The Moral Equivalent of the Parallel Postulate

(Update: further discussion here and here.)

Sam Harris gave a TED talk, in which he claims that science can tell us what to value, or how to be moral. Unfortunately I completely disagree with his major point. (Via Jerry Coyne and 3 Quarks Daily.)

He starts by admitting that most people are skeptical that science can lead us to certain values; science can tell us what is, but not what ought to be. 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 uses an ancient strategy to slip morality into what starts out as description. He says:

Values are a certain kind of fact. They are facts about the well-being of conscious creatures… If we’re more concerned about our fellow primates than we are about insects, as indeed we are, it’s because we think they are exposed to a greater range of potential happiness and suffering. The crucial thing to notice here is that this is a factual claim.

Let’s grant the factual nature of the claim that primates are exposed to a greater range of happiness and suffering than insects or rocks. So what? That doesn’t mean we should care about their suffering or happiness; it doesn’t imply anything at all about morality, how we ought to feel, or how to draw the line between right and wrong.

Morality and science operate in very different ways. In science, our judgments are ultimately grounded in data; when it comes to values we have no such recourse. If I believe in the Big Bang model and you believe in the Steady State cosmology, I can point to the successful predictions of the cosmic background radiation, light element nucleosynthesis, evolution of large-scale structure, and so on. Eventually you would either agree or be relegated to crackpot status. But what if I believe that the highest moral good is to be found in the autonomy of the individual, while you believe that the highest good is to maximize the utility of some societal group? What are the data we can point to in order to adjudicate this disagreement? We might use empirical means to measure whether one preference or the other leads to systems that give people more successful lives on some particular scale — but that’s presuming the answer, not deriving it. Who decides what is a successful life? It’s ultimately a personal choice, not an objective truth to be found simply by looking closely at the world. 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.

Harris is doing exactly what Hume warned against, in a move that is at least as old as Plato: he’s noticing that most people are, as a matter of empirical fact, more concerned about the fate of primates than the fate of insects, and taking that as evidence that we ought to be more concerned about them; that it is morally correct to have those feelings. But that’s a non sequitur. After all, not everyone is all that concerned about the happiness and suffering of primates, or even of other human beings; some people take pleasure in torturing them. And even if they didn’t, again, so what? We are simply stating facts about how human beings feel, from which we have no warrant whatsoever to conclude things about how they should feel.

Attempts to derive ought from is are like attempts to reach an odd number by adding together even numbers. If someone claims that they’ve done it, you don’t have to check their math; you know that they’ve made a mistake. Or, to choose a different mathematical analogy, any particular judgment about right and wrong is like Euclid’s parallel postulate in geometry; there is not a unique choice that is compatible with the other axioms, and different choices could in principle give different interesting moral philosophies.

A big part of the temptation to insist that moral judgments are objectively true is that we would like to have justification for arguing against what we see as moral outrages when they occur. But there’s no reason why we can’t be judgmental and firm in our personal convictions, even if we are honest that those convictions don’t have the same status as objective laws of nature. In the real world, when we disagree with someone else’s moral judgments, we try to persuade them to see things our way; if that fails, we may (as a society) resort to more dramatic measures like throwing them in jail. But our ability to persuade others that they are being immoral is completely unaffected — and indeed, may even be hindered — by pretending that our version of morality is objectively true. In the end, we will always be appealing to their own moral senses, which may or may not coincide with ours.

The unfortunate part of this is that Harris says a lot of true and interesting things, and threatens to undermine the power of his argument by insisting on the objectivity of moral judgments. 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. Science can be extremely helpful, even crucial, in that task. We live in a universe governed by natural laws, and it makes all the sense in the world to think that a clear understanding of those laws will be useful in helping us live our lives — for example, when it comes to abortion or gay marriage. When Harris talks about how people can reach different states of happiness, or how societies can become more successful, the relevance of science to these goals is absolutely real and worth stressing.

Which is why it’s a shame to get the whole thing off on the wrong foot by insisting that values are simply a particular version of empirical facts. When people share values, facts can be very helpful to them in advancing their goals. But when they don’t share values, there’s no way to show that one of the parties is “objectively wrong.” And when you start thinking that there is, a whole set of dangerous mistakes begins to threaten. It’s okay to admit that values can’t be derived from facts — science is great, but it’s not the only thing in the world.

