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Topic: Micah Sparacio: Metaphysical Considerations for External World Skepticism
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posted 14. June 2004 16:19
Metaphysical Considerations for External World Skepticism
by Micah Sparacio
Abstract: External world skepticism (EWS) has intuitive force. If I don’t know that I’m not a brain in a vat (BIV), then how can I possibly know that I have two hands? By the principle of closure, it seems that not knowing that I’m not a BIV implies not knowing that I have two hands. Epistemological solutions to the problem have typically relied on one of three strategies: reject the skeptical scenario (e.g. I know that I’m not a BIV), deny the principle of closure, or contextualize knowledge. Each of these solutions seems to deny something intuitive regarding the force of EWS. Drawing on Chalmers recent work , I will argue that the problem of EWS is intimately tied to how we conceive of the proper relationship between our ontology and our concepts, and that a metaphysical analysis can provide clarity on the issue. However, I reject Chalmers’ thesis that metaphysics can solve global skepticism about the external world. Rather, I make a weaker claim; namely that the bite of EWS is significantly weakened if we consider our ordinary epistemic response to the micro-macro relationships of the physical world. I conclude with a dilemma: either contemporary physical theories should leave us skeptical about our knowledge of the macro physical world or external world skepticism is philosophically benign.
To read the entire paper, click here.
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Evan
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posted 14. June 2004 18:59
I vote for the latter: "external world skepticism is philosophically benign." There is just no useful reason to doubt what is given to us - the perceptual sense of an external world.
Among other things, if one seriously adopted EWS, how would that change anything about how one behaved?
There are other philosophical positions that I equally benign. I like Last Thursdayism - the belief that everything in the universe was created last Thursday, including all the evidence that makes it look like things existed before then.
This is not meant to be a flippant rejoinder - I've been told that the ancient HIndus have a myth that the God of destruction and the God of creation are engaged in an endless struggle whereby world is destroyed and recreated a billion times a second, each time slightly different than the time before.
All of these ideas claim that the world we think we perceive is an illusion of some sort. I'm willing to believe that this indeed might be correct. But the problem is that we have no way of knowing what in fact is correct, if anything - like a fish in water or a two dimensional creation on the surface of a sphere, we are so existentially and thoroughly immersed in the world that we think exists that we have no way (other than enteraining completely untestable philosophical speculations such as is being done here) of ever knowing what might be “outside” the world.
My 2¢
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Rex Kerr
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posted 15. June 2004 03:31
I think Micah's exactly on target. I'm not entirely sure what the difference between contextualism and Micah's position is--Micah's arguments sound like arguments in favor of one specific context.
My view of the brain-in-a-vat scenario is essentially the same, although I view it as an algorithmic learning problem. Viewed in that context, you actually *do* have a brain in a vat (a body). At the moment, it's not been demonstrated that knowledge can be captured and used by an algorithmic process. Eventually, hopefully the field of neuroscience will have an answer. In the meantime, if we postulate that systems can replicate our ability to know things, and we can show that they are a brain in a vat (or that our brains are brains in a vat), then the only way for the metaphysical BIV to have any important consequences would be if we accepted the proposition that whether something was justified or not (or was knowledge or not) depended on factors that made absolutely no difference to anything anyone ever perceived.
One could define relations that did depend on irrelevant external factors, but I would argue that it's unhelpful to do so.
So I think that not only is Micah's position essentially right (as I understand it), but that progress in the field of neuroscience is likely to confirm that view.
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posted 15. June 2004 07:41
A response from David Duncan
1. I know that I am in Princeton, New Jersey.
2. I do not know that I am not a brain in a vat.
3. If I do not know that I am not a brain in a vat, then I do not know that
I am in Princeton, New Jersey. (Principle of Epistemic Closure)
The conclusion seems to follow because there is an equivocation on the
strictness with which the word "know" is used between premises 1 and 2.
I am reasonably certain that I am in Princeton NJ. I can confirm this by
asking person after person. I can examine my address on the mail. I can
see the town¹s name on the outskirts of town. I can examine my location
against a map as I travel to confirm key topographical landmarks. I cannot
find evidence to contradict the notion that I am in Princeton, NJ.
Therefore, according to everything I know or can discover, I am indeed in
Princeton, NJ.
So why can't I be similarly certain that I am not a brain in a vat? Because
every detail of the experience of being in Princeton, which is a reasonably
certain experience, might be produced by some mad scientist in a far off
universe poking a brain which causes experiences I feel are my own.
In other words, I cannot be sure that I am NOT a brain in a vat, in the same
sense that I can be sure that I am in Princeton NJ, because the sense of
certainty with which the word "know" is used in each case, varies.
I am reasonably certain that I am in Princeton NJ and I am reasonably
certain that I am NOT a brain in a vat. So I "know" that I am in Princeton,
NJ by this reasonable standard of certainty and evidence.
But I cannot be absolutely certain that I am NOT a brain in a vat because it
is impossible to refute. I can find no evidence whatsoever either to
support or refute the possibility. It is possible because I imagine the
possibility and cannot rule out what I have imagined, and I cannot rule it
out because my knowledge is not comprehensive enough to discern every corner
of the universe to know that I am actually NOT a brain in a vat. So I do
not "know" that I am NOT a brain in a vat by this more extreme sense of the
word "know."
Clearly, the word "know" changes in the sense of certainty with which it is
used from premise 1 to premise 2, and because it has changed senses, the
conclusion does not follow.
It does not follow, because even if I cannot be sure that I am not a brain
in a vat by the most extreme sense of the word "know," I can still be sure
that I am in Princeton, NJ, by the reasonable sense of the word "know."
