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Epistemic Closure and Skepticism

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Epistemic Closure and Skepticism

treysuttle
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Posted 06/06/09 - 05:11 AM: Subject: Epistemic Closure and Skepticism	#1
Most skeptical arguments presuppose some form of epistemic closure. Consider the following argument: A1. If I know that I have hands, then I know that I am not a bodiless brain in a vat A2. I do not know that I am not a bodiless brain in a vat ---- Therefore, I do not know that I have hands This argument follows the valid argument form Modus Tollens. Although there are many ways in which such skeptical arguments have been challenged, one has been to challenge the entailment of the first conditional. If it is the case that I can know that I have hands without knowing that I am not a bodiless brain in a vat, then the argument never gets off the ground. The closure thesis states that an operator on the antecedent holds on the consequent. In other words, operators hold across entailment. This is evidently the case with certain operators. Consider the following: A1. If p --> q A2. (now closure): If p is true --> q is true Clearly if A1 holds then A2 holds. To reject A2, one must reject A1. Closure also seems to hold across modal operators. A1. If p --> q A2. If necessarily p --> necessarily q A3. If possibly p --> possibly q But what about epistemic operators? Some epistemic operators seem just as evidently not to hold across entailment. Consider: A1. If p --> q A2. If believes p --> believes q Now, one response here is to note that if someone believes p, and p entails q, then that person is justified in believing q. This is true, but is not what the entailment states. The entailment states that if one believes p, then one believes q. We could of course state an abundance of cases in which we believe certain propositions, and those propositions entail other propositions, when we do not believe those other propositions. Certain basic principles in physics that I believe entail other principles in physics. Not only do I not believe some of those principles...I am not even aware of them! I could not even infer those principles if I sat down and thought real hard about it. Mathematics also provides an abundance of pretty clear examples where belief doesn't hold across entailment. What about the epistemic operator 'know'? A1. If p --> q A2. If knows p --> knows q One avenue for the skeptic is to show that, like truth and modality, and unlike belief..'knows' holds across entailment. Another avenue is to show that sometimes 'knows' does not hold across entailment, but sometimes it does; and in the skeptical scenarios in question (specifically 'global' skeptical scenarios) 'knows' is of the form that does hold across entailment. While I do believe that there are good reasons to think that 'knows' never holds across entailment, that is not the strategy I will take here. My strategy is to suggest that whether 'knows' holds sometimes or not, a strong argument can be made that it does not hold in the sort of global skeptical scenarios like those offered by traditional brain in a vat arguments. Let us say that a belief is sensitive to the degree to which one could be made aware of some possible defeater that would undermine that belief. A belief is insensitive to the degree in which it is not sensitive. So, let's say that I believe that my car is in my driveway. That belief is highly sensitive because there are an indefinite number of potential defeaters that could undermine my belief. My car could be stolen....I would say anything that is at least nomologically possible could be a potential defeater to my belief. This substantiates the importance of justification regarding empirical beliefs. One is rightly tempted to say that I am not justified in believing that my car is in my driveway until I see my car in my driveway. Even then we might require more (it could be a very well made 'facade-car'). But most of us (and not yet bringing in global skeptical scenarios) would at some point be satisfied that I have a justified, true, belief that my car is in my driveway. Now bring in global skeptical scenarios like that offered by bodiless brain in a vat scenarios. How sensitive is the belief: 'I am not a bodiless brain in a vat'? It is absolutely insensitive! There are no possible defeators (in any possible world) that would or could substantiate -- to any degree, that I am in fact not a bodiless brain in a vat. The reason is simple: In any possible world in which I am a bodiless brain in a vat, the world appears exactly the same as if I am not a bodiless brain in a vat. In many worlds in which my car is not in my driveway, those worlds do not appear exactly the same as many worlds in which my car is in my driveway. Turning back to the skeptical argument proper...consider the use of 'knows' in the antecedent and in the consequent. Just as the case with my car...there are any number of possible worlds in which if I do not have hands then I could know that I do not have hands...and worlds in which I do have hands and would thus know that I have hands. But there are no worlds in which I am a bodiless brain in a vat and would know that I am a bodiless brain in a vat (consider if someone seriously told you that you were a brain in a vat...would you believe them? Or if you saw yourself on a TV screen, via a camcorder, as a brain in a vat....would you then really believe?...I suspect not. Even if eventually you did come to believe...you would not know it, in the sense in which you would know that you have hands in a world in which you are not a brain in vat). In order for closure across entailment to hold, the operator must have equivalent semantic content. Consider, modal entailment does not hold if say, the antecedent employs de re necessity while the consequent employs de dicto necessity: If the morning star is necessarily the evening star, it does not hold that necessarily, the morning star is the evening star. The first case says that something has the property of being identical to itself (an uncontroversial logical claim)...the second says that it is necessarily the case the the morning star is the evening star (an empirical claim that could have turned out false had the world been different). My suggestion is that there is just such a semantic shift in the operator 'knows' as employed in global skeptical scenarios. Given that the operator in the antecedent is highly sensitive, while the operator in the consequent is very strongly (if not absolutely) insensitive, it follows that even if sometimes closure across entailment holds for epistemic operators (which I doubt), but even if it does, entailment does not hold when the semantic content across operators radically shifts from one degree of sensitivity to a standard that is radically insensitive.