180 Comments

180 thoughts on “The Moral Equivalent of the Parallel Postulate”

  1. Pingback: Darwiniana » Challenges to Harris

  2. Mr. Harris is asking us to be bold enough to take the next step towards equality and potential for self-actualization for all. Just like abolitionists, women’s suffrage, the gay rights and animal rights movement, the idea is that we ALL benefit from others have the same freedoms as the most free. Bravo to Sam Harris and everyone willing to stand up to backward-thinking traditionalists!

  3. Rob
    Mr Harris is leading us down the same tired road of oppression and wanton waste of human life that will occur with absolute mathematical certitude if he is successful in “scientifically” deriving morality. The “truth” of Mr Harris’ flawed logic is well established from the mathematics of axiomatic set theory, and has been well expanded by our friends in computer science. Their a certain level of equivocation that can never be reduced by any structured finite logic system (aka…Euler’s response to Diderot, and the foundation of our concept of God). Sam Harris is unable to understand this, and apparently so are you. In any case, if you try to “maximize happiness” you will quickly find out that mathematically we were happiest before we were born or after we have passed (e.g. minimized suffering). So in summary…zip it.

  4. p.s.
    you might want to start by reading Cantor, Boltzmann, Turing, Goedel, Shannon, Weaver, Weiner, and their specific references.

    As long as I am writing, the phrase “Their a certain level… “, should be “There is a certain level…”

  5. #5

    Always amazing to see how people choose ridicule and belittlement when they are out of argument. They appeal to the inferiority complex they presume is hiding behind the titles and formal merites of every person. Just because they suffer from it so badly themselves. If Sam Harris has obtained a PhD or not is of course of no interest for the debate and for his argument, which have to be met on their own merits only.

  6. @Cheshire Cat:
    “Their a certain level of equivocation that can never be reduced by any structured finite logic system”

    Hence, according to your reasoning (or lack thereof) we shoud stop doing mathematics, physics, chemistry, economics, etc. because there is no guarantee that our axiomatic systems won’t lead into contradiction. Good luck with your project: see you in the stone age.

  7. No…that’s not what I said. Every axiomatic system is guaranteed to eventually lead to incompleteness or contradiction. This is a fundamental proof. It is absolutely essential that our society begins to comprehend the impact this has on our ability to actually control things (and people). There is simply no way for an axiomatic system to fully incorporate all the degrees of freedom in our reality, and we are always forced into states of approximation. We can not as of yet even confirm that there isn’t an hierarchy of sets between our limited logical capability and reality as a whole. It is simply beyond our current mathematical ability to support any science that claims to be able to do what Sam Harris’ suggests, and it is a certitude that it is an impossibility with the limited mathematical tools we have available at present. You need to begin to think on your own and stop listening to all the obfuscation you get from poorly informed media sources.

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  9. The point is being missed here. When one says that ought cannot be deduced from is, one is making a tautologically true statement as Hume demonstrated. However, to deduce from Hume’s demonstration that moral facts cannot be known is absurd. One does so in exactly the same way that one engages in other varieties of scientific discovery. One examines the argument to determine whether it entails contradictions. If it does, then the argument fails (from a faulty premise if nothing else). This is simple to illustrate. Imagine someone who makes the statement that all humans should be kept totally incommunicado because this will build up their individuality. It’s a values based statement but leads to contradiction. No communication is what we otherwise call dead. The values statement is falsified by the nature of the physical existence we lead.

    It is the demand for conformance with an inappropriate standard of judgement that leads to criticisms of the method Sam Harris is using when he treats moral statements as facts. Insisting that Hume’s problem of induction must be solved before we can know anything about values is a mistaken position. Morality can be scientific in exactly the same way that biology is scientific or that chemistry is scientific. That science can be pursued thru a Popperian process of falsfication in the same way any other science may be pursued. Experimental economics has a decent start on it even.

  10. Sean:

    “When it comes to morality, there is nowhere near the unanimity of goals that there is in science. That’s not a minor quibble, that’s the crucial difference! If we all agreed on the goals, we would indeed expend our intellectual effort on the well-grounded program of figuring out how best to achieve those goals. That would be great, but it’s not the world in which we live.”