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Evan
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posted 15. June 2004 08:33
It is true, as Micah writes, that there is and always will be a type of uncertainty about our knowledge of the physical world: no matter how many “levels” of understanding we go (atomic structure, then quarks, etc.), there might be some deeper level of reality of which that part we are studying is just a manifestation.
It is also true, as Micah says, that our scientific knowledge shows the world to be extremely different than our naive perceptual intuition of it: my table is not “really” solid, etc.
Two questions arise: (1) what are we to make of this? - what level of skepticism should we adopt and what difference should that make in our lives?, and (2) how is this different than speculations like external world skepticism or Last Thursdayism?
One critical difference is that our scientific knowledge has been formed by a world-wide agreement to use certain methods for establishing that knowledge (and among other things, that method assumes that the external world is real.) This knowledge is tested, is found to be consistent, works in the sense of accurately predicted how the world is going to behave, and son; and is ultimately agreed upon by millions of people. It is communal and collaboratively based knowledge. Therefore, a scientist, thinking as a scientists, accepts it as the best knowledge we have about our physical world.
A scientist (or anyone) , however, acting more broadly as a human being, can and probably should have some type of skeptical orientation about scientific knowledge, both in the sense that the “ultimate” source or nature of the physical world is probably unknowable and it is possibly of a kind entirely unfathomable by us; and in the sense that there is a great deal about the world that we need to “know” that science cannot provide us: values, aesthetics and emotional judgments, and so on.
I am a Feynman fan: he once wrote (and I paraphrase), “I would rather live with uncertainty than believe things that are not true.”
I also am a fan of Eastern philosophy: A certainly underlying skepticism about all knowledge is not only desirable, it is in fact the key to liberation. Knowing that one doesn’t know is one of the goals of the spiritual path, because it allows one to become free of from the ego’s attachment to its theories.
And I am a fan of existentialism, in this sense: Given that ultimately we don’t know, we are therefore forced to choose (there is no escape from this) to act as if we believe that certain things are true even if we are also deeply aware that we might be wrong.
Therefore, ultimately, views such as external world skepticism are dismissed by choice, not by logic.
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charlie d.
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posted 15. June 2004 14:19
Interesting stuff (and philosophically already way over my head!). I have a couple of (possibly naïve) comments:
First, I do not think Micah’s comparison of the epistemological uncertainty derived form the BIV scenario and that derived from the macro-/micro- levels of physical reality really fits. Leaving EWS aside for a moment, while we know that micro-reality is very different from the perception we have of it at the macro level, we also know that that perception is exactly what we would expect to derive from our equally macro sense organs. In other words, we know that reality is one way at the micro level, and that its properties at that level make it look a certain way at the macro level – our senses do not deceive us in that respect. This is no different from our understanding that there are light and sound wavelengths our sense organs can’t perceive, or for that matter that our sense organs and brains can be deceived by things like optical illusions - our reality is still “true” to itself regardless of this. Thus, in my opinion there is really no “fracture”, no fundamental incompatibility between the two levels, as there is if we were BIVs.
The second point, which may be just a nitpick, is that I find the BIV scenario easily logically dismissable on the basis of its implausibility: even if some civilization had mastered the BIV technology to perfection, it is much (MUCH) more likely for a brain to be in a real, living being than in a vat. A more meaningful scenario in this respect is Nick Bostrom’s “computer simulation” idea. IIRC, he argues that, assuming we believe it is likely (perhaps even unavoidable) that progress in computing technology eventually will allow computers to carry out simulations in which the simulated entities will be able to display entirely human-like attributes (including psychological ones), and will interact with a highly realistically simulated physical world, and inasmuch at some point there may be many more of such simulated entities than humans ever existed (which is also plausible, assuming ever-expanding computer power and limited resources for human population growth), than it is more likely than not that in fact we are – right now - one of such entities, rather than “real” human beings. (In other words, we in fact may be just computer simulations wondering whether we are actually BIVs!)
Bostrom’s scenario makes it a little easier to reach an acceptable resolution, however – as computer simulations, this is our reality, even if it is artificial (the same argument is harder to make for BIVs, though still possible perhaps). Which I think brings us close enough to Micah’s conclusion, and to me can be boiled down to the following: as long as the world we perceive (real or simulated) is consistent to itself, predictable and logical (i.e. understandable), then there really seems to be no practical difference either way. If the scientist sticking probes in the BIV, or the programmer who designed the simulation we are part of, make our fictitious worlds behave logically and consistently, then there is no problem, from a utilitarian point of view, with us using our perceptions and logical tools to try to make sense out of it. If and when our perceived worlds will cease to behave predictably and logically, the issues of whether we are BIVs or computer simulations will become epistemologically and practically relevant.
The real issue, then, is whether we have already reached this point, for instance with quantum physics or supernatural events (assuming one believes in either), but we prefer to just keep fooling ourselves, and refuse to draw the necessary, if unpleasant, conclusions. (In that respect, I think it would be an interesting and paradoxical eschatological perspective if the supernatural, miraculous events of the End of Days resulted in our realization that we are indeed just computer simulations!) However, my opinion on this is just as good as the one of the brain in the next vat. ![[Wink]](wink.gif)
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RBH
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posted 15. June 2004 15:01
Somewhere in the dim past I remember reading a science fiction short story in which the protagonist is a psychologist who got interested in the roots of humor. After long and arduous researches, he finally concluded that humor has no human roots and must have been imposed on humanity by some external intelligence. The short story ends with the psychologist realizing that when the experimental subjects in a study comprehend the conditions of an experiment, the experiment is over. The last sentences are about the psychologist trying and failing to think of a single joke, and the faint impression of a giant laboratory cage being re-arranged.
RBH
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