Moral Hazard of the Multiverse

By Sean Carroll | February 11, 2011 9:30 am

Brian Greene was on the Colbert Report the other day, promoting his new book The Hidden Reality. Little did he know (one presumes) how much he was endangering the moral fiber of today’s youth.


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Brian’s book is about the multiverse, a hot topic these days in cosmology circles. I haven’t had a chance to read it yet, but he is one of the clearest and most level-headed people we have writing about modern physics, so I’m sure it’s worth checking out.

We’ve certainly touched on the multiverse idea on this very blog, for example here and here. It’s a controversial topic, as you may have heard. People worry that talking about unobservable things is a repudiation of what it means to do science, a symptom of the decadence of modern society, etc. Click the links to rehash the usual debates.

But a new rhetorical strategy has appeared among the anti-multiverse crowd — not that the idea is wrong (which would be very interesting, if there were a good argument for it), or even that it’s nonscientific (the usual complaint), but that it’s immoral. We are actually violating the Categorical Imperative by talking about universes beyond our own. Points for novelty!

Or not. The immorality argument was recently advanced by John Horgan and Peter Woit. But if you read the posts, it’s the usual curmudgeonly sniping, with the shrillness knob turned up a click or two. The actual argument is the same as it ever was: talking about unobservable things is not science. [Update: Peter explains his objection here.]

However, a truly novel version of the immorality charge was leveled by Clay Naff at the Huffington Post. Naff introduces a “moral principle,” which informs us to “resist accepting any proposition that tends to disable moral reasoning, unless and until the scientifically interpreted evidence compels us.” That is, instead of judging ideas by our conventional criteria of whether they are likely to be “right” or “wrong,” we should include an additional new factor that weights against ideas that would disable morality.

Hopefully the problem with this idea is immediately evident: ideas about how the universe works can’t possibly “disable moral reasoning.” The world does whatever it does, quite independently of our moral judgments. The job of morality is to figure out what we think we human beings should be doing, which, as we’ve been discussing, does not reduce to looking at what actually happens in the universe.

Of course, what counts as a moral action certainly depends on what actually happens in the universe. (Saving lives would be less urgent if everyone who dies goes to Paradise in the afterlife.) But Naff’s worry is a little funny. What he seems to be concerned about — although he never quite comes out and says it, so a bit of interpretation is required, and I could always be misreading — is the possibility that our moral intuitions could be undermined by the idea that there are an infinite number of copies of ourselves out there in the multiverse, some of them exactly like us and many of them slightly different, e.g. worlds where Hitler was victorious, etc. In such a setup, should we be concerned that morality is pointless, because every good thing and every bad thing eventually occurs elsewhere in the cosmos?

I don’t think we should be concerned about that (even if it’s true, which it may very well be). An idea like this doesn’t “disable our moral reasoning” — in fact, it might be extremely helpful to our moral reasoning. If your version of morality depends on the assumption that what happens here on Earth is unique in the universe, then it’s time to update your morality, not to put your hands over your ears when people start talking about the multiverse.

The real problem with Naff’s position is its fundamentally paternalistic tone — even if, to his credit, he seems to include himself among those who need protection from these scary ideas.

The danger lies in how they take root in popular culture. If we come to believe that choices do not matter, that any action is matched by its opposite somewhere, we risk losing our capacity for moral reasoning. History shows that, inbuilt though that capacity may be, ideas can short-circuit it.

In short, what I am saying is that those of us who are NOT so brilliant as to be able to follow the math need to resist being seduced by visions of parallel bubbles in a multiverse.

I have this old-fashioned notion that if an idea about the universe is very possibly correct, there is no moral or scientific advantage to pretending otherwise, even among those who can’t follow the math. Our capacity for moral reasoning shouldn’t depend on what’s happening many googols of parsecs away in an unobservable part of the universe. If it does, our moral reasoning needs an upgrade. And if reading popular books about the multiverse help nudge people along that path, I’m all for it.

  • Blake Stacey

    For reasons which aren’t worth going into right now, I’m more sympathetic to the inflationary-cosmology flavour of multiverse than the Everettian kind; however, I agree that research on either topic is neither unscientific nor immoral. (I expect that there is no necessary contradiction in favouring, for example, a topos-theoretic propensity interpretation of quantum probability while also finding eternal inflation plausible.) If anything here is morally problematic, indicative of lax intellectual standards or unconducive to scientific progress, it’s the disregard for the scientific reasons why people consider multiverses and the misrepresentation of their thinking.

