Consider the hypothesis that you are a disembodied brain floating in a vat of nutrient fluids. This brain is connected to a supercomputer whose program produces electrical impulses that stimulate the brain in just the way that normal brains are stimulated as a result of perceiving external objects in the normal way. (The movie ‘The Matrix’ depicts embodied brains which are so stimulated, while their bodies float in a vats.) If you are a brain in a vat, then you have experiences that are qualitatively indistinguishable from those of a normal perceiver. If you come to believe, on the basis of your computer-induced experiences, that you are looking at at tree, then you are sadly mistaken.I would argue that while this comparison immediately leaps to mind, the real problem raised by the Matrix is much deeper. The brain-in-a-vat Gedankenexperiment implicitly assumes both that there is a real world, and that the computer-generated illusion isn’t it. In the Matrix films, however, this isn’t quite so straightforward.
Most of the simulated worlds we’re familiar with mimic reality at a very high level of emergence. Physics engines used in video games, for instance, copy the effects of Newtonian physics with macroscopic objects treated as primitives. But in the real world, the behavior of macroscopic objects emerges as a consequence of the crowd behavior of microscopic objects. Since the physics engine does not simulate these, it must substitute other causes to reach the same effect.
Take, for instance, the fact that two solid objects which collide will bounce away from one another rather than pass through each other. In the real world, this will occur because the particles which make up the solids will electrically repel each other; in a physics engine, this effect must be created with explicit collision detection and response rules.
But what if our physics engines had a great deal more computing power at their disposal, and simulated physics at the microscale, allowing macroscopic effects to emerge? In such a situation, the artificiality of the physical effects is less clear. They are not explicitly created by the programmer, but rather appear as a result of the same processes by which they come about in real life. As artificial intelligence researcher Steve Grand writes in his book Creation:
A computer simulation of an atom is not really an atom.... But if you make some molecules by combining those simulated atoms, it is not the molecules’ fault that their substrate is a sham; I think they will, in a very real sense, actually be molecules. ... the molecules made from it are second-order simulations because they are made not by combining computer instructions but by combining simulated objects.Suppose we were to take this to its logical conclusion and posit a simulation based on the still-undiscovered Grand Unified Theory of physics, that is, a perfect physics engine from which even the behavior of the tiniest particles emerged from underlying rules rather than being directly simulated.
If we found ourselves in such a simulation, there is no way we could ever find it out; indeed, there is no way we can state with confidence that we are not. We don’t know anything about the nature of the ultimate substrate of this world. It could be a computer, the mind of God, or turtles all the way down. Yet this is the world which we refer to as “real.” I think we’re justified in referring to it as such, but in so doing we have to accept that being real does not necessarily exclude the possibility of being a computer simulation.
Although its portrayal is not entirely consistent, the fidelity of physical behaviors in the Matrix suggest that it’s just such a perfect simulation. The human occupants of the Matrix are shown to be aliens to that world. But it can never be entirely clear that the “real world” to which they escape is less of a simulation than the one they left, or that the natural inhabitants of the Matrix—the programs—aren’t less flesh-and-blood than their jacked-in counterparts. Indeed, both of these conclusions are hinted at in the second and third films.
4 comments:
Strangely enough I had an in-depth, independent discussion the other day with a friend of mine on how the buoyant force would behave if it were caused by little turtles. We decided that they would have to act synchronously, and that is the cause of resonance and that's when things blow up.
Your discussion reminds me of the WSOGMM analogy from The Hitchhiker's Guide, and how we, as sentient beings, develop enormous filtering capacity to enable us to function normally in this vastly chaotic universe. The problem of whether we are living real or simulated lives has no effect on our daily normal function, since either way we define normal by the viewpoints of ourselves from inside those lives. The so-called quality of life is dependent on a set of characteristics defined internally to the problem of life. Since largely the drive to solve problems evolved as a means to improve the quality of life, the drive to solve problems is in itself internally referenced to life and the problem of the nature of life itself falls outside the realm of problem solving if the internal characteristics of life viewed from the perspective of the living remain the same. Thus, not only is the brain-in-a-vat problem unsolveable from anyone living life, there isn't any function to solving the problem.
