Sam Harris has a contest on. “Anyone who believes that my case for a scientific understanding of morality is mistaken is invited to prove it in 1,000 words or less.” The best essay (as judged by Harris opponent and atheist philosopher Russell Blackford) will win $2,000 (and be published on Harris’s personal website). “You must refute the central argument of the book—not peripheral issues.” If any such essay actually changes Sam Harris’s mind, they will win not just $2,000 but $20,000 (and Harris will publicly recant his view).
Ophelia Benson has been critical of this contest (see A Losing Lottery Ticket, Sam Has to Presume a Great Big Ought, and a guest post from a commenter Why the Is/Ought Problem Matters). His own contest page (The Moral Landscape Challenge) has an important FAQ (a must read for any contenders). I actually am behind Harris’s program (I think his core thesis is correct, and I think Benson is wrong to say it is not), but I am not very impressed with Harris’s ability to defend or articulate it.
I had even greater problems with Michael Shermer’s attempt to defend the same core thesis Harris does, and I have commented before on how he was simply destroyed by his opponent, philosopher Massimo Pigliucci, even though I think Pigliucci is ultimately wrong and Shermer ultimately right (see Shermer vs. Pigliucci on Moral Science). I expect Harris will get similarly pwned. And that’s sad. Because it hurts their cause. They just aren’t the best defenders of this idea. And they should admit that and stop trying to be lone wolfs and look for and work with expert collaborators. There are several real, even renowned, philosophers who have been defending the same core thesis for years. Harris did not come up with anything fundamentally new here, and they have far more skill and experience dealing with the rigorous philosophical requirements of this debate.
Below I will explain what is wrong with Harris’s contest so far (and why it is not what Benson is concerned about); why what Benson has been saying is incorrect (and misses the point of Harris’ actual core thesis); and how (again) science can actually take over moral philosophy the same way it has done the theory of life (in the science of biology) and the universe (in the sciences of physics, astrophysics, and cosmology) and man and society (in the sciences of anthropology and sociology) and of mind (in psychology, neurophysiology, and cognitive science).
What Is the Point in Dispute Exactly?
Any contestant of course would need to know what exactly Harris means by a “scientific understanding of morality” that he wants people to try and refute. He gives this answer:
Morality and values depend on the existence of conscious minds—and specifically on the fact that such minds can experience various forms of well-being and suffering in this universe. Conscious minds and their states are natural phenomena, fully constrained by the laws of the universe (whatever these turn out to be in the end). Therefore, questions of morality and values must have right and wrong answers that fall within the purview of science (in principle, if not in practice). Consequently, some people and cultures will be right (to a greater or lesser degree), and some will be wrong, with respect to what they deem important in life.
This actually isn’t an adequate description of his thesis. Because this paragraph can mean a number of completely different things. One might reduce his argument to these propositions:
- Morals and values are physically dependent (without remainder) on the nature of any would-be moral agent (such that given the nature of an agent, a certain set of values will necessarily obtain, and those values will then entail a certain set of morals).
- By its own intrinsic nature, the most overriding value any conscious agent will have is for maximizing its own well-being and reducing its own suffering. This includes not just actual present well-being and suffering, but also the risk factors for them (an agent will have an overriding interest in reducing the risk of its suffering as well as its actual suffering; and likewise in increasing the probability of its long-term well-being as well as its present well-being).
- All of the above is constrained (and thus determined) by natural physical laws and objects (the furniture of the universe and how it behaves).
- The nature of an agent, the desires of conscious beings, and the laws of nature are all matters of fact subjectable to empirical scientific inquiry and discovery. (Whether this has been done or not; i.e. this is a claim to what science could do, not to what science has already done.)
- Therefore, there are scientifically objective (and empirically discernible) right and wrong answers in all questions of moral fact and value (i.e. what values people have, and what morals those values entail when placed in conjunction with the facts of the universe).
It might not be immediately obvious how the conclusion (item 5) follows necessarily from those premises (items 1-4), but it does. I think it should be evident to any observer of just this list of propositions, who thinks about it carefully enough. But I formally prove it (by deductive logical syllogism) in a chapter on this topic that was peer reviewed by four professors of philosophy: Richard Carrier, “Moral Facts Naturally Exist (and Science Could Find Them),” in The End of Christianity (ed. John Loftus; Prometheus Books 2011), pp. 333-64, 420-29. That should be required reading for anyone who wants to challenge this conclusion (for even more of my discussion of this thesis, in print and online, see the links provided in my article on Shermer vs. Pigliucci).
