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Might you be the plaything of Descartes’ evil demon?
June 25, 2013 8:41 AM   Subscribe

How You Know You Are Not a Brain In a Vat [PDF]
Abstract:A sensible epistemologist may not see how she could know that she is not a Brain In a Vat (BIV); but she doesn’t panic. She endorses her empirical beliefs, and as coherence requires, believes that she is not a BIV. (She does not inferentially base her belief that she is not a BIV on her empirical knowledge—she rejects that ‘Moorean’ response to skepticism.) I propose that she thereby knows that she is not a BIV. I flesh out the proposal, drawing on the empirical literature on metacognition, and explain why it satisfactorily resolves the skeptical puzzle.


More on BIV: Wikipedia, Philosophy Index, Stephen Hawking is 'brain in a vat',
posted by not_the_water (104 comments total) 17 users marked this as a favorite

 
Also potentially eponysterical.
posted by gimonca at 8:45 AM on June 25, 2013


I'm pretty sure I am a Brain in Some Fat.
posted by srboisvert at 8:50 AM on June 25, 2013 [9 favorites]


I am happily a Brain in a Vat.

Blub.
posted by strixus at 8:52 AM on June 25, 2013 [1 favorite]


The premise seems flawed, if I understand it correctly. "You do not freak out about the possibility of being a brain-in-a-vat. Therefore you are not a BIV."

Whut?
posted by ymgve at 8:53 AM on June 25, 2013 [3 favorites]


The premise seems flawed, if I understand it correctly. "You do not freak out about the possibility of being a brain-in-a-vat. Therefore you are not a BIV."

That's actually not as ridiculous as it seems at first. All the BIVs I've set up go stark raving mad in a remarkably short period of time.
posted by FatherDagon at 9:00 AM on June 25, 2013 [22 favorites]


Can I be a Brain in a Vat 69?
posted by ubiquity at 9:04 AM on June 25, 2013 [1 favorite]


Wow. What a massive exercise in question-begging. "Let's start from the premise that anyone who thinks this might be possible is a nutcase; now, you're not a nutcase are you? Good!"

The whole point about the hypothetical postulation of the "brain in a vat" scenario is that it would be subjectively indistinguishable from a world lived as we think we live it. Appealing, then, to how we "feel" about our subjective experiences to disprove the possibility of the hypothesis is just hilariously stupid.
posted by yoink at 9:05 AM on June 25, 2013 [19 favorites]


Five thousand quatloos says I'm not a brain in a vat.
posted by TheWhiteSkull at 9:05 AM on June 25, 2013 [7 favorites]


The key to a Brain in a Vat not going completely insane is the love of a good gorilla with a beret and French accent.
posted by robocop is bleeding at 9:05 AM on June 25, 2013 [12 favorites]


This essay is ridiculously bad, but at least I know I can take comfort of looking cool as hell in my vat, with sweet sunglasses sitting on my frontal lobe and a little umbrella stickin' out the side of the vat.
posted by Greg Nog at 9:07 AM on June 25, 2013 [5 favorites]


All I want is for someone to change my neck juice every once in a while.
posted by The Whelk at 9:11 AM on June 25, 2013 [6 favorites]


1: pour some fluid in a vat
2: put your brain in that vat
3: try not to overthink that
Ooh, I'm a brain in a vat, I'm a brain in a vat girl
posted by Metroid Baby at 9:12 AM on June 25, 2013 [7 favorites]


Has anyone else here tried Occult Chronicles, the new game by Vic Davis? In my most recent game my investigator managed to save a brain that was being transferred into a vat by the Teslarati. The brain and I chatted a bit through its interface, and it agreed to tag along and help me if I transferred it to one of the spider bot chassis. We had such adventures together. Sadly, after that I got overconfident and decided to sit down to play game of chess against Death. That was as dumb as it sounds.


Oh, and on a quick reading this article seems terrible.
posted by Balna Watya at 9:12 AM on June 25, 2013 [2 favorites]


I'm a brain in a vat...

...a vat of awesome.
posted by R. Schlock at 9:14 AM on June 25, 2013 [2 favorites]


That's actually not as ridiculous as it seems at first. All the BIVs I've set up go stark raving mad in a remarkably short period of time.

FatherDagon, this is because you have not properly studied Mi-Go surgical techniques. All that is required for indefinite metal stability is just a few... precise... excisions... and all is well!

Why I have been stored in an imperishable cylinder for decades with no ill effects!

