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Rene Descartes

Weird Science: Testing Brains in Vats


I don’t know how seriously other scientists will take this, but according to this article at, physicists at the University of Bonn believe they can develop a test that will accurately measure whether or not we are a bunch of brains in a vat. Or just one one brain in a vat. The test would depend upon our understanding of something called quantum chromodynamics, a field of study concerned with the way elementary particles are bound together by different forces.

Anyone with a thorough understanding of high energy physics can check the paper out on the arXiv website. If you can make anything of it, please don’t be afraid to leave a comment. In the meantime, I have to wonder at the idea that this is testable at all. As the article notes,

… any conclusions resulting from such work would be limited by the possibility that everything we think we understand about quantum chromodynamics, or simulations for that matter, could be flawed.

The data this test would return would have to be checked against a simulation, unless I’m missing an important fact and there’s something else to check the data against. If that’s the case, we run into the same problem everybody else has run into when pondering this question: how do I know my experiences or my data adequately represent whatever “reality” is “out there?” And if the answer is something like “we have mathematical models that tells us what we should find,” how do we test whether those mathematical models are accurate or reliable?

If all I’ve experienced is this thing that we’re calling a simulation, what can I know about an existence that isn’t a simulation? These are pretty elementary philosophical questions—but none of them have been answered, which is why this article had me raising my eyebrows.

The conceptual setup here is another reason I’m skeptical. It’s not that I don’t understand the concepts (I think I do to a small degree), it’s that I don’t think they’re very clear. That may be the article’s fault more than the scientist’s, but I’m still left wondering how they’d get around some pretty fundamental problems. For instance, what are the simulations they are using simulations of? If I devise a simulation for reality that demands particular results, and then I find that those results match what I see in reality, why should I conclude that reality is a simulation? Why not conclude the opposite and say that I’ve devised a very good simulation of what’s “real?” I get the feeling a lot of this could be cleared up by someone who understands the kinds of simulations they’re talking about, but until I can get a grasp on that, I’m left to wonder.

There’s also a problem of consciousness. My existence is so caught up in the concepts of reality and simulation that I can’t imagine a way to untangle the two. What I mean is that the idea of simulation only seems meaningful from a conscious subject’s point of view. Is it possible this test somehow accounts for consciousness? Is it even possible to think about the difference between reality and simulation without a clear sense of what a conscious subject is?

I know I’m jumping all over the place, but this little article brought up all sorts of questions, and I haven’t thought about these kinds of problems in a long time. As it stands, I can’t help but be skeptical. Not about my existence, but about that test.


Author: Laughter

I like music and philosophy. And baseball.

28 thoughts on “Weird Science: Testing Brains in Vats

  1. Wow, that’s heavy. Good luck to all those who actually understand just a small piece of it.

    I do have a reasonable understanding of elementary physics. Just enough to read something like this and realize just how much I really don’t know.

    Anyway, I do use some of it in the occasional cartoon I create…………



  2. Pingback: Weird Science: Testing Brains in Vats « disabilityadjusted

  3. It’s impossible to prove that we aren’t brains in vats/ a brain in a vat. Even the results of the test would be a matter of experience and experience is something that might be an illusion, thus the results of the test might be an illusion. Interesting post though

  4. I am not good at physics though I like this post as I find these concepts quite interesting since it is twisted with philosophy as well. : ) Moreover, I have not known about the principle of a ‘brain in a vet’, so cheers for enriching my knowledge.

  5. Loved this post .

  6. Very interesting post, thanks for sharing! And congrats on being Freshly Pressed!

  7. I think we are all brain in a vat! Can’t wait to see what you post next!

  8. This is really neat. It’s not often such a philosophical post gets FP. Thanks for sharing!

  9. AFAIC, if I still have to set my alarm clock and go to work tomorrow, what the hell difference does it make if I’m a brain in a jar? I AM a brain in a jar — the jar is my skull.

    • One of the consequences of a simulated universe, or of being a brain in a vat, might be a change in our ethics, or in the way we feel about morality. If everything is an illusion or simulated, and therefore not “real,” why not act more selfishly when given the chance? Why not steal when we want something, or even kill? Our actions take on a different meaning when they don’t have any consequences grounding them. That isn’t necessarily an airtight response (Buddhists might think it’s important to act ethically even if the universe is an illusion!), but it’s one reason we might want to think about whether the universe is real or not. Thanks for reading and leaving a comment!

      • Not a persuasive argument for me, though. The assumption underlying that is that we will always want to act as poorly as we can get away with anyway. So that’s no different from what we have now in the end. In the words of Buddhist adherents, this is a question which does not edify.

      • I tend to agree with you. But I think we could come up with other scenarios that wouldn’t assume our worst qualities, and I don’t think the question is a dead end. For instance, if the universe were all just a simulation, why act at all? Why not find a nice spot under a tree and let it all pass by? I think there’s something existentially important about our decisions having some real significance. It is disturbing to think that this might all be an illusion, disturbing enough that it might call all of our actions into question, good and bad.