So the argument is logically valid (maybe not ever in any way Harris words it, but we should try to clean that up for him, lest we waste our time taking down his own straw man). That means we have to challenge the premises. But exactly what those premises assert is unclear in Harris’s hands (even as I have reworded them).
Confusion arises from Harris’s muddled wording (which is not much improved by my attempt to convert it into something more precise here; I approach the conclusion in a different way in my own work). What exactly does he mean by “values depend on the existence of conscious minds”? Depend in what sense? What does he mean by “well-being and suffering”? Those are crucial questions. Because his conclusion (as he states it) requires that “well-being and suffering” must always be any conscious agent’s most overriding goal, and it is not obvious why or how that can be (given the actual kinds of decisions humans engage in, which regularly sacrifice their own well-being for other goals) or what makes this “moral” as distinct from merely “prudential.” After all, isn’t pursuing solely your own individual well-being usually what we mean by immoral? Harris has done a terrible job of answering these questions.
I’ll show you a better way to look at and answer these questions in a moment. For now, let’s digress on the contest and Benson’s critique of it.
The Contest and the Benson Critique
All this confusion is largely Harris’s fault (I’ve tried, and given up, getting him to be more philosophically rigorous about what he is arguing, and I suspect he himself doesn’t quite know what he means or what the underlying logical structure of it is). Harris is a notoriously bad philosopher. And because he has such contempt for philosophy, he never learned to be any better at it (if you won’t even acknowledge that you can be, you obviously won’t take any self-educating steps to become so). So I have my own reservations about the utility of his contest. But they aren’t the reservations Benson has voiced.
Overall, I actually think this is a great idea, and wish more philosophers (and universities and foundations) would put prize money like this up to drive productive philosophical progress. Because real progress begins with well-judged crowdsourced debating just like this, to find the best case pro or con any x. Because progress is not possible until you have the best case to examine (and accept or refute) for any position. Academic peer review (for books and journals in philosophy) simply does not look for, nor even rewards, best cases. They just publish any rubbish that meets their minimal standards (and those standards are not very high, relatively to where they could be).
This doesn’t mean peer reviewed philosophy isn’t better than other philosophy. It generally is, at least in some respect worth the bother. But peer review standards in philosophy are also twisted and bizarre, excluding a lot of what actually is good philosophy simply because it doesn’t match some current fashion or irrelevant requirement. Whereas it is not as rigorous as it should be in policing fallacious, illogical, unscientific, or muddled argumentation. (And I am speaking as someone who has published academically peer reviewed papers in philosophy.)
(1) Contrary to Benson, I don’t think doing this is vain. It’s actually what the sciences and humanities often already do, a lot. Philosophy is actually behind the times in using approaches like this. And if I had the money, I’d do this every month, or quarter, on some question or other. In fact, I and a few others have been mulling the idea of creating an institute specifically to do that sort of thing. Of course, Benson was right to question just what the victory conditions were, since Harris (in his usual muddled and philosophically naive way) didn’t explain that. At all. Lots of people criticized him for it (not just Benson) and in reaction he eventually retooled the thing several times to be closer to a sensible way of doing it. Although it’s still, IMO, “batting the league minimum” as one might say. There are better ways to do this. But this at least is a start.
(2) Also contrary to Benson, I don’t think it’s relevant that “there are many people who [wrongly] persist in thinking [Harris's] book [The Moral Landscape] was a bold new theory of morality, that got everything right.” That is indeed silly. His book did not get everything right. Its core thesis is correct. But his book is not the best defense of it. And though his book contained some new ways of talking about it (most innovative being his analogy of there being several different “peaks of well-being” available on an overall “moral landscape,” after which his book is titled), he did not develop any “bold new theory of morality.”
Not only had I published an extensive defense of the same thesis years before he did (in Sense and Goodness without God V, pp. 291-348), which I don’t expect him to have known about, but many philosophers were there before him, writing much more sophisticated defenses of it, and taking challenges to it far more seriously, than he did. And I do expect him to have known about them. At least some of them (his book does barely mention a few, but relies on their work almost not at all). I cite many of these philosophers in my own chapter on Moral Facts. One of them is among the most important moral philosophers in history (yet routinely, and unjustly, even outrageously, ignored in introductions to philosophy), the late, great Philippa Foot, author of the book Natural Goodness and one of the most famous papers in moral philosophy, “Morality as a System of Hypothetical Imperatives,” which you can read in one of the finest collections of moral realist philosophers who defend what is essentially Harris’s thesis–only, again, years before he did: Moral Discourse and Practice.