And to think I hesitated!
posted by GenjiandProust at 9:17 AM on June 25, 2013 [4 favorites]


Brain in a Vat: an independent musician producing ambient electronica, techno and dance.
posted by not_the_water at 9:19 AM on June 25, 2013


Schrodinger's Vat: The BIV both does and does not exist.
posted by jimmythefish at 9:19 AM on June 25, 2013 [1 favorite]


Haven't read the whole bit yet, so maybe I'm repeating something he says there, but it seems that if being a BIV is subjectively indistinguishable in every way from living in a physical world as we understand it, then what's the point of proposing it? The only reason it would matter that we're living in a simulation is if it were somehow different from the real world and we could perceive that difference. If there's no possible perceivable difference, then there's no reason to suspect that this much more complicated explanation is true.

Not to turn it into a religious debate, but there are a number of people who believe in a god that's very indistinct, more of a concept than anything else, and one that doesn't interact directly in our lives. That's fine, if you want to believe that, but it's functionally no different from being an atheist.

Or, on a personal-interaction level: suppose someone you're close to is acting like a jerk to you. Are they a jerk? If we're invested in the relationship, we might make excuses for them: "He's not really a jerk, he just acts like that sometimes when he's tired or defensive or caught off-guard." But at some point you have to step back and ask yourself, what's the difference between the way this person acts and the way a jerk would act? Sometimes you find there's no functional difference, and you've been preventing yourself from acknowledging that this person is kind of a jerk. You can also turn this process on yourself; we all like to make excuses about how we're actually nice people, it's just that this one time etc. etc.

There are lots more examples where people try to make a distinction without a difference. If there's no functional difference, there's no reason to act like there's some other imperceptible but important difference. If there is a functional difference and you can clarify what it is and how to find it, great! That advances human knowledge. Otherwise, it's just muddying the waters.

In summary, if it looks like a duck, and it walks like a duck, and it quacks like a duck...
posted by echo target at 9:20 AM on June 25, 2013 [7 favorites]


I suspect some are veins in a brat.
posted by eriko at 9:21 AM on June 25, 2013 [2 favorites]


The entire premise seems fairly meaningless to me because SO WHAT if we were all brains in vats. How would having a definitive yes or no answer to this question change anything? IT WOULD NOT. Life would go on, we would still have cupcakes and puppies and supermooms and those weird tubes of water that amusingly slip out of your hands when you squeeze them and that one episode of Tom and Jerry where they take the refrigerator element out of the box and freeze over the whole kitchen and do Ice Capades.

i don't feel like reading this pdf is what i am saying basically
posted by elizardbits at 9:22 AM on June 25, 2013 [4 favorites]


i don't feel like reading this pdf is what i am saying basically

You may be functionally indistinguishable from people who have....
posted by GenjiandProust at 9:24 AM on June 25, 2013 [2 favorites]


Isn't computational irreducibility a more effective angle on this problem? Being trapped in a simulation invalidates empirical observation but it doesn't invalidate Math. Simulating the universe in exacting, consistent detail, from which further details can be inferred, is so computationally hard (see: the Halting Problem) that the only may around it is to invoke magic, or the infinities of omnipotence (which is why the Evil Demon, or more precisely, Evil Deity, is a better "pure case" than a mad scientist). Since it can be shown that being embedded in a simulation is not computationally feasible without magic, one need only apply Occam's razor to then rule out magic.

It's almost as thought philosophers don't see the connection between Gödel and Turing.
posted by belarius at 9:26 AM on June 25, 2013 [2 favorites]


I think the BIV thing is a problem philosophers like to pick at because the whole premise of philosophy is "using only the powers of my mind, I can figure out what's true about the world and what isn't". If you can't even say for sure that you're not a brain in a goddamn vat, why should one rely on the chain of reasoning that got you to existentialism or utilitarianism or what have you?

The practical answer to both these questions is that you can't and you shouldn't, probably. But you try telling that to philosophers.
posted by Diablevert at 9:29 AM on June 25, 2013 [1 favorite]


If there's no possible perceivable difference, then there's no reason to suspect that this much more complicated explanation is true.

Because if you ARE a brain in a vat, or a simulation, there is hope that the person (entity, intelligence, virus, programming error, etc) in charge of it might give things a stir, and make you immortal, or whatever, or invisible, or win the lottery. If this is really real, then this is all we get. 'This' is pretty good, an additional helping would be great.

I just realised that apparently I think the chances of organically winning Powerball are slimmer than the chances of this all being a simulation in which an overseer decides to fix the Powerball so that I win. Huh.
posted by dirtdirt at 9:30 AM on June 25, 2013 [1 favorite]


The entire premise seems fairly meaningless to me because SO WHAT if we were all brains in vats. How would having a definitive yes or no answer to this question change anything? IT WOULD NOT. Life would go on, we would still have cupcakes and puppies and supermooms and those weird tubes of water that amusingly slip out of your hands when you squeeze them and that one episode of Tom and Jerry where they take the refrigerator element out of the box and freeze over the whole kitchen and do Ice Capades.