    Business as usual at the HuffPo, I suppose.

  • Matt B.

    So maybe, according to this line of thought, the Catholic Church is right to say that thinking about committing a sin is as bad as the act itself. If the immoral action is not possible, because your mind is pure, then there will be no universe in which you commit that action.

  • kiwidamien

    I don’t know if I would agree that ignoring an idea that is correct means there is no scientific advantage to pretending otherwise.

    Currently in physics we have the notion of an effective field theory, in which we knowingly write down a low energy approximation ignoring details that only become relevant at higher energies. You could easily argue that this is not the same thing – by construction an EFT acknowledges the existence of a greater theory by the fact it (typically) breaks down at some scale — or that the theory “predicts its own demise”. You could also argue that the EFT allows us to calculate close to the cutoff scale and invites us to think about what could possibly fix it. I would argue that, at least as written, we are ignoring things about the universe (higher energies) and using an approximate technique to extract information — thus yielding a scientific advantage.

    I think what the above paragraph points out is that a case can be made for EFTs violating the letter of your statement, but I think we both agree they don’t violate the spirit of it. I think there are objections to even the spirit of the argument, however. If I was allowed to send one message back into the 1600s (say 5 seconds long) there are a bunch of things I wouldn’t say. For example:
    * You can change elements from one type to another.
    [A true statement from nuclear physics, but the development of chemistry benefited greatly from the assumption that elements could not change. Such an accepted truth lead people to think about chemical reactions to turn lead into gold via “conventional chemistry” setting research back.]
    * Physics may not be deterministic
    [Depending on your flavor of QM interpretation, or how you interpret deterministic within a decoherence world view. However the development of physics benefited greatly from assuming that there was a deterministic world to study.]

    I would be interested on your views on the above.

  • Brian C.

    Multiverse-induced amorality is both silly, and old news. It was also very silly in 1971 when Larry Niven wrote the story All The Myriad Ways about it (google, you’ll find it).

  • Herb Myers

    The moral argument in considering alternate universes must recognize that the me in this universe is subject only to the the laws and mores of this universe. What I do elsewhere/elsewhen are subject to those laws and mores. To me they are by their nature exclusive.

  • CaliFury

    For those troubled by the moral question of the multiverse:

    “All you need to know is that there is a Multiverse and you are not it.”

  • http://q S

    David Lewis famously defends the thesis that all possible worlds exist. Some have alleged that his position, if true, leads to moral indifference (see section 2.6 of Lewis’s book, On the Plurality of Worlds). It seems that someone *could* raise a similar complaint about loose talk of a multiverse.

  • joe

    It is our moral imperative to travel to every other universe and stop all Hitlers!

  • http:/ Non-Believer

    I agree with you Sean. Either we choose to explore the universe and all of its implications or we cower in the corner and revert to believing in tree sprites whenever we find something that makes us uncomfortable.
    People thought atheism would lead to amoral behavior. It didn’t. Whatever compels humans to choose to live in a civilized and cooperative society, it is not the idea of morals. I would posit that its the need to survive. And in order to survive we agree that certain behaviors are not tolerated or productive.
    Placing moral behavior in the context of whether my bizarro world twin is actually killing babies right now, is pointless. I (the person in this world) have to live with the consequences of actions in this world. And if I wish to survive, I must cooperate. So even if I take a fatalistic attitude of “a bad choice is happening anyway in some other universe”…I don’t have to live in that universe – I have to live in this one.

  • Paddy

    John Bell said about the many-worlds theory: “if such a theory were taken seriously, it would hardly be possible to take anything else seriously”. (in Quantum Mechanics for Cosmologists, 1981).

  • James

    Hang on, I can view it! They’ve ended the rights restrictions in the UK! Halleluyah, praise the lord!

    And an end to Mubarak in Egypt as well. What a day.

  • Noel

    The number of universes (and “alternate” selves) has absolutely no rightful effect on an individual’s morality. Never mind Kant’s Evil. Morality serves the interest of the individual (the furtherance of his existence as man, and all that properly implies); his decisions and their consequences affect the corresponding reality. He is neither beholden to his alternate selves, nor they to him; they can’t be.