But that shouldn’t matter to the present contest’s value. Who thought of it first is moot. That Harris did a bad job of defending it up to now is moot.
But Benson is right that “Patricia Churchland, [who also] has a PhD in neuroscience” should try her hand at this challenge because “her book Braintrust is what Harris should have written but didn’t.” I do think Churchland has the chops to make a good go at winning the prize (whether she convinces Harris or not). Assuming she disagrees with him (she might not). She is far more competent at philosophy than Harris, and knows the subject superbly well, and treats it a lot better in her book–indeed, I would far recommend it over Harris’s, except that she does not go very far there in defending the thesis Harris is.
Churchland shies away with some uncertainty over whether her conclusions warrant going all the way toward an actual full-blown science of normative morality. Although she is not shy about science being able to empirically discover true normative propositions generally: she explicitly defends that (refuting the “is/ought dichotomy” objection to it); and she’s undeniably right, since science has already been doing this, with superlative success, for centuries–in fact millennia–as I lay out more explicitly in my own chapter on Moral Facts.
One Question to Answer
Contrary to what is implied by Benson’s guest commenter, Marcus Ranum, the question “how do you know your idea of what the common good is is fact and not merely your opinion?” is not any more a valid objection to Harris’s thesis than it is against any thesis in science whatever. And that’s true even for his thesis as actually argued in his book–since he addresses this question there. So as Harris himself says, this cannot be an objection to the argument of his book, because this completely fails to address the answer his book gives to it. You can’t just keep repeating the same arguments he has responded to, without addressing his responses.
Now, I think one might be able to refute (or demonstrate the insufficiency of) Harris’s answer to that question in his book. Like I said, I don’t think his book is the best defense of the thesis one could make (it’s hard enough even discerning the logic of his arguments, much less their premises and conclusions). That makes it essentially a straw man (of Harris’s own making). But that does not mean there is no sound and sufficient answer to that question. I charge that if you really want to prove there isn’t one, you will have to respond to my answer to it in my own chapter on the subject, which, unlike Harris’s, went through several serious critiques by expert philosophers and was developed from extensive (and not contemptuous) research in the relevant philosophical literature, and with a concern for carefully laying out its formal logic (the syllogisms you have to prove invalid or unsound are on pp. 359-64; they formalize what is explained in the text).
But to make the overall point clear, notice that the same question can be asked of any science. For example, in conversation with a schizophrenic, “how do you know your idea of what the real world is is fact and not merely your opinion?” Oh. Right. Now you see the problem? How, after all, can a psychologist know he is not the schizophrenic, and thus deluded as to the nature and contents of reality? How would the schizophrenic come to realize he is the one deluded as to the nature and contents of reality? If the schizophrenic can never do so, or can but never does, does that make the psychologist’s understanding of reality a mere opinion and not a matter of fact?
That may sound silly, but this is a serious question. One cannot say that merely because there will be people who never agree that reality is x, that therefore there is no fact of the matter as to what x is, much less that science therefore has no authority to tell us what x is, and should not even be funded or directed to try. Analogously, that someone might never be convinced that x is moral is not at all a valid argument that x is not in fact moral–objectively, empirically, and scientifically. Just as reality would remain x regardless of who would admit it, so could objective moral facts remain factually x regardless of who would admit it.
You therefore have to apply the same solution to the doctor-schizophrenic relationship in the scientific quest to know the facts about the universe to any scientific quest for moral facts specifically. Just as there are creationists who never accept evolution is fact, so there will be whole groups of people who will never accept what science discovers to be the moral facts of humankind. Especially the dogmatically religious, but not only them. Look at the rabid examples of immovable irrationality among many atheists, from anti-vaxxers and climate-change deniers to Randroids and MRAs; that they will never agree that reality is x is simply no argument against the fact that reality is x. Atheists will stubbornly reject science, when they have been as sold on a secular belief or ideology as any theist has been sold on a religion. But that they reject science does not make the conclusions of science invalid, or nonfactual, or “just the opinions” of scientists. Anyone familiar with Kühn should already have worked this out (and you don’t have to fully agree with anything Kühn argued to get here from there).
In short, if we can answer the “how do you know [x] is fact and not merely your opinion?” question for any x in any other science, we can do it for any x in moral science. And in precisely the same ways.
Breaking It Down Into Easier to Follow Units
Something Harris is really terrible at, I know. But if you want to challenge Harris, this is one way to simplify the problem:
Which of these premises do you reject?