It's like Conan the Barbarian said:

Let me live deep while I live; let me know the rich juices of red meat and stinging wine on my palate, the hot embrace of white arms, the mad exultation of battle when the blue blades flame and crimson, and I am content. Let teachers and priests and philosophers brood over questions of reality and illusion. I know this: if life is illusion, then I am no less an illusion, and being thus, the illusion is real to me. I live, I burn with life, I love, I slay, and am content."

(Really, it's from Queen of the Black Coast)
posted by zabuni at 9:33 AM on June 25, 2013 [11 favorites]


yes i too revel in the destruction of my enemies
posted by elizardbits at 9:34 AM on June 25, 2013 [4 favorites]


No, I'm not a brain in a vat. I'm a philosophical zombie—a mindless automaton that only appears to be conscious and sentient. Get it straight.

The paper seems to confuse "I am not a brain in a vat" with "It is utterly inconsequential whether I am a brain in a vat". Whether a statement is interesting has no bearing on its truth. See also: Russell's teapot, math.

Also, "suspending judgement" is not the same as "freaking out". Seriously, dude, come on.
posted by erniepan at 9:34 AM on June 25, 2013


I found the beginning of his argument rests on shaky grounds. He seems to go:

A. People who cannot leave their homes because they continually doubt their memories of turning off the stove suffer from a pathological condition called OCD.

B. Continuously wondering if you are a Brain in a Vat is like the situation in A.

C. Therefore suspecting you may be a Brain in a Vat is a pathological condition.

D. Since you do not have a pathological condition, you are not a Brain in a Vat.

Which ignores that situation A is really only pathological if first, it interferes with the life you would prefer to live, and second, you have not left the stove on. If you have left the stove on, this is not pathology but prudence. So worrying about being a Brain in a Vat is justified if you are, in fact, a Brain in a Vat. We are back at the start.

Diablevert, I think you miss the point of the exercise -- while some philosophers have pursued examination of the physical world through thought alone (if I recall correctly, Aristotle was criticized for actually doing experiments (albeit in a haphazard way)) -- I think the point of the Brain in a Vat discussion is -- if I were a Brain in a Vat, what experiments could I run to prove I am/am not? If we can't imagine such an experiment (whether it can be actually run or not*), the question is resolvable.

*Thus the idea of a thought experiment -- Schrödinger did not actually kill a bunch of cats or even half-cats.
posted by GenjiandProust at 9:37 AM on June 25, 2013


computational irreducibility

Ah, but there's no reason to think the simulation has to run in real time. Maybe one Planck time in the simulated universe takes eons to calculate in the real universe, but as long as the calculation is correct and each step proceeds smoothly from the previous, you'd never notice from inside.
posted by echo target at 9:37 AM on June 25, 2013 [4 favorites]


The entire premise seems fairly meaningless to me because SO WHAT if we were all brains in vats. How would having a definitive yes or no answer to this question change anything?

If you knew definitively that you're a brain in a vat, couldn't you go around killing people indiscriminately and feel no remorse because they're not real?
posted by ultraviolet catastrophe at 9:38 AM on June 25, 2013


The entire premise seems fairly meaningless to me because SO WHAT if we were all brains in vats.

No, the premise is that I'm a brain in a vat and that none of the rest of you actually exist at all. And so my moral duties to you are the same as my moral duties to NPCs in a video game.

Isn't computational irreducibility a more effective angle on this problem? Being trapped in a simulation invalidates empirical observation but it doesn't invalidate Math. Simulating the universe in exacting, consistent detail, from which further details can be inferred, is so computationally hard (see: the Halting Problem) that the only may around it is to invoke magic, or the infinities of omnipotence (which is why the Evil Demon, or more precisely, Evil Deity, is a better "pure case" than a mad scientist). Since it can be shown that being embedded in a simulation is not computationally feasible without magic, one need only apply Occam's razor to then rule out magic.

No, the simulation just cheats so that I'm convinced the universe is simulated in exact detail. And it probably doesn't have to cheat very hard, because, if cognitive studies are to be believed, brains like mine are all too ready to do a half-assed job of gathering incoming sensory data and just extrapolating the rest.
posted by straight at 9:41 AM on June 25, 2013 [2 favorites]


Being trapped in a simulation invalidates empirical observation but it doesn't invalidate Math. Simulating the universe in exacting, consistent detail, from which further details can be inferred, is so computationally hard (see: the Halting Problem) that the only may around it is to invoke magic...Since it can be shown that being embedded in a simulation is not computationally feasible without magic, one need only apply Occam's razor to then rule out magic.