It breaks down to "so you're a brain-in-a-vat - what are you going to do about it?"
Hi david,
Very insightful, and I would agree 99% with what you say. The other 1% is for those who choose to reject the Matrix.
I propose that when you say that there isn't any function to solving the problem, you are committing an extremely common error which I will call the fallacy of naked utility. The fallacy of naked utility is to suppose that an activity or tool can meaningfully be declared “useful” or “useless” without reference to an end which it would be useful or useless for. As D. Adams would remind us, the only thing that is useful without qualification is a towel.
There are individuals—mystics, philosophers, scientists—who pursue hidden knowledge of the nature of things because they find it immediately pleasurable to do so. Rather than setting this kind of knowledge aside as a special case (“‘pure’ knowledge”), I would argue that it is pragmatic knowledge toward satisfying a human end for that particular community of individuals. This community would see a function in having a way out of the vat.
But all this is a small caveat. I agree with you that the brain-in-a-vat problem is unsolvable and pointless for the vast majority of people, whether one takes it as a problem for epistemology or metaphysics. And I agree, too, with your pragmatic (engineer’s?) outlook that places the ultimate ground of scientific concerns in the lived world rather than in some transcendental impartiality.
Granted, its all well and good if contemplating an escape from the brain-in-a-vat improves the individuals quality of life. However, that falls under the more general category of contemplation for contemplation's sake - the improvement in the quality of life comes from the joy of contemplating, not from the contemplation of that specific subject, and the actual problem being worked upon becomes moot as long as it falls under the general subject matter of "discovering knowledge."
The improvement of the quality-of-life was the "reference to the end" that the activity of contemplating the brain-in-a-vat would be useless for. However, I wasn't really discussing the lack of the utility of the tool itself, but the lack of ability to use the tool, because of the perspectives that we are offered on the problem. Using a pair of scissors actually requires two tools, the scissors themselves and the opposable thumbs to operate them. Without the necessary outside perspective of life to act as our "opposable thumbs" as references for solving the brain in a vat problem, the "scissors" of the reasoning required to solve the brain-in-a-vat problem become unusable.
Remember in the Matrix (2nd movie) they discuss how the One is a continuum - that once Zion is destroyed, the One choses new humans to "escape" the Matrix - but always those who escape the Matrix must be helped from someone outside the Matrix. Not even the One can escape on his own, relying on the previous group of humans to help him escape, because he does not have the requisite outside perspective (except for the very first One, who, as explained by the Architect, was helped to escape by the computers, who also have an outside perspective, as a solution for dealing with the One).
Good points. I just want to mention that it’s still an open question, for many philosophers, whether we possess those “opposable thumbs.” The reason has to do with the nature of illusion.
An illusion, by definition, is not what it appears to be. It doesn’t follow, however, that it could be anything other than what it appears to be. It still must be the sort of thing that can produce that particular appearance. To pick two random things out of the air, you can’t create an illusion of a bicycle with a rotten grapefruit.
The “brain-in-a-vat” (BIV) scenario is only philosophically problematic because we can imagine that a powerful supercomputer really would be able to create such an illusion. We can dismiss out-of-hand, for instance, a scenario which is identical to BIV but that replaces the supercomputer with a block of cheddar cheese.
Thus, if we were ever able to determine that we were in an illusory world, it might be possible to work out a number of things about how the illusion is being produced, and what the “real” world is like, even with our limited perspective. One might even say that this has already happened, with the facade of classical physics—which describes the appearance of our lived-in world quite well—giving way to quantum mechanics.
Of course—and this goes back to your original point, and mine—to say that the world we find familiar is being sustained by a mechanism we find exotic is not to say that it is less real, if it is the world we have always lived in and known.
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