1. Moral truth must be based on the truth.
If a conclusion is based, at all, on false propositions, that conclusion cannot be claimed to be true (it may or may not be true; but if you are deriving it from false propositions, you cannot claim it is true). This holds in morality as much as in any other domain of knowledge. So “how do you know [x] is fact and not merely your opinion?” is answered when x follows with logical necessity (hence without fallacy) from only true propositions. If any of the propositions you are deriving x from are false, x is not a true moral fact (or not known to be). And you cannot legitimately claim otherwise (lest you become a pseudoscientific crank).
2. The moral is that which you ought to do above all else.
This is the most reductive possible definition of moral fact. It is a tautology (as all definitions are), but is valuable and meaningful precisely because of that. If you mean by “moral” something other than this, then you are wasting everyone’s time talking about nothing of any importance. Because if you mean something else by “moral,” I will have this other thing, this thing which you really ought to do above all else, which means above your thing, too, whatever it is. So I will have something even more imperative than yours, and if mine is factually true (it really is that which you ought to do above all else), yours cannot be (it cannot be that which we ought to do…because I can prove we ought to do something else instead).
(If at this point you protest I can’t ever prove anyone really ought to do anything, much less above all else, that that is not an empirical matter capable of scientific demonstration even in principle, then you need to brush up on the basics: both I and Churchland have in that event proved you wrong, and if you knew anything about the role of empirically proved imperative facts in agriculture, engineering and medicine, we wouldn’t have to school you on this point. But alas if we do, go read what we’ve said on it. You can question whether moral imperatives are like other scientific imperatives; but you can’t question that there are imperatives we can scientifically discover and empirically demonstrate. So if any of those happen to be more imperative than all other factually ascertainable imperatives, those imperatives would be by definition moral imperatives, because they would as a matter of actual fact supersede all other factually true imperatives–as well as, of course, all imperatives that aren’t factually true, for the simple and obvious reason that they aren’t factually true.)
3. All imperatives (all ‘ought’ statements) are hypothetical imperatives.
A hypothetical imperative is an imperative proposition that reduces to an “if, then” conditional, such that “if you desire x, then you ought to do y” can be factually and objectively true (and empirically discoverable and demonstrable as such). All that is required is that we prove you do desire x and that y is the only way to obtain x (all variants, such as better and worse ways to obtain x, can be inserted into this structure by broadening and ramifying the set of options designated by x and y). Both are empirical questions of fact which science is more capable of determining than any other method of acquiring knowledge there is.
This concept was first articulated by Kant, who attempted to argue that some imperatives were not of this type but were “categorical” imperatives, but in fact his categorical imperatives all reduce to hypothetical imperatives, so his attempt to prove there was a second kind of imperative failed. Not everyone is aware of this. But I have a demonstration of it (with references to the supporting philosophical literature) in my chapter on Moral Facts (pp. 340-42). Basically, categorical imperatives must either be hypothetical imperatives, or incapable of being true in any meaningful sense.
This is why Philippa Foot developed the fourth way in moral philosophy, showing that morality is actually just a system of hypothetical imperatives (contrary to what many claim, her last work tested the boundaries of this proposition but didn’t explicitly abandon it). When you are taught any intro to moral philosophy (such as in college) you will be told that morality must be one of three possible systems (all invented by men): a teleological system (first fully articulated in the utilitarianism of John Stewart Mill), a deontological system (first fully articulated in the categorical imperative of Immanuel Kant), or virtue ethics (first fully articulated by Aristotle). Foot added a fourth and wholly separate category, which actually is far more plausibly correct.
In my opinion, this is one of the most important developments in moral philosophy in the history of the subject. Hence I find it appalling hers is not included as a standard option competing with the other three. Particularly since it actually subsumes them all into a single coherent system: even Kant’s deontological ethics reduces to a special form of teleological ethics which reduces in turn to a special form of virtue ethics, which reduces in turn to a system of hypothetical imperatives. Thus, Mill, Kant, and Aristotle were all right, they just were missing pieces of the whole picture, and thus failed to see how the defects of their separate systems disappear when their systems are united rather than treated as incommensurable and in competition with each other. The means to unite them is the approach of Philippa Foot.
So you can see why I find the snubbing of a woman philosopher here appalling. There can be no valid reason to exclude her from the status and importance of Kant, Mill, and Aristotle. It’s hard to avoid the conclusion that she was (and pretty much still is) ignored because she was a woman.