I dunno, isn't my brain doing this already? Like, my conscious experience of the universe already relies on a bunch of shorthand, algorithmic model, patches and jerry-rigs. In order for me to be a brain in a vat, I don't know that what's necessary is for the Experimenter to simulate The Universe. Just enough so that it feels like a universe to me. The stars can be a a set of fairy lights on velvet, metaphorically speaking. Set dressing.
posted by Diablevert at 9:41 AM on June 25, 2013 [1 favorite]


(Nice try, simulation, undermining my doubts with that ultraviolet catastrophe comment slipping in right before mine.)
posted by straight at 9:42 AM on June 25, 2013


(And, wow, Diablevert, too. Not very subtle, simulation.)
posted by straight at 9:42 AM on June 25, 2013 [1 favorite]


Is it well understood what is meant by "Brain in a Vat"? Because the author didn't seem to clearly define this.

If BIV means, literally a human brain floating in a vat, to the extent that reasonable follow up questions might be, "What is the vat made of? Is it kind of steampunkish with steel and rivets? Is the liquid clear or opaque?" If so, then I'd agree, no, no one actually thinks they might be a brain in a vat.

On the other hand, if BIV is shorthand for there exists higher orders of reality to which we do not have direct experimental access, I think most physicists would probably say, yes, we're brains in vats.

There are various interpretations of the phrase I can think of that would fall between those two and it's not at all clear to me what is actually meant.
posted by justkevin at 9:44 AM on June 25, 2013 [2 favorites]


Greg Nog: "This essay is ridiculously bad, but at least I know I can take comfort of looking cool as hell in my vat, with sweet sunglasses sitting on my frontal lobe and a little umbrella stickin' out the side of the vat."

Greg Nog: The Spuds Mackenzie of Brains in Vats
posted by MCMikeNamara at 9:46 AM on June 25, 2013 [2 favorites]


couldn't you go around killing people indiscriminately and feel no remorse because they're not real?

I could do that already if it wasn't for that pesky social contract thing.
posted by elizardbits at 9:47 AM on June 25, 2013 [2 favorites]


Saying the universe can't be a simulation because it would be computationally hard is like saying Minecraft can't be a game because creating logic circuits with Redstone is hard and slow.

You can't assume anything about computational capabilities of something that is outside of our (possibly) simulated universe.
posted by ymgve at 9:49 AM on June 25, 2013 [12 favorites]


Haven't read the whole bit yet, so maybe I'm repeating something he says there, but it seems that if being a BIV is subjectively indistinguishable in every way from living in a physical world as we understand it, then what's the point of proposing it?

Well, the truth of the matter isn't really the central concern with such a thought experiment since, like you say, it's effectively unreachable. It's really more useful as a framing of the formally unbridgeable gap between reality and our perception of it.

Arguing about its plausibility makes about as much sense as arguing whether a man would really sit in a room for long enough to algorithmically translate a conversation into Chinese by hand.
posted by invitapriore at 9:51 AM on June 25, 2013


Zabuni, I'm just getting into the Robert E. Howard Conan stories. Is that one of his?
posted by Mister_A at 9:52 AM on June 25, 2013


elizardbits just made a telling slip: See, outside the vats, we have no supermooms.
posted by sandettie light vessel automatic at 9:53 AM on June 25, 2013


On BIV crime sprees: What about being a BIV would prevent your being thrown in sim-universe jail for doing that? What possible hope do you have of escaping the simulated world that you would mess up the rest of your sim-life with the sim-world consequences of that spree?
posted by gubo at 9:58 AM on June 25, 2013 [1 favorite]


I just realised that apparently I think the chances of organically winning Powerball are slimmer than the chances of this all being a simulation in which an overseer decides to fix the Powerball so that I win.

Hence, prayer.

Those prophets wandering around in deserts weren't as dumb as you think.
posted by Tell Me No Lies at 9:59 AM on June 25, 2013


But I am a brain in a vat, and so are you.
posted by seanmpuckett at 9:59 AM on June 25, 2013


Forget Brain in a Vat, Boltzmann Brains are where it's at!

If our current level of organization, having many self-aware entities, is a result of a random fluctuation, it is much less likely than a level of organization which only creates stand-alone self-aware entities. For every universe with the level of organization we see, there should be an enormous number of lone Boltzmann brains floating around in unorganized environments. In an infinite universe, the number of self-aware brains that spontaneously randomly form out of the chaos, complete with false memories of a life like ours, should vastly outnumber the real brains evolved from an inconceivably rare local fluctuation the size of the observable universe.
posted by leotrotsky at 10:02 AM on June 25, 2013 [3 favorites]


Flapjax and I have an unrecorded song called BRAIN IN A VAT -- he wrote the lyrics and I wrote the music. Wonder where it is?
posted by unSane at 10:02 AM on June 25, 2013 [1 favorite]


The thing is, you need to be ready if somebody offers you a red pill.

BRB...I'm going to see the turtles now.
posted by mule98J at 10:03 AM on June 25, 2013


It's really more useful as a framing of the formally unbridgeable gap between reality and our perception of it.