  10. I’ve actually been thinking about this concept for months now after rewatching Inception and, though I still believe my world to be reality, there is just no way to disprove the ‘brain in a vat’ theory inside the simulation. If someone disrupted the simulation from outside of it however, we wouldn’t know of anything other than the ‘world’ we’re used to… it’s a very intriguing idea. 🙂 Good Post!

    • “Inception” is a great reference here. One variation of the “brain in a vat” argument is the “life is a dream” argument. I think we can find our way out of this conundrum, but not by proving it in a conventional or scientific sense. Thanks for reading and leaving a comment!

  11. I really like your blog and would love you to feature on mine, All you have to do is write five suggestions along with a link back to your site. Please check out the blog and see the sort of things people have written about. Please consider following me on facebook.

  12. Cool post! I don’t understand how come there aren’t much more comments and tweets and shares! I am a theoretical chemist, which means I deal with the laws of quantum mechanics in order to describe a molecular system. I’m not a fan of extrapolating science into philosophy because more often than not this is done the wrong way!
    I say, if we are brains in a vat, then lets just enjoy it because there isn’t any warranties that we can escape pof it anyway! Congratulations on being freshly pressed!

    • I’m very interested in the places where science and philosophy meet. I’m convinced there are some questions science simply can’t answer – in fact, I wonder if it can even properly address certain questions. I hope to post more about this subject soon. Thanks for reading and leaving a comment!

  13. Wow, evidence of shared consciousness/interconnected. Thanks for post.

  14. To me it’s a high-tech version of the age-old arguments about existentialism and probably just as un-answerable. As I understand the abstract what they’re actually saying is that they started with the assumption that the universe WAS a numerical simulation, because it appears to fit the mathematics used to numerically simulate the universe… Obviously the logic is not QUITE as circular as that sounds, but the reality (heh heh) of this particular hypothesis is that it’s a logical construct derived from mathematics, not a hypothesis based on observable empirical evidence. It’s framed by the direction that a lot of the theoretical work has gone. Just like every other existential argument.

    My take? I think we shouldn’t confuse substance with the candy wrapping. The simpler explanation (Occam’s Razor) is that the observed universe is as it is….maybe… 🙂

    • Awesome. Great insight, thanks for posting that. That they assume the universe is a simulation, or even like one, is one reason I’m so skeptical about the test in the first place. I’m also aware that I know very little about mathematical simulations like this one.

      The difference between facts derived from math and facts derived from empirical observation is something I’d like to know a lot more about. One of the problems I remember studying as an undergrad in philosophy is the status of numbers: whether they’re real, universal, logical constructs, etc. It’s a problem that popped up again during my grad studies on Kant. I’d have to go back over all my notes to make sense of it all, though.

      I’m skeptical about the test, but I’m also skeptical of being too sure about anything.

  15. I tend to concur with Matthew Wright’s response. Though I (literally) once poked around in a vat of brains stored in a state psych facility. I hope I didn’t alter someones reality. ???

  16. Such an interesting idea. We discuss these issues in philosophy a lot – about whether the reality I experience here is the true reality or just a projection or some sort of trick or etc. How do you quantify experience, though? How do you test reality for reality? It is sort of absurd to think that this has been pushed into a laboratory, rather than remaining where I think it belongs – in philosophical discussion.

    • I agree, and it’s encouraging to see replies like this. Too much faith is put into science’s ability to answer all of our questions. This makes me sound irrational, but I’m only questioning the extent to which one science can answer questions about another, i.e. can physics completely describe “reality?” I hope to write on this topic more soon. Thanks for commenting!

  17. Pingback: Describing Reality: Philosophy vs. Science « Laughter

  18. Reblogged this on thewordpressghost and commented:

    Lucas asks us if physics can truly describe reality.

    It is a great question. And it is more important since a ‘science project’ is claiming they can basically read our minds. Although they note, they could be completely wrong.

    Interesting overall. Novel in several ways.



  19. It’s not so much the scientists believe we’re living in a simulation; a simulation is the only thing they can do to confirm anything in this field! The whole thing is flawed; math/logic are forms of *contained* data, competing with the empirical data that is conscious observation, the ‘createe’ looking at the created.
    The actual substance, not bounded outside its own rules, and thereby neither illusion nor artificial,
    is instead organic, fluid in its quantum physics (dare I say, spiritual); the Heisenberg principle states that these tests cannot be done without modifying the material!
    Beyond that, the experiment is useless. (In playing Devil’s Advocate,
    with the other illusory movie in two degrees of separation of Keanu Reeves, The Matrix.)
    One here already mentioned why: if the whole thing surrounding is an illusion, then the results are an illusion.  The experiment will only achieve monetary grants, while we, the people who actually use our brains in skull-vats of spinal fluid are…screwed.

    You were Freshly Pressed for getting actual science and humor to work together…plus images.
    Congrats! 🙂

  20. Pingback: Nietzsche Contra Science, Part I « Laughter

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