  • Anonymous

    I for one, if given the option, would prefer to live in the most moral of all multiverses, and will make my choices to promote that end result… It’s like saying that because there are bad neighborhoods, everyone should stop trying to build good ones. What utter twaddle.

  • Blake Stacey

    The evidence supporting any new scientific idea is rarely, if ever, conclusive. Instead, the data pointing to the new idea are typically equivocal, open to reinterpretation and bedecked with large error bars. If we refuse to consider unpleasant hypotheses “until the scientifically interpreted evidence compels us”, we will deny ourselves the chance of progress.

  • réalta fuar

    It’s hard to know what to make of this post. If one follows the link to Peter Woit’s comment on this, you’ll find that he actually SHARES Sean’s views concerning personal morality in terms of the multiverse. Sean correctly summarizes Woit’s points in his next two sentences, condescendingly, after having written “The immorality argument was recently advanced by John Horgan and Peter Woit.” Woit, at least, did no such thing. It’s clear that Sean knows this, so why in hell did he write that sentence?

  • Shecky R.

    Both Woit and Greene are professors at Columbia… I’ve often wondered if that makes for any interesting encounters in the hallway, or cafeteria, or faculty meetings etc…. (not that profs at a university can’t have opposing viewpoints, but just wondering… it didn’t work very well for Gould, Lewontin, and Wilson at Harvard).

  • ChuckWhite

    It seems to me that all this concern about the moral implications of a multiverse is a tempest in a teacup.

    After all, what is the difference if we propose multiple universes or if we propose Buddhist, Christian or Islamic moralities? Isn’t that spread of moral views threatening enough to moral purists? Really … if you’re a moral purist, *anything* and *everything* can *possibly* threaten the moral sense of the average person … depending on the person.

    If such *threats* are of concern to a person who is moral-centric, I suggest spending the remainder of their lives meditating in a cave, on a mountain somewhere.

    For the rest of us, facts are things to be proven, morals are to be lived by and only when facts require changes to moral values shall the two meet.

  • psmith

    Some 65,000 years ago we started migrating out of Africa. In the 65,000 years that followed we have explored, expanded into and filled every nook and cranny on this planet. That long experience has changed us into beings that are compulsively curious explorers. And as our mind expanded we explored ideas as well as geography.

    So, however much Naff and others may rail against untested ideas, we can’t deny our exploratory instincts and nor should we.

  • Naked Bunny with a Whip

    @Brian C.: At least in Niven’s story, people could experience the alternates directly, making them less abstract than current multiverse hypotheses.

  • Brian Too

    The problem with the multiverse theory isn’t that it is amoral. It is that it isn’t falsifiable.

    String theory flirts with the same problem set.

  • Amos Zeeberg (Discover Web Editor)

    It’s a little like the claim that if humans evolved from other apes, that means humans aren’t God’s chosen special creations, and there’s no hope for morality, so stop talking about that.

  • Peter Woit


    In my blog posting that you link to I was reporting on what Smolin and Horgan had to say about morality and the multiverse, and noting that I disagreed with them.

    I’ve only one concern about the multiverse that has to do with morality, and I tried to make that clear. When it became well-known that string theory unification was an idea that couldn’t be used to predict anything, standard scientific ethics would indicate that those promoting the idea should admit failure and move on. Instead what we’ve seen is a turn to multiverse models constructed purely to avoid predicting anything. This is pseudo-science, and the way it’s being done and the motivations for doing it raise a moral issue.

    If you feel that this is shrill, so be it. I think you’ll find though that there’s a significant fraction of the scientific community that shares my concern. They may not know the ins and outs of the string theory story, but they can see the heavy public promotional hype surrounding an idea that makes no scientific predictions, and strongly suspect something not kosher is going on.

  • Peter Woit

    Shecky R.,

    Brian and I have known each other for over 20 years, and have never had any trouble getting along fine despite our disagreements. He’s a very nice, easy-going guy, and I’m not so hard to get along with either.

  • Eugene

    I never understood the “multiverses cannot be observed” crowd. We don’t even have a Standard model of the Multiverse, how do we even know how to predict whether it can be observed or not?