Thanks, that makes sense. Would it be correct, then, to say that since we can't convincingly disprove the BIV theory, it's not possible to do any philosophy based on nothing but logic and direct perception? That all philosophy necessarily has to start with a set of fundamentally unprovable assumptions, even if we keep them to a minimum?
posted by echo target at 10:03 AM on June 25, 2013


Maybe one Planck time in the simulated universe takes eons to calculate in the real universe, but as long as the calculation is correct and each step proceeds smoothly from the previous, you'd never notice from inside.

In other words, "assuming infinite time and/or infinite space and/or infinite energy..."

I prefer not to assume infinities, of any kind. Infinities might exist, but I see no reason why not to remain strictly agnostic about them and operate without assuming them. That leaves us with two hypotheses, one of which requires incalculably more entropy than the other. Minimize your marginal likelihood and call me in the morning.
posted by belarius at 10:03 AM on June 25, 2013


FatherDagon, this is because you have not properly studied Mi-Go surgical techniques.

::raises eyebrow-equivalent ridge of pulsing gelatinous demi-flesh::

Wait, the Mi-Go think the goal should be *preserving* sanity? I think they may not have studied MY techniques well enough.
posted by FatherDagon at 10:05 AM on June 25, 2013 [2 favorites]


Metafilter: Such a person is not to be persuaded by argument; they are to be treated in the same way as a patient with OCD—medically.
posted by b1tr0t at 10:05 AM on June 25, 2013 [1 favorite]


Could my brain be subject to a value-added tax?
posted by Mental Wimp at 10:06 AM on June 25, 2013 [3 favorites]


Just remember this, my friends: I am the sexiest brain in a vat ever!
posted by Mister_A at 10:07 AM on June 25, 2013


no that would be vat on a brain, not brain in a vat

besides, who's to say that our brains aren't in game cartridges or cell phones? - why does it always have to be a vat?
posted by pyramid termite at 10:08 AM on June 25, 2013 [3 favorites]


Anyway, if I'm just a brain in a vat, how come it's so hot in the vat today? BURN!!!!! VAT BUUUUUUURRRRRN!!!!!
posted by Mister_A at 10:08 AM on June 25, 2013


also, would that make me a vateran?
posted by pyramid termite at 10:09 AM on June 25, 2013


And if you're ill you will be visited by a Vaterinarian.
posted by Mister_A at 10:10 AM on June 25, 2013


And if a drunken entity of some sort kicks over your vat, it's a vatastrophe!
posted by Mister_A at 10:10 AM on June 25, 2013


and if you become pope you live in the vatican

oh, wait ...
posted by pyramid termite at 10:11 AM on June 25, 2013 [1 favorite]


And if you use an apostrophe on a simple (non-possessive) plural, you're stupid!
posted by Mister_A at 10:11 AM on June 25, 2013


and if you don't know the difference between a plural and a contraction you'll never make vatedictorian
posted by pyramid termite at 10:13 AM on June 25, 2013 [2 favorites]


It's funny how you put 'vat' in there!
posted by Mister_A at 10:14 AM on June 25, 2013


In other words, "assuming infinite time and/or infinite space and/or infinite energy..."

Not at all. If you assume the universe is finite (it is, as far as we can tell), then you can fully simulate it using finite time, matter, and energy. You'd need an extremely large amount of all of them, but you wouldn't need magic. Theoretically you could do it with any Turing-complete computer, given enough time.

I'm not saying it's a convincing argument; obviously it's silly to assume we're part of a huge simulation that coincidentally looks exactly like physical reality. I'm just saying you can't refute it by saying it's computationally impossible.
posted by echo target at 10:14 AM on June 25, 2013


i'm going to make like porky pig and say "vat's all folks"
posted by pyramid termite at 10:15 AM on June 25, 2013 [2 favorites]


Wait, the Mi-Go think the goal should be *preserving* sanity? I think they may not have studied MY techniques well enough.

There are a variety of sanity thresholds, depending on your desired "signal to gibbering" ratio. Serious experimenters need to plan for this in advance, or the costs of obtaining materials becomes prohibitive. Plus, using one's nippers for emotional manipulation is just darned fun!

Also "eyebrow-equivalent ridge of pulsing gelatinous demi-flesh" is officially my favorite body part. I long for a conversation into which I can slip that phrase!
"
posted by GenjiandProust at 10:15 AM on June 25, 2013 [2 favorites]


From the draft article linked: "We all take it as settled that one is not a BIV, that one has reliable perceptual faculties, and so on."

Ha. No. That's the entire point.

We actually do act like we're a BIV, because the answer to "BIV or No?" makes no difference.

We don't go on killing sprees, etc. because there are consequences. The consequences are as real as our existence.
posted by mountmccabe at 10:21 AM on June 25, 2013


What a massive exercise in question-begging...Appealing...to how we "feel" about our subjective experiences to disprove the possibility of the hypothesis is just hilariously stupid.