    When someone says we ought to believe in Creationism because it says so in the Bible, they are using an alternative epistemological program for discovering the truth. (One I consider to be irrational.. Just like I think non-utilitarian models of ethics are irrational. But I’m getting ahead of myself.)

    The same is true for ethics. When a utilitarian says we can have objective moral facts, they are (like a scientist) appealing to certain assumptions and purposes. What’s important (in both cases) is if those assumptions and purposes are “rational”.

    The is/ought problem is sound. You can’t get from facts to values. But it cuts both against normative schemes in epistemology (like science) and normative theories on ethics (like utilitarianism).

    (And honestly, I think that both science and utilitarian thinking have both made drastic improvements in our lives. Many of the things Jeremy Bentham argued for a few centuries ago, like equality for women, animal welfare laws and decriminalization of homosexuality, are generally accepted. )

    Just to beat a dead horse:
    1.) Santa Claus is a self-contradictory character. (fact – descriptive)
    2.) We ought not believe in self-contradictory things. (value – prescriptive)
    3.) Ergo, we ought not believe in Santa.

    1.) Having the burka be mandated leads to less happiness in general for women. (possible fact – descriptive)
    2.) We ought to promote general welfare. (value – prescriptive)
    3.) Ergo, we ought not demand women wear burkas.

    How are these two different?

  11. @Cheshire Cat:
    I do think for myself, thank you. I’ve studied Gödel’s theorem, and find it both fascinating (as an intellectual achievement) and useless (as a practical tool). It is certainly irrelevant to Harris’s point, which is not concerned with formal axiomatic systems and statements that assert their own unprovability, but with the pragmatic, pedestrian realities of daily life.

  12. Sean, if you would kindly(just for a moment, because i realize you enjoy keeping it there) remove your head from your ass. Before you bash a potentially valid theory, would it be too much to ask if we engaged in a 21st century conversation about good ideas and bad ideas.. and how these ideas directly affect our world? and our future? Why can’t we have a discussion(which is what Mr. Harris is begging for) without being so quick to go to war with his ideas. You obviously imagine some sort of scenario where scientists in labs with beakers are determining what church you should go to… I’m finding a hard time believing someone could think in these simple terms. It could be that you didn’t like him or his ideas before he even spoke on this particular subject.. I’ll go ahead and assume that.. lest i assume something much more repulsive.

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  14. piero
    I would have to disagree with you. We have an inherent problem with the communication of moral codes. If we accept that not everyone has the same concept of morality, then we have an implicit need to be able to symbolically express moral statements. As soon as we take this step we run face to face with all the issues explored by Church and Turing in their resolution of the Hilbert decision problem and Oracle machines. We run into a moral paradox of implementing a moral standard that we can never verify as always providing moral answers to questions.

  15. I have been quite busy for some time, and it is perhaps too late to reply. Just a couple of observations:

    1) I believe that Harris’ completely uncalled bitchy response to this very post proved my point about his intellectual openness.
    2) I am no stealth believer, don’t know how to prove it but I can simply restate it.
    3) There is nothing like a pure ‘issues’ discussion. Within reason, academic qualifications do count. And so does a personal political agenda. And boy, Harris has a big one.

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  17. From Sean’s original post:
    “There is a old saying, going back to David Hume, that you can’t derive ought from is. And Hume was right!”

    Right. But humans are moral creatures and that morality evolved because it was beneficial for survival of the species. Science can propose and test various hypotheses concerning our morals and how they serve to ensure the continuation of the species and how they evolved.

    Science can also test how the application of laws based on different moral codes affect individuals and groups. Why is it not possible to have a science of morality?

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  20. Ha, reading through this heated thread one wonders where the relativists think morality comes from? I guess it would have to be a divine source or a mystical spirit, if it can not be observed and measured, and if there are no ground rules that drive those functions in our individual brains. So is “what ought” somehow streamed magically into our new-cortex from somewhere where physical law does not govern?!

    As the great Galileo said “Measure what can be measured, and make measurable what cannot be measured.” Everything can be, and should be, boiled down to its physical laws, with the limitations of the uncertainty principle of course, and I don’t see why the uncertainty principle of sub-atomic particles would play a role in morality.

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