    The multiverse is not a theory, it’s just the consequence of following the rules of several different, disparate ideas that we know to be right or think it has a chance of being right.

  • Sean

    Peter, I did not say that you agreed with Horgan. I said that you mentioned moral concerns about the multiverse, which you did. As to shrillness, you started your own blog post with “[Warning, somewhat of a rant follows, and it’s not very original. You might want to skip this one…].”

  • spyder

    I find i am much more in agreement with Emeritus Professor Richard Garner (cached file since this is from a subscription site).

  • Peter Woit

    “The actual argument is the same as it ever was: talking about unobservable things is not science. ”

    I’ve never made that argument anywhere, it’s not something I think. I spend most of my day thinking about possible uses of abstract mathematics in fundamental physics that use very much unobservable quantities.

    If your multiverse is not going to be pseudo-science it has to be part of a framework that can be scientifically tested. A standard argument is that the multiverse is science because it is part of the string theory framework, so, test string theory and the multiverse follows. The problem is that you can’t test string theory, and the multiverse is invoked as the excuse for that. That’s why this (string theory + multiverse) framework is pseudo-science, not because other parts of the multiverse are unobservable.

  • psmith

    Sean said “The immorality argument was recently advanced by John Horgan and Peter Woit.“.
    That does seem to be tarring them with the same brush.

    But regardless, the status of multiverse theory as ‘pseudo-science’ is an important debate we should be having.

    We certainly should be entertaining and following a great variety of ideas. The counter-argument, in this case, is that speculative ideas have been excessively popularised, creating an artificial acceptance and elevating them to the levels of pseudo-science.

    Yes, we should be exploring the world of speculative ideas but should we be so actively advocating them and popularising them when they lack evidence? This is at the heart of Peter Woit’s moral concerns. It is an important issue and should be debated.

    We need to be careful with words. Labeling a something as a ‘moral concern’ is not quite the same thing as calling it ‘immoral’ which carries very different implications.

  • Bee

    The “moral argument” would forbid you to accept any fundamental theory with fully deterministic evolution. If you have no free will, you’re arguably not responsible for your actions in any meaningful sense. Instead, it’s the initial conditions of the universe that are responsible. (Or the final conditions for that matter.) So. What now? Cut funding for everybody who dares to believe time evolution is fundamentally deterministic because the philosophical implications are sociologically difficult?

  • Shecky R.

    My (very limited) understanding of all this is that string theorists view their work as science because it is mathematically-grounded; and even if it is untestable and unfalsifiable now, it still may be so at some more advanced stage in the future. I’m not clear, is it Peter’s contention that the subject matter is inherently and forever untestable, and thus worthy of the term “pseudo-science” (a term that must rankle people like Sean), or simply that the current state-of-affairs is untestable, making the term applicable for the time-being?
    (I’m not really interested in the whole “immorality” argument, but am interested in the “pseudo-science” designation.)

  • JK Finn

    “If your version of morality depends on the assumption that what happens here on Earth is unique in the universe, then it’s time to update your morality, not to put your hands over your ears when people start talking about the multiverse.”


    Let’s see, then. What I decide now will irrevocably select a branch for this universe from now on. Which branch would I like to be on?

    How is that not a workable basis for a workable morality, albeit an openly selfish one?

  • Low Math, Meekly Interacting

    I’ve never understood why this is so difficult: There are always things that can’t be observed, but they may have observable, testable consequences. The unobservables are a component of a theory that makes new, testable predictions, and must accommodate all other established observations at least as well as the current state of the theoretical art. I would say anything that does not meet those criteria has not achieved the status of scientific theory. Period. Call it whatever else you like, if words like “theory” and “science” are to have any meaning at all, they have to have definitional constraints that preserve their integrity.

    Nothing about multiverse-dependent speculation that I have ever seen strikes me as even qualifying to aspire to theory, so distant and remote are their chances at predicting anything we can possibly observe. Even more disturbing, no matter how many proposed observational signatures fail to materialize, nothing seems to deter the field. Instead of being more constrained, the underlying principles these ideas have established for themselves appear to allow such an enormous range of escape routes that it’s impossible to ever be content that the idea has been falsified. If this isn’t “unfalsifiability” in absolute principle, it find it hard to believe it can be anything but that in practice. At the end of the day, in science, I should think that “in practice” is all that matters.