To be fair, on first skim the paper's argumentative structure seems to be:

1. Here's a fairly uncontroversial account of how various beliefs count as a certain kind of knowledge ("consort knowledge", p. 14).
2. The way in which we believe we're not BIVs counts as an instance of that kind of knowledge.
3. So we know we're not BIVs.

The account mentioned in #1 is not a foundationalist account of knowledge. Any argument against the skeptic that departs from foundationalism will probably seem question-begging to a foundationalist. But then foundationalism's descent into skepticism will seem like its own reductio, to a non-foundationalist.
posted by Beardman at 10:21 AM on June 25, 2013 [3 favorites]


To echo ymgve above, any objections to the BIV theory based on "it'd be too hard" or "computers aren't that advanced" or whatever can be countered with the argument that perhaps what we would be outside of the vat is not remotely human at all, and that reality outside of the simulation is nothing like we think it is.

Perhaps the world as we know it is a piss-poor simulation of reality that our True Senses would perceive if we weren't plugged into the Matrix here. Five senses? Or twenty? Ha! We have nine thousand and six, but this chintzy program we're in can only handle a few. And the detail here is lousy; my True Eyes, like those of the mantis shrimp, can see millions of colors that this simulation can't even pretend exist.

Now that I'm reliving sophomore year of college with this line of thought, pass the malt liquor and turn on the Soundgarden CD.
posted by Harvey Jerkwater at 10:22 AM on June 25, 2013 [1 favorite]


Obligatory Roald Dahl. Hell is other people outside the vat.
posted by Mchelly at 10:24 AM on June 25, 2013 [1 favorite]


Would it be correct, then, to say that since we can't convincingly disprove the BIV theory, it's not possible to do any philosophy based on nothing but logic and direct perception? That all philosophy necessarily has to start with a set of fundamentally unprovable assumptions, even if we keep them to a minimum?

This is a surprisingly complicated line of inquiry! I like the Stanford Encyclopedia's article on Rationalism vs. Empiricism as a good overview of the problem.
posted by invitapriore at 10:25 AM on June 25, 2013


Now that I'm reliving sophomore year of college with this line of thought, pass the malt liquor and turn on the Soundgarden CD.

Entertainment Weekly called Superunknown "a boiling vat of volcanic power."
posted by Beardman at 10:27 AM on June 25, 2013


Can someone just post the goddamn Monty Python philosopher's song and close the thread?
posted by thelonius at 10:29 AM on June 25, 2013


But we "are" brains in a vat a skull shaped vat... RAD!
posted by mrgroweler at 10:32 AM on June 25, 2013


Also! It's worth noting that Descartes' evil genius is actually a more skeptical take on this problem than the brain in the vat as generally understood, since he posits that the evil genius also has control over what we take to be a priori knowledge, such that for instance we may be misled as to whether the angles that comprise a triangle do actually sum to 180°.
posted by invitapriore at 10:33 AM on June 25, 2013


This line of inquiry won't get you very far.


A. People who cannot leave their homes because they continually doubt their memories of turning off the stove suffer from a pathological condition called OCD.

B. Continuously wondering if you are a Brain in a Vat is like the situation in A.


Dammit, that reminds me I left the burner on under the brain in a vat.
Oh well, stew tonight!
posted by BlueHorse at 10:36 AM on June 25, 2013 [2 favorites]


Always loved Alpha Centauri's Brain-in-a-Vat sequence for the Bioenhancment Center:

We are all aware that the senses can be deceived, the eyes fooled. But how can we be sure our senses are not being deceived at any particular time, or even all the time? Might I just be a brain in a tank somewhere, tricked all my life into believing in the events of this world by some insane computer? And does my life gain or lose meaning based on my reaction to such solipsism?

Project PYRRHO, Specimen 46, Vat 7
Activity Recorded M.Y. 2302.22467
TERMINATION OF SPECIMEN ADVISED

posted by Tabs at 10:39 AM on June 25, 2013 [2 favorites]


The article on epistemology in general also has a good discussion of the BIV problem.
posted by invitapriore at 10:40 AM on June 25, 2013


Just reading the first 3 pages of that reminded me why I quit being a Phil major.
posted by Aizkolari at 10:40 AM on June 25, 2013


On BIV crime sprees: What about being a BIV would prevent your being thrown in sim-universe jail for doing that? What possible hope do you have of escaping the simulated world that you would mess up the rest of your sim-life with the sim-world consequences of that spree?

