better argument than either of the other two we’ve considered so far. There is a pretty clear-cut similarity between the conceptual questions you could raise about health and the ones you could raise about morality.

But Harris doesn’t linger on the analogy long enough to see where it leads. You could ask similarly silly questions about ethics — “Who is to say that torturing small children for fun is wrong?” — but as we’ve seen, you can also ask much more interesting and controversial ones like, “Given situations where you could either actively kill one innocent or let five innocents die, what’s the right thing to do?” These questions are the ones we have to use moral philosophy to navigate, since the answers aren’t obvious and science simply isn’t relevant.

Similarly, replace “fatal gangrene” with “gender dysphoria” in Harris’ last hypothetical question and you have a far more controversial case. Not so long ago, the question of whether same-sex attraction should be classified as a mental disorder was similarly controversial. Homosexuality was removed from the Diagnostic and Statistical Manual of Mental Disorders (DSM) not primarily because of new scientific information about the causes of same-sex attraction coming to light — in fact, science hasn’t progressed very far on that front — but because this was one of many successive battles won by the gay liberation movement on the normative front.

Finally, consider the recent dust-up about the American Psychological Association’s guidelines about toxic masculinity. The argument, in all three cases, is about the dimension of what we collectively consider to be the good life that’s relevant to the attentions of medical professionals.

Harris’ confusions stem from his conflation of medicine with the philosophy of health. The former is, as Kant explains in the passage from The Groundwork of the Metaphysics of Morals quoted above, the applied science that deals in factual information about how to achieve our health goals. The latter concerns controversies about those goals. Debates about standards of health haven’t historically occupied the minds of philosophers as have debates about standards of morality for the simple reason that disagreements about health tend to be less common and more tractable than disagreements about morality, but the issues are conceptually similar. Medicine is to the philosophy of health as economics and sociology are to moral controversies about economic inequality and the ethics of redistribution.

VI. Conclusion

Harris is in many ways impressive. He’s a talented writer with a Ph.D. in Neuroscience and a massive following. If he’d delved into the academic literature on these issues before writing about them, he might have had interesting things to say and contributed to the general public’s understanding of philosophy in the process.

Unfortunately for all of us, that’s not what he did.

Ben Burgis is a philosophy professor at Georgia State University Perimeter College and is the author of Give Them An Argument: Logic for the Left. He does a regular weekly segment on The Michael Brooks Show called The Debunk. His writings have appeared in Jacobin, Quillette, Areo, and elsewhere. Follow him on Twitter @BenBurgis.