    Because of these developments, many who study the multiverse appear to be re-defining what is “scientific” in a way that accommodates their speculation however it may evolve in the intellectual realm, rather than feeling constrained by the physical one. If this isn’t a paradigm shift, I don’t know what is.

  • Thomas

    I just think these concepts are damaging for the public perception and support for science.

  • Antiwoit

    You try to take a cynical view of everything but you dont have anything significant to contribute rather than not very original rants (so your disclaimer is redundant).And it seems your abstract mathematics has not gone anywhere in the last 20 years.

    I think the multiverse idea is at least worthy of discussion. I have no idea how these self righeteous people can declare any discussion of speculative idea as immoral. This is crazy!

  • Clay Farris Naff

    Oh, well done, Sean. You tore that straw-man version of my argument to bits. You quote my principle, and then restate a cartoon version of it that is in direct contraction to my essay. Where’s the intellectual integrity in that?
    Let me remind you of two things in my essay: first, I clearly state that we should not flinch from the pursuit of and acceptance of truths, however troubling they may be. To be concrete about it, I state that even if the worst slurs heaped on evolution were true, I would defend it, because the evidence for it is overwhelming. Second, I make it perfectly clear that I have no quarrel with Brian Greene or the pursuit of multiverse studies. Rather, I am warning against the facile adoption in pop culture of *conjectures* that may or may not be true, and even if true may be only part of a larger truth. Listen to Greene’s interview — he says much the same to Colbert.
    Finally, since you seem unable to imagine the moral hazard that can arise from mistaking the infinite multiverse conjecture for fact, let me offer you a scenario: suppose that you truly believe that there are infinite copies of yourself “out there,” including every possible variation of your life history. Now, suppose I offer you a million dollars to play Russian Roulette with a gun that has five of six chambers loaded. Would it not be rational to take the bet? And so, would it not be rational to abandon “this” life at every frustration or mistake?
    Just because this is counterintuitive does not mean you can brush it aside — as anyone who respects science should know.


    Clay Farris Naff

  • Ed Pearlstein

    A truly moral world would be one where “Nature red in tooth and claw” doesn’t apply

  • Eric Habegger

    I recently was listening to a “This American Life” episode. It was about a few real estate loan agents pressuring customers to take loans they really couldn’t afford. Most of these loans had low initial teaser rates and would then blow up down the line. Many of the young agents resisted doing it and their bosses would get upset. The argument from them was “if you don’t make the loan somebody else will and they will make the profit and you won’t”.

    This is definitely a philosophical stance one can take on any question that requires a decision. This framework is specifically modeled in Everett’s Many Worlds theory. Each decision invokes a splitting of worlds where the proportion of worlds roughly splits into the probability beforehand of the different decision events occurring. So if one takes the MW idea as actually true one does effectively remove the moral component in decision making. Who’s to say that all those bosses in finance didn’t actually know about the MW interpretation of physics when they said to themselves “if you don’t do it somebody else will?

  • Torbjörn Larsson, OM

    The problem is that you can’t test string theory, and the multiverse is invoked as the excuse for that.

    Feh! String theory is in principle testable on some scales, multiverses are testable now or soonest (as Sean has invited guest bloggers to discuss), so there is no principle of physics or morals involved.

    “Pseudoscience” you can claim when it isn’t science, and when it isn’t science (say, because no practical method of testing appears) is an outcome of scientific community behavior and not a matter for individuals.

    If there is a problem of morality it is for Woit. He induces people to think string theory is not main stream science, which is a problem for science and education both. Yet legal principles (often founded in principles of ethics, seldom or never in moral behavior) say that there is freedom of speech. But we don’t have to pretend we like the behavior!

  • TimG

    Even if I believed there were infinite copies of myself out there, I’m still not taking that Russian roulette bet. Because guess what, *this* copy happens to be one I’m especially invested in. I’m pretty sure most people feel that way, and will continue to do so, multiverse or not.

  • Torbjörn Larsson, OM

    So if one takes the MW idea as actually true one does effectively remove the moral component in decision making.

    It doesn’t work that way.

    First, you haven’t solved or even answered the is-ought fallacy that Sean points out.