That's just pragmatism, not morality. The moral question is, if I were convinced that everyone else was a simulated NPC in my own private video game, what would I do whenever I had the chance to get away with it?
posted by straight at 10:55 AM on June 25, 2013


My experience with roguelikes tells me that if everyone else was a simulated NPC in my own private video game, I would live very, very carefully.
posted by ymgve at 10:57 AM on June 25, 2013 [2 favorites]


What kind of simulated game? Is it a FPS or action/adventure/exploration or RPG or what? Is it the Littlest Pet Shop game?
posted by Mister_A at 11:04 AM on June 25, 2013


[Descartes] posits that the evil genius also has control over what we take to be a priori knowledge

IIRC there is some controversy over this - doesn't he sort of propose this in one place, and reject it in another? If the evil demon casts doubt on the laws of logic, then his escape from skepticism -- which relies on logic -- won't work.
posted by LobsterMitten at 11:05 AM on June 25, 2013


...adding a woeful epicycle to the Cartesian Circle.
posted by Beardman at 11:09 AM on June 25, 2013 [1 favorite]


for instance we may be misled as to whether the angles that comprise a triangle do actually sum to 180°.

We are. In school we're told that the angles of a triangle sum to 180°, but Earth is better modeled by an elliptical geometry, so the angles of a triangle actually all sum to greater than 180°*, unless we look only locally and do something like bend out paper into a hyperbolic geometry, in which case the angles of a triangle in that mini-universe (which is the paper, not the earth) sum to less than 180°. Also, IIRC, there is some debate about what the geometry of the universe as a whole is (sorry, not a physicist), but until we nail that down we actually don't know what the sum of the angles of a triangle is.

also, triangles don't really exist, so there's that problem with summing the angles, too.

*try it yourself. You can draw a triangle from north pole to a point on the equator to a quarter of the way around the equator and back to the north pole and get a triangle of approximately 270°.
posted by yeolcoatl at 11:37 AM on June 25, 2013 [2 favorites]


I'm the goddamn Vatman.
posted by MrBadExample at 11:39 AM on June 25, 2013 [3 favorites]


IIRC there is some controversy over this - doesn't he sort of propose this in one place, and reject it in another? If the evil demon casts doubt on the laws of logic, then his escape from skepticism -- which relies on logic -- won't work.

As I remember it, he solves this problem by appealing to a benevolent God to eliminate the possibility of us being deceived in the first place, basically, but it's been a good while.
posted by invitapriore at 11:43 AM on June 25, 2013


Despite all my brains, I am still just a vat on the stage.
posted by mmrtnt at 11:50 AM on June 25, 2013 [4 favorites]


Calling Dr Hfuhruhurr....
posted by OHenryPacey at 12:04 PM on June 25, 2013


Hey. Does this vat make my brain look fat?

posted by mmrtnt at 12:13 PM on June 25, 2013


This discussion reminds me of Ted Bundy's defense of solipsism. Make of that comparison what you will.

My main problem with solipsism is that it's boring. Also: "Cogito ergo sum," implies the existence of at least two Turing-test capable intelligences. It proves that *I* exist, but it also implies that something other than *I* exists. That is to say, there's the thing that I need the word "I" for to differentiate myself from in the first place. And that something other, from empirical observation, is able to trick me into believing that parts of it are sentient, therefore it must be sentient for all functional purposes also.

We're left with the other big questions, then, like, how is that second intelligence divided? Is it one entity playing a trick on me? Is it divided amongst billions of humans and some really smart animals as it appears to be? Is it divided between things that are being-in-itself and things that are being-for-itself? That is to say, is a rock different than a man or are they made of the same stuff? Is that same stuff mechanical or made of Platonic ideals, essence or thought? What happened to Wesley Crusher after the Traveller's training? Where is Benjamin Sisko? Who is the Dreamer, who is the Architect and does that damn top ever stop spinning? What's at the top of the Dark Tower? What is the question with the answer 42?
posted by Skwirl at 12:16 PM on June 25, 2013


Anyone else hungry for ramen?
posted by Divine_Wino at 12:34 PM on June 25, 2013


Ich bin ein Braininvat.
posted by Kabanos at 12:51 PM on June 25, 2013 [1 favorite]


I have images relevant to this thread.

posted by mmrtnt at 12:57 PM on June 25, 2013


Obviously it's silly to assume we're part of a huge simulation that coincidentally looks exactly like physical reality.

What exactly does physical reality look like?

When I go outside, I think that it doesn't look like the earth is going round the sun. Rather, it looks like the earth isn't moving at all. But then ... that's not right. In fact, it looks exactly the way it would look if the earth were moving. It has to, since the earth actually is moving.

If we are part of a simulation, then we don't really know what physical reality -- as distinct from the presentations of the simulation -- looks like. So, we are left with something rather different: if we are in a huge simulation, then the simulation coincidentally looks exactly the way a huge simulation would look. Shocking.