sqeecoo
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Posted 06/06/09 - 06:38 AM:	#2
I agree with you inasmuch that this skeptical argument puts way too much weight on the meaning of "know", which helps everyone get entangled into fruitless discussions on the definitions of knowledge and justification. On the other hand, if there really existed a clear procedure of justification that relied less on intuition and more on something resembling logical rules of procedure, we wouldn't have nearly as much problems with the meanings of words. I don't see why people focus on this skeptical argument so much when there is a much simpler and better one that mostly gets ignored: Let's look at justification as a method of belief selection. How does any kind of justification (partial or conclusive or contextual etc..) improve our epistemological position, if any reasons we can give for a particular belief will only shift the problem to those reasons, or to the reasons given for these reasons, etc. What is gained by this process? Can justification do anything but shift the problem somewhere else, and can anything be gained from this? EDIT: On a lighter note, the problem of infinite regress: http://www.daisyowl.com/comic/2009-05-19 EDIT2: Your "sensitivity" looks a lot like "falsifiability", so I support it completely. I think we should try to find falsifiable or at least criticizable hypothesis (i.e. those "sensitive" to some "defeators", in your terminology). But I'm not sure how your sensitivity is relevant to knowledge in the sense of justified true belief. Justification is about verification, so where do "defeators" come into play? Edited by sqeecoo on 06/06/09 - 07:08 AM

treysuttle
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Posted 06/06/09 - 07:25 AM:	#3
Thanks sqeecoo, I don't read it as the skeptic is putting too much weight on 'know'. I think, as epistemologists, we are all primarily concerned with the operator 'know' (to kinda be crude with it). That is really what we are interested in. What I take the skeptic to be doing in the BIV type arguments, for lack of a better way of putting it, is equivocating. But I don't think this is intentional (on the part of many skeptics anyway). It the result of not recognizing the nuances in certain philosophical technical terminology. This is essentially the 'semantic shift' taking place. I think metaphysicians (via thinking about stuff like modal operators) are more sensitive to these issues than perhaps many epistemologists are. The skeptic means one thing by 'know' in the antecedent, but something else in the consequent (but because the 'term' is the same...and can legitimately be used in both senses (although not as a conjunction in an argument)...it obscures this...UNTIL we think about justification....which is part of the at least necessary conditions for knowledge). I don't think justification for empirical facts can rest of logical rules. This is exactly what the skeptic wants to sneak in. From that it is logically possible that I am a brain in a vat doesn't imply that I do not know certain empirical facts. If it was the case that justification relies on logical rules, then anytime I am justified in believing p, I would be justified in believing q. But closure doesn't cover 'justification'. I may be justified in believing that I see a barn without being justified in the belief that the barn is not a really good facade. But otherwise is exactly what the skeptic wants us to think -- that we must be justified in believing that x is not a barn facade in order to be justified in believing that x is a barn. You point about 'belief selection' is interesting. The problem as I see it is not the shift....the skeptic has a valid position...within a certain conception of what it means to 'know'. But in other conceptions of what it means to 'know', she does not. Certain skeptical arguments...like BIV and barn facades, conflates these two. But if we look at how epistemic operators work across entailment, then we can see that there is a radical semantic shift taking place (it is the notion of justification that makes this aware to us). Thus, we can legitimately say both 'I know that I have hands' and 'I do not know that I am not a brain in a vat'.