    Second, even if you did this, the idea shows a blatant misunderstanding of MW and evolution both. If there is no reasonable or accepted probability measure over MWs yet, as Sean’s links shows discussions of, you can’t make uncontested claims out of its probabilities. And since there are probability measures over evolution (likelihoods of behavioral traits, fitness) that precisely describe what different species find as innate “moral” behavior, it isn’t affected by the existence of MWs.

    I hope the “philosophical stance” was a jest, because morals and science are empirical matters and need empirical answers. Philosophical concerns such as “is-ought” merely brings out the relevant difficulties, they are incapable of actual answer. (For the same reason as religion, because there are many equally valid “truths”.)

  • Eric Habegger

    Well, I don’t think it is a misunderstanding of either MW or evolution. For one thing evolution does not specifically model the survival of the fittest “individual”. Survival of a community requires cooperation within the community also. Even ants cooperate among themselves to insure survival of the community. In my opinion people who embrace the MW philosophy most literally tend to ignore this and embrace it for more or less selfish motives. And many of these people probably never heard of MW but they are never the less following it. But they are misapplying it because they think it follows from evolution. Actually the more we learn about evolution the more we learn it is often about aggregation of individual entities into communities of cooperating entities.

    So I think individuals like you who concentrate choice at the individual level rather than at the community level are those most likely to embrace MW. It is a misunderstanding of both.

  • Eric Habegger

    I guess I should add that I know the difference between MW and 10^500 multiverses in string theory. They are two different things. I don’t agree with string theory for reasons others have put forward – that it is unscientific. It is only the MW framework that I consider amoral and that it often forms the excuse for immoral action, whether it is consciously done or not.

  • Clay Farris Naff

    A note to some of the breezy detractors who’ve commented: it is appalling to find among scientifically literate people such a poor ability to come to grips with the argument presented. Antiwoit rants about “self-righteous” people (presumably myself, for one) declaring “any discussion of speculative idea as immoral.” But that is not at all what I said. Blake Stacy says, “If we refuse to consider unpleasant hypotheses “until the scientifically interpreted evidence compels us’.” I could not agree more, but again that is not what I said. Bee writes, “The “moral argument” would forbid you to accept any fundamental theory with fully deterministic evolution.” Nonsense, as the principle itself makes clear. So, what’s going on?
    My hunch is that many of you feel that I am attacking science (perhaps out of religious motives), and so you’re eager to sweep my argument into the Creationist bin. But you’d be wrong. I’m a devoted supporter of science who, it so happens, is not religious at all.
    The argument I am making has everything to do with the premature adoption of a conjecture as scientific fact in the popular consciousness. Can this do harm? History demonstrates it. Leave aside “Social Darwinism.” I presume that none of you would deliberately torture a sick child. Yet, early in the 20th century, the premature adoption of the scientific hypothesis that *starvation* could cure juvenile diabetes led to horrific maltreatment of already suffering children. You may scoff at the notion that MW as a worldview (rather than as a scientific hypothesis) can have terrible consequences, but I can only say that it shows a poor understanding of history, moral reasoning and/or the social impact of ideas.


  • Ed Pearlstein

    I can’t get excited about whether something mathematical is “science” .

    String theory is mathematics. If it can be shown to describe the real world, then it becomes physics. That’s OK with me.

    Here’s an example of the above: Riemann investigated the mathematics of curved spaces. At the time it seemed to have no correspondence with the world we know. But along came Einstein, who used Reimannian geometry in his general theory of relativity, which certainly is science.

  • Albert Zwiestein

    Never trust anyone who publishes popular pseudo-science books.

    They have made the Faustian bargain [i.e., sold out to mammon and celebrity].

    Then the devil collects his due by having them fall prey to their own Platonic fantasies.

    It is especially sad when this happens to people who start out as good and gifted scientists.

    Albert Zwiestein

  • Antiwoit

    Brian Greene (although he is not very active anymore) has played an important part in physics. While many other “Albert Zwiestein” were sleeping in their mother’s basement searching clever words to insult good scientists, Brian Greene and others like him were discovering Mirror Symmetry in string theory. People like Hawking and Brian Greene are not Faustian but excellent spokesperson for theoretical physics. Greene acknowledges that his work is speculative but nonetheless interesting area which many good people in physics are thinking about.