Be that as it may, once we restore her to her proper place in the debate, the old ruts of “teleological, deontological, virtue ethics” dissolve into a single unified way to understand moral propositions. The outcome is that all moral propositions (even in Aristotle, Kant, and Mill, and all their successors and emulators) are revealed to be really just hypothetical imperatives. I have never seen any credible challenge to this outcome. (Most philosophers are unaware the outcome was even achieved…because most philosophers ignore Philippa Foot, or make no use of her work–at all, much less to this valuable end.)
4. All human decisions are made in the hopes of being as satisfied with one’s life as one can be in the circumstances they find themselves in.
People can be wrong about whether a decision they made will lead them to greater satisfaction with their life; but if they knew that when they made the decision, they would have decided differently, and chosen instead what would lead them to greater satisfaction with their life. This is observably always the case, even when persons are irrational (as when they willfully ignore more distant negative consequences to pursue present satisfactions) or mal-informed (as when they pursue, for example, money and wealth under the false belief that it will bring them more satisfaction, never realizing that perhaps it doesn’t, or did so far less in relation to the lost satisfactions of other courses that could have been taken instead).
In both cases (irrational and mal-informed decisions) a decision was made in violation of our first premise (“Moral truth must be based on the truth”) generalized to all domains (“Prudential truth must be based on the truth”). In fact, that our decisions are being made irrationally, or that they need to be, is just a special case of making mal-informed decisions (since if we knew we were being irrational, we would either stop being irrational or continue, but in ignorance of the consequences: i.e. if we knew we were being irrational and didn’t stop, then we are either ignoring the negative consequences of doing so, and thus acting on a false belief that there won’t be negative consequences, or we are knowingly preferring those consequences, in which case we have gone full circle and are back in fact to choosing what most satisfies us).
Thus what we must say is that if a person makes rational decisions, then they would make satisfaction-maximizing decisions. So when we assert that “all human decisions are made in the hopes of being as satisfied with one’s life as one can be in the circumstances they find themselves in,” and add the aim to discover true normative propositions about that, then we are assuming human decisions being made rationally. Because irrational human decisions can never be normative (there is a prima facie exception to this, e.g. gameplay, but it is only an exception when subsumed under an umbrella of rationality at which level it is not an exception, e.g. we make rational decisions about when to behave silly and when not to, so secunda facie this is not an exception but in fact only further confirms the rule).
The same goes for human decisions made ignorantly, etc. Any decision made based on false or incorrect information cannot be normative; and when we reintroduce correct information, decisions will only fulfill the rule, and greater satisfaction will be aimed for as proposed. (There is the question at this point of impossible knowledge or knowledge one cannot reasonably have obtained, but when we accept that all imperatives, even moral imperatives, are situational, this problem dissolves–I explain what it dissolves into in my chapter on Moral Facts).
Satisfaction pursuit is a higher level of generalization than Harris and others (including once myself) have used, which is usually “happiness” or “well-being” or “avoidance of suffering” and so on. But in fact we only pursue those things because it satisfies us more to do so–because when it doesn’t, we pursue something else. For example, if it will satisfy us more to die than to do something despicable, we are not violating the expectation that our “decisions will be made in the hopes of being as satisfied with our life as one we be in the circumstances we find ourselves in,” but in fact conforming to it. It’s just that the circumstances we find ourselves in in such a case leave us few and very poor options, and we settle on the most satisfying. Which is not the most satisfying option we can imagine. It’s just the most satisfying option available.
Likewise, when we do good for others, when we make sacrifices for others or for ideals or things other than our direct material needs, when we voluntarily inconvenience ourselves, we do so because it satisfies us more to do so than it would if we didn’t. The reasons for that are complex. But the fact of it seems amply confirmed, and I am not aware of any disconfirmation of it. (For more on satisfaction as the supreme goal in every individual’s life and its role in entailing moral facts, see my debate with fellow atheist Mike McKay–for links and post-debate commentary visit Goal Theory Update.)
This can be taken as an empirical hypothesis about the species Homo sapiens (as Patricia Churchland does). It can also be taken as a structurally inevitable property of almost any survival-capable conscious agents generally (harder to prove, but possibly true nevertheless). For the purposes of challenging Harris, we should give him the best case possible (so we don’t attack a straw man), and that means assuming only that his thesis requires the less ambitious of these options: that this proposition about satisfaction-pursuit is a scientific hypothesis about the species Homo sapiens.