It seems to me that the hypothesis that we are in a simulation is verifiable but not falsifiable. Assuming that it is possible for you one day to be shown that you were in a simulation the whole time -- say by God or the Almighty Programmer or what have you. On the other hand, the hypothesis that we are not in a simulation is falsifiable but not verifiable. Consequences for philosophy of science follow.
posted by Jonathan Livengood at 1:18 PM on June 25, 2013 [5 favorites]


tangentially: I confess I never understood descartes' argument against the existence of the evil genius. but then I also concluded pretty quickly that descartes was a wanker, so I may not have been taking him seriously enough....
posted by lodurr at 1:52 PM on June 25, 2013


I like these kinds of topics, but the article has a couple of logical gaps in the very first page.
posted by polymodus at 2:02 PM on June 25, 2013


Nick Bostrom's Are You Living In a Computer Simluation? is the canonical paper proposing that it is plausible that we are all being simulated. You may think it's crazy, but it is at least entertaining to go through the argument and try to find the place where you disagree with the logic. At least read the abstract, which summarizes the argument in one sentence.
posted by dfan at 2:29 PM on June 25, 2013 [2 favorites]


Lodurr: don't feel bad, the second half of the book (where Descartes recreates the world) is logically terrible in general.
posted by jaduncan at 2:31 PM on June 25, 2013 [1 favorite]


If we can't imagine such an experiment (whether it can be actually run or not*), the question is resolvable.

Unless you meant to type "can" instead of "can't" I am very confused. Surely if someone wrote a version of this paper that was actually correct --- a method whereby through reason alone we could determine that we are not brains in vats --- wouldn't that be a bit like the philosophy version of solving Fermet's Last Theorum?
posted by Diablevert at 3:10 PM on June 25, 2013


SO WHAT if we were all brains in vats.

because there might be cheat codes. If we knew we were brains in vats, maybe we could use that info to level up.

Maybe eye of newt, and toe of frog,
Wool of bat, tongue of dog, and Rhino horn are system exploits

We could stop trying to explain the logic of quantum physics,
"oh that's just how the code works, it's mostly just quantizing and aliasing, black holes are just arithmetic overflow"

We can start looking for a command line interface, for the system calls to build new planets and tunnel to other universes.
posted by compound eye at 3:27 PM on June 25, 2013 [1 favorite]


Like many people, I think Descartes cheats us massively, with a circular argument guaranteeing his clear and distinct ideas. Also, couldn't the evil demon make him think that things are clear and distinct, when they are not? One critic said he can't even say "I think...", because he is awarding himself a metaphysically unitary self out of nowhere. And so on.

But he is an amazing thinker, a true genius, and I think he tried as hard and as well as anybody has to put across very abstract speculations in a way that any intelligent reader can follow. Anyway, he let the cat out of the bag: once you start thinking in terms of your notion of the real as actually a representation that you generate, in however obscure a way, it is quite difficult indeed to dispel the problems that come up, and you are off to the next couple of hundred years of Western philosophy.
posted by thelonius at 6:06 PM on June 25, 2013


The worst thing about being a BIV is that you would feel so alone. You know, without all your vatos around
posted by whir at 11:55 AM on June 26, 2013 [1 favorite]


belarius: Maybe one Planck time in the simulated universe takes eons to calculate in the real universe, but as long as the calculation is correct and each step proceeds smoothly from the previous, you'd never notice from inside.

In other words, "assuming infinite time and/or infinite space and/or infinite energy..."

I prefer not to assume infinities, of any kind. Infinities might exist, but I see no reason why not to remain strictly agnostic about them and operate without assuming them. That leaves us with two hypotheses, one of which requires incalculably more entropy than the other. Minimize your marginal likelihood and call me in the morning.
There's no assumption of infinities being made. Large, real numbers like 1 eon / 1 Planck time are not infinite.
posted by IAmBroom at 1:14 PM on June 26, 2013 [3 favorites]


I have been on a kick reading the OUP "Very Short Introduction" series lately. So I read the title on "Reality", which had some interesting discussion of Bostrom's simulation arguments.

Get this -this is great - for the sake of argument, grant enough computing power to somehow run a sub-atomic level simulation. (Maybe you can cheat and only simulate at that level when you have to, like to keep the CERN part of the simulation going). OK, this is a huge, but limited amount of computing capability. Now, run your sim. What happens if the beings in your simulated world themselves decide to start experimenting with simulations? Then you'll need a lot more computing power, to provide to them. Now this might propagate down a stack of simulations for a while, but, eventually, you will hit the wall, and the whole pile of universes collapses. So, it may be very dangerous to start trying to build these things, since we could be near the limit of computing power (which has to come from the "real" universe, wherever that is, in this argument, I guess).

Bostrom has, I think, published papers trying to establish that there could theoretically be enough computer to simulate a world. But what do you do with the heat that bad boy would put out? I don't buy it for a second, no sir - *kicks stone*.
posted by thelonius at 5:56 PM on June 28, 2013 [1 favorite]


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