    I am completely flabbergasted when people who do not even write one serious paper in theoretical physics claim that they are the vanguard of morality in science. What a world, what a life!

  • Ray Gedaly

    Catch-22: If we refrain from considering the multiverse, then by definition our counterparts in another universe will necessarily be speculating about it.

  • AnotherSean

    I agree completely. Absolutely nothing of moral value follows from the multiverse that wasn’t already implicit in science long ago. Frankly, although I think it “exists”, I’m not sure anything scientific follows from it either, other than as a fairly generic prediction. And your right about Brian Greene’s book. In my opinion, it is extremely even handed and well written. In fact, if I have any complaint with Brian’s books its that they are often a little too even handed, particularly in matters of alternatives to QM.

  • Albert Zwiestein

    Scientific theories lead to testable predictions that are well-defined [i.e., not “plastic”].

    Pseudo-science cannot make such yes/no testable scientific predictions. It waffles, at best.

    If you like pseudo-science, feel free to wallow in it.

    But please do not call it science. And do not sell it to the credulous as science.

    As for morality, where is the morality in leading a generation of promising physics students into the swamp of pseudo-science from which few escape intact?

    Finally, does anybody worry about the correlation between rise of pseudo-science and the decline of progress in theoretical physics? If you sincerely care about science, are you not more than a little worried about where this trend is heading?

    Albert Zwiestein

  • Nullius in Verba

    Whether the Everett-Wheeler Interpretation (EWI) – I hate the “Many Worlds” misnomer – has moral implications is an interesting question. There’s no reason why it shouldn’t, and there’s no reason why science or its consequences could never be moral or immoral, although that has nothing to do with its truth. It’s hard to imagine with fundamental physics, but it’s certainly true of medical science.

    Moral beliefs are based on a combination of systematic justifications combined with social conventions, operating on a lot of inbuilt instinct. These justifications can interact in various ways with knowledge of how the world works. Somebody could argue that under EWI the person you see is only an infinitesimal fraction of the full “multi-person”, and so to murder them is to kill only an infinitesimal part of them. If the generally accepted arguments against murder are the end of a unique and irreplaceable life, then this might be a valid argument. (I think that’s a lot more plausible a scenario than the suicide question.) Another question that bears on moral justifications is that of free will and determinism. Are you morally responsible for your own actions in a deterministic universe? It depends on the moral system – some say yes, others no.

    As for EWI being testable – in one sense it has already been tested, and in another the question itself is unscientific. EWI is an ontological interpretation of QM, it predicts only what QM predicts, and as such, is exactly as “true” as QM. The simple “test” of it is to ask in the double-slit experiment, whether the electron as it passes through one slit is electrostatically repelled by its counterpart passing through the other? Can it “see” it, or the other particles affected by it, in the sense of being able to interact electromagnetically with them? If the answer is ‘no’, then you have two parts to the universe that cannot see one another, which is precisely what the EWI extends to the rest of the universe. If you can accept that the electron is not affected by the electric field of its quantum alternative, and yet both exist simultaneously, you have already accepted the basic principle of EWI.

    EWI can perhaps be best understood as a sort of “normal modes of vibration” arising from the interaction (observation) of one quantum oscillator (the observer) coupled temporarily with another (the observed). The particular modes of oscillation will depend on the details of the interaction, (and to some degree the observer,) but being orthogonal, will not be “aware” of one another. They’re not really separate universes – the name is terribly misleading in that regard – but separate parts of a single universe that happen not to interact with one another. We’re not creating gazillions of entire universes out of nothing, all we’re saying is that waves can cross without affecting (‘seeing’) one another.

    EWI doesn’t have anything much to do with the perceived problems with string theory – this is really to do with the use of the anthropic principle to avoid having to provide explanations, which I fully agree is an unscientific cop-out. But not providing explanations for everything is no reason to reject a theory as an intermediate, incomplete theory, unless the alternatives on offer do, and not providing tests at experimentally accessible energies does not mean it is ‘unscientific’ to work on it, although it would be unscientific to accept it as the way the world works.