We must therefore ignore all objections that appeal to aliens or robots or other forms of intelligence. Perhaps there are different moralities for them. That would not change what the moral facts are for us (human beings). This distinction will get more problematic when we acquire the power to radically alter the nature of ourselves and the world. But we can set aside that looming problem for now, and just deal with the easier problem in the present case, which is what is morally true for us, as we are right now. (Although we can’t let that other question sit idle for too long. We are not far from its becoming a crucial question that we as a society will have to seriously answer. Harris has said some things on that matter, not very sagaciously IMO, but we are to address his core thesis, not “peripheral issues.”)
5. What will maximize the satisfaction of any human being in any particular set of circumstances is an empirical fact that science can discover.
Here circumstances include the attributes of the person (e.g. preferences and personality and health) as well as the attributes of the conditions they are in (e.g. social status, property, geopolitical location, a mugger attacking them, etc.).
And it should be obvious that combining (1) with (2) produces the empirical question: what would it take for you to be the most satisfied with your life as any decision you make is able to achieve and at the same time all your beliefs (about yourself and the world and the consequences of every action available to you) are true and complete (such that knowing nothing else would change your answer). And the answer to this question is empirically discoverable by science–for any individual, given sufficient access to the relevant information, all of which is a system of physical facts, about you and the world.
Actually achieving that state may be impossible (you will never have nothing but true and complete beliefs). But we will recognize that if any there is any false belief or incomplete knowledge in our minds that is consequentially relevant to how we decide, correcting it will change our decision. And there can be no rational, factually true reasoning that would persuade us to decide differently. There may be irrational or factually false reasoning that would do so. But the output of such reasoning can never be normative (rule 1). And we are asking about what is normative, what we ought to do–in fact, what we ought to do above all else (rule 2).
6. There are many fundamentals of our biology, neurology, psychology, and environment that are the same for all human beings.
While individuals will differ in what makes them most satisfied, all will share some basic needs in common in that regard due to shared biology and environment.
For example, everyone needs to eat. What specifically they as individuals would prefer to eat will differ, but not the general fact of needing to eat. Likewise breathe, etc. And beyond that, emotional and intellectual needs: it will ultimately be more satisfying (and/or more satisfaction-generating) to know how to reason well and be informed (i.e. educated); it will be more satisfying (and/or more satisfaction-generating) to have social company that will help rather than harm you; more satisfying (and/or more satisfaction-generating) to live in a functional society rather than a dysfunctional one (e.g. more economically and politically stable and efficient, less crime and corruption and excessive constraint); more satisfying (and/or more satisfaction-generating) to have some friends and love in your life rather than none; etc.
Even while individuals again differ (e.g. how much company we prefer to seek vs. being alone), the commonality remains despite variations in degree (e.g. the need for some company and to combat loneliness is biologically, neurologically, and psychologically universal; as is the need to work effectively with the social system we find ourselves in and to have a social system that works effectively at all; and so on).
So when we revisit the fact that all ought statements are hypothetical imperatives (rule 3), we will discover that combining (2) with (3), a hypothetical imperative in which the condition (the x in “if we want x“) supersedes all other conditions (there is in fact nothing we will ever really want more than x) is by definition a moral imperative. All human beings want life satisfaction more than anything else (rule 4). And how to achieve that is an empirical question subject to scientific inquiry (rule 5). And some aspects of how to maximize life satisfaction are true for all human beings (rule 6).
Therefore there is something all people want more than anything else, which entails some behaviors all people ought engage in, if they are rational and do not abide by any false beliefs. And those behaviors are moral facts. Which science can empirically ascertain as such. And no competing idea of what’s moral can override them–because any such competing idea would either be them (and thus not in competition with them) or would not be based on true or rational beliefs (rule 1) or would not be overriding and thus would not be moral, by definition (rule 2).
Therefore, Harris’s core thesis is correct. Indeed, it’s undeniable.
Many Devils remain in the details, but that’s the case for all scientific questions, and therefore cannot be an objection to this core result. Look at how messy and open many questions still are regarding the origin of life and the universe, the unification of relativity and quantum mechanics, even matters concerning the mind and brain or just ordinary human biology and biochemistry. We do not “thereby” conclude those questions are outside the purview of science. And as for them, so for difficult or as-yet-unanswered questions in moral science.
And again, likewise, whether people refuse to accept the results of moral science (like creationists do evolution science) also has no bearing on the truth of Harris’s core thesis.
Hence I do not believe anyone can make a valid argument against it.
Whether Harris would know enough to make any of these points is another question. But that’s his own lookout.