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Comment by throwaway_yy2Di | Hacker News Reader

Wow, what a tangle of verbosity. Yes, you could be a brain in a vat. Or you could be a brain on a biped. Obviously you cannot distinguish between these two possibilities merely by thinking about them, because your thought processes are equally compatible with either scenario (by construct, by the premise of the question). A simulation good enough to be indistinguishable from reality, cannot be distinguished from reality -- that's the definition.

The fun thing about this quack philosophy is that's it's falsifiable, that in a couple decades, we'll actually have brains in vats, and kids will play games where they shuffle a kid's brain around and have him guess if he's in a vat or not. And with the higher-end iVats, they'll never be able to tell. And they'll totally ridicule the tenured philosophy faculty, they'll be so mean, what the hell have you been doing with your grant money?

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The brain in a vat that you predict in a couple of decades could be a brain in a vat that thinks they have put a brain in a vat. This type of assumption is _not_ falsifiable (like $deity existence and so on) therefore open to speculation, based on each one their own heuristics and belief, but not rock-solid science.

I personally believe that the brain in a vat doesn't pass Occam's razor... but I have no proof.

Occams Razor is a good general rule, but you're right, not proof.

The related "This is all a simulation" argument is interesting, especially as computer power increases. If we ever get to the stage where we can simulate even a simpler sentience in a far smaller universe at a fraction of real speed then how do we know that's not exactly what's happening with us... ?

if you believe that we can reach this stage, and that we will create simulations when we do, it seems wildly implausible that we are _not_ in a simulation - because that would imply we'd be the first people anywhere, in any universe, to do such a thing.

Well yes, as a thought exercise I started idly wondering the other day how, if/when we reached the stage of development ourselves, we might go about making contact with the next layer up...

Probably make a decent sci-fi short story. Now if only I had the talent or patience for writing...

http://qntm.org/responsibility is an interesting go at it, and where I first learned of the concept. His other fiction is pretty fun, as well.

That's really quite cool. Thanks for that :)

--edit-- My own thoughts were along the lines of - humans decide we're probably in a simulation, and try to figure out how we could attempt communication with the simulators. To do so we decide to build our own simulation, then run it at double speed and watch how they try to communicate with us. Then recurse...

If you ever read a story like that, you'll know someone with the same idea but more motivation than me wrote it :)

Very nice story indeed :D In the story, the characters talk about nested levels of simulation and how slightly disheartening is to know that they are not in the top layer, therefore not "real".

Afai(!)k, there might as well not be a top layer but infinite nesting -- or, even more charmingly, endless recursion, each simulation containing not another layer, but another iteration of itself. This at least would eliminate the embarrassment of being "less real" than the above layer.

Already exists, well at least the movie does - http://www.imdb.com/title/tt0139809/

edited: initially linked to the wrong movie

I am not sure about the implausibility you mention.

"There are worlds who are simulations" !== "Most / all worlds are simulations". The second assumption is possible but by no means implied by the first. If we could create such complex simulations, it would prove only that it's possible that we live in one.

On the bottom end of the stack, for such thought exercises ordered by descending charm, it could be that we live in a simulation created by someone / something that exists in the real reality, and we aren't even in a sophisticated pinnacle of technology achievement like a supercomputer, but in the real reality equivalent of a cheap videogame given away as a real reality equivalent of swag: "Universe 2000, Acme Inc special edition".

Ouch. What a depressing thought.

The problem with Occam's Razor is that the simplest explanation for anything is:

      p AND ~p --> TRUE

The evil demon of skepticism is both evil and a demon.

That's modern philosophy for you. It's the guys who believe they're excluded from science and regurgitate unscientific discussions ad nauseam.

These complaints are ridiculous. Of course philosophy is going to deal primarily with philosophical discussions, and not with scientific ones, that's the job of science!

If you're trying to claim that only scientific ideas are worth entertaining, then the problem is that that claim itself is not scientific.

The commenter you're responding to does not even understand the problem if he thinks science can solve it, as others have pointed out.

Have a look at some articles on philosophy of science. You might not like them, but contemporary philosophy is very much engaged with scientific practice: http://plato.stanford.edu/contents.html.

Or, for that matter, look at Hillary Putnam. Notice that he was a rather accomplished mathematician: https://en.wikipedia.org/wiki/Hillary_Putnam#Mathematics_and.... I believe he also had an extensive knowledge of physics, though I don't think he had any discoveries in the field.

(Edited to be a little nicer).

Without "modern philosophy" the idea of falsifiability would not be a major component of the modern science. Much of what is now considered to be standard scientific practice is the product of Karl Popper's philosophical work.

Far from being excluded, philosophers have defined a large chunk of what modern science is.

I think this vastly overstates Popper's influence. First, if you're trying to say that he's responsible for how science is done, I think that's flatly untrue. Popper's role is to describe and explain scientific practice, and understand how it is effective in producing understanding (assuming it does so--and most philosophers of science tend to agree).

If you mean that he's responsible for our understanding of science, that's debatable. Outside of philosophy, Popper is extraordinarily well known, and you can't avoid people speaking as if falsification is all there is to philosophy of science. Within philosophy, he is respected, but I don't think his particular views are particularly popular.

If Hillary Putnam practices 'quack philosophy' then it is only because philosophy admits duck typing. And alas, it's duck typing all the way down to the turtle.

If we are brains in vats, then the hypothesis that we are brains in vats is only brains-in-vats-falsifiable, unless one includes the very premise of metaphysical reality that Putnam is suggesting is in need of justification.

Keep in mind that Putnam's paper substantially predates The Matrix and that the search for the premises of scientific rationality goes back at least to Descartes, and that so far the two best solutions are still basically Kant's model of mediated access to reality and claims relying upon a priori that we have direct access to a reality as it exists outside human experience [see Nagal's What is it like to be a Bat?]

http://en.wikipedia.org/wiki/What_Is_it_Like_to_Be_a_Bat%3F

    Yes, you could be a brain in a vat.

This sentence is false, since you do not have any basis to refer to a vat. This is simply the same as talking about pointers in java script. Either you are not talking about pointers, or you are not talking about java script.

    The fun thing about this quack philosophy is that's it's falsifiable [...]

It is actually not, the moment you set up any experiment, I just assert that the experiment is a elaborate simulation, which does not tell us anything about the "true universe."

>> This sentence is false, since you do not have any basis to refer to a vat.

I know what a vat is here in subjective world, I am able to imagine a situation in which such a thing exists somewhere with something like my perceived centre of consciousness within it being fed false data. Should that (or some other solipsistic scenario as yet unimagined) actually be the case I am fully aware I do not have the terms of reference to accurately describe the scenario as I have been relying on false data for my entire life. However an accurate description of the scenario is entirely unnecessary to the thought experiment itself and dismissing the entire argument based on the statement that we cannot properly describe a vat is to fail to address the root of the argument and attempt escape on a technicality.

Or, in other words, you could be a brain in a vat.

I think:

     Yes, I could be a brain in a vat.

Is a better formulation, epistemologically speaking. Since I could be in meat space servicing your brain in a vat and denying that the world that each of us experiences has much overlap. In general, propositions that lend themselves to solipsism tend to form a better basis for discussions around philosophical skepticism.

It's going to suck for all those scientists when they realise their "evidence" is just false data fed to their brains in vats, though.

(Or, more generally, this "quack philosophy" is trying to get us to think about what knowledge is, and you can't understand how science works without thinking about the concept of knowledge).

Yes, you could be a brain in a vat.

That depends on whether by "could be" you mean "I can imagine it", or "I have evidence-based reasons to suppose it is possible."

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