  • Antiwoit

    What trend? There has always been speculative ideas in science. Science is not just some automated process of just theory and experiments. There is enough room for imagination in science and also interpretation. However, all imaginations, opinions and interpretations are not created equal in science. The real worry for science is people like you and Woit play the loudest trumpet with sound bites about what is moral physics rather than actually studying and contributing to physics seriously.

  • psmith

    #51, Antiwoit says “There is enough room for imagination in science and also interpretation. However, all imaginations, opinions and interpretations are not created equal in science.

    Indeed, they are not equal. What differentiates them is the evidence, fragments or hints of evidence, or at least the potential for evidence.

    But for how long are we going to blunder down a speculative trail with no hint of evidence at the end of the trail?

    And should we be so actively popularising this speculative trail? This objection is at the heart of Peter Woit’s objections and I don’t see anyone addressing Woit’s core objection. Before we start thrusting beliefs into the public consciousness there should be a real basis for believing in it. The more unsupportable speculation we plant in the public consciousness the more we weaken public trust in science and we give pseudo-science supporters more encouragement.

    By all means research any direction you believe in but I suggest that it is not responsible to excessively popularise ideas that, for the time being, have no hope of being demonstrated.

  • Antiwoit

    dear psmith,

    if an idea is sufficiently interesting such as string theory and it does not please the Woits of the world, you cannot really expect people to just abandon it and work on something so that one can regain trust from public and Peter Woit. here physicists should really learn from mathematicians- they dont just abandon trying to prove Poincare conjecture or Fermat’s theorem just because it had crossed some artificial twenty years deadline imposed by some outsiders like Woit. Sometimes a really good idea takes years to understand.
    if an idea is as interesting as string theory, we ought to do our best to understand it.

  • Albert Zwiestein

    Unfortunately, it also appears to take 30 years, or more, to get rid of a really mediocre idea, and its increasingly demented progeny.

    When science is operating properly, this should not be the case.

    By any chance are you from the What Me Worry school of physics?

    Albert Zwiestein

  • psmith

    #53, Antiwoit says “if an idea is as interesting as string theory, we ought to do our best to understand it

    Yes, I absolutely encourage you to pursue ideas that passionately engage you. We can’t foretell where the next big breakthroughs will happen.

    But we do this in the science arena where our ideas will be vigorously examined, tested and criticised. It can get pretty rough in this arena but this is where the dross will be weeded out.

    It is the science writers who move ideas out of the science arena into the public arena and they perform an important function. Among other things, this allows the society at large to decide what proportion of the national treasure to deploy in the service of science. And, as Woit and others mention, these ideas also shape the public consciousness and values. Remember that people in the public arena are not equipped to judge these ideas on their merit. So they must necessarily attach a lot of trust to the science writers.

    Therefore, by and large, the ideas that move out of the science arena into the public arena should have discernible merit. If the idea has not progressed to that stage, leave it in the science arena where it can be subjected to continuing examination and debate by the people equipped to do so. This, at least, is how I understand Peter Woit’s argument.

  • The Numbers

    1+dx does not equal 1. I am unique even if there is some infinitesimally similar variant of me. This is the inescapable moral predicament.

  • Joseph J Veverka

    The discussion over multiverses is proof that we Americans have too much time on our hands. Multiverses were conjured up to answer what came before the big bang. Well what came before the multiverse? The super verse? Really, turn off your computer once a week and go help make this universe a better place. It’s the morially correct thing to do.

  • Doug

    I’m baffled by the persistence of the idea that in an infinite multiverse every physically possible universe must exist. Mathematics certainly doesn’t dictate this, any more than it dictates that in an infinite number of die rolls a six must eventually come up. One possible outcome of an infinite number of die rolls is that you NEVER roll a six. Another possible outcome is that you ALWAYS roll a six. Mathematics doesn’t dictate that any particular possibility must eventually occur.

    Similarly, in a multiverse containing an infinite number of universes, there’s no guarantee of another universe identical to ours, or just like ours except one small detail, or even remotely like ours. All are possible, just like the possibility that all universes in the multiverse are empty vacuums except ours. Mathematics doesn’t dictate or favor any particular scenario.

  • Guiri

    What are these physicists smoking?

    An infinite number of universes requires that a universe must exists where an infinite number of universes does not exist.

    So which universe are we in now? the one where infinite universes exist or the one where they dont.


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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


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