treysuttle
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Posted 06/06/09 - 07:36 AM:	#4
Yes, sensitivity (as I understand it) is much like falsification, but a little different. In relation to JTB, it >seems< to be the case that we really could never be justified in a belief that is insensitive. Consider, if I were a brain in a vat, I would believe everything that I would believe even if I were not a brain in a vat. It's similar to 'falsification', because in most (if not all) worlds, there is no possible way in principle to falsify the claim that 'I am (am not) a brain in a vat'. In this sense, I guess you might think of falsification as a kind of cover all, where sensitivity connotes the degree of possibility for falsification (i.e. potential defeaters). My claim (as you probably intuit) is that falsification is context sensitive. But I don't think that thesis is something that I have to actively substantiate (as relevant to knowledge in general) if we see that there is something fundamentally different about claims that can potentially be falsified and cannot be even in principle be falsified. Ultimately, its a mistake to use the same term 'knowledge' to cover both circumstances in arguments about whether we have knowledge or not. If it is not a mistake...the skeptic needs to clarify her argument.

treysuttle
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Posted 06/06/09 - 07:40 AM:	#5
At least one difference in falsifiability and sensitivity. It might be the case that in no possible world could one falsify the claim that 'God exists'. But this claim is sensitive. In some worlds where God does not exist, I do not believe in God and I am justified in not believing in God. Presumably, in no world am I not a brain in a vat and justified in believing that I am not a brain in a vat... Thus...the semantic shift again is pretty clear. Practically all global skeptical arguments seem to ride on it.

Cuthbert
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Posted 06/09/09 - 05:21 AM:	#6
treysuttle wrote: Turning back to the skeptical argument proper...consider the use of 'knows' in the antecedent and in the consequent. Just as the case with my car...there are any number of possible worlds in which if I do not have hands then I could know that I do not have hands...and worlds in which I do have hands and would thus know that I have hands. But there are no worlds in which I am a bodiless brain in a vat and would know that I am a bodiless brain in a vat (consider if someone seriously told you that you were a brain in a vat...would you believe them? Or if you saw yourself on a TV screen, via a camcorder, as a brain in a vat....would you then really believe?...I suspect not. Even if eventually you did come to believe...you would not know it, in the sense in which you would know that you have hands in a world in which you are not a brain in vat). I wonder whether this argument begs the question against the sceptic. According to the sceptic, and contra treysuttle, there are no possible worlds in which I do not have hands and can know that I do not have hands. That is because it's impossible for me to know anything. If the distinction between sensitive and insensitive beliefs depends upon the distinction between propositions such that there are worlds in which we can (or alternatively cannot) know them to be true, then the sceptic will reject the sensitive / insensitive distinction. For him, all beliefs are equally insensitive to states of the world, for we can know none of them to be true. It seems that an anti-sceptic argument that depends upon the distinction you've drawn already presumes scepticism to be false. Thus, we can legitimately say both 'I know that I have hands' and 'I do not know that I am not a brain in a vat'. It's an interesting approach. But still, perhaps we know that we aren't brains in vats and we also know that, for all we know, we might be. That is, we can know things and consistently claim knowledge and admit fallibility.

endless nameless
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Posted 06/09/09 - 07:28 AM:	#7
treysuttle wrote: At least one difference in falsifiability and sensitivity. It might be the case that in no possible world could one falsify the claim that 'God exists'. But this claim is sensitive. In some worlds where God does not exist, I do not believe in God and I am justified in not believing in God. I'm finding your thoughts on sensitivity quite interesting, but just what sort of justification are you referring to here? Is it the fact that the burden of proof for God's existence rests with theists? If so, and maybe I'm missing something here, it seems like you would be justified in disbelieving in God's existence in all possible worlds where God does not exist, so I'm not quite sure what you mean here.

oag
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Posted 06/13/09 - 03:01 AM:	#8
Cuthbert wrote: That is, we can know things and consistently claim knowledge and admit fallibility. What sort of definition does this give to the word know then? Isn't it stating that we believe we know but that such knowledge might be incorrect? Since the whole thing really does hinge upon the word know it must be clearly defined and consistently applied with only that narrow definition in order to avoid the semantic stumbling. There are two choices. Know can be defined as what we find to be consistent, repeatable and predictive. Know can be defined as absolute certainty. Let's apply the two. We can know we are not a BIV because all evidence suggests otherwise and we collectively agree that this is not the case. We can not know that we are a BIV because it remains a possibility. We have no means by which to absolutely discount this.

treysuttle
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Posted 06/13/09 - 06:34 AM:	#9
I'm not sure that I am begging the question against the skeptic, because I don't claim skepticism to be false...at least global Cartesian skepticism. My strategy, instead of debunking the skeptics argument, is to say the skeptics argument is sound. Given the way that the skeptic is using 'know' in the first premise...it is the case that we don't know that we have hands...or know anything for that matter (even that the skeptics argument is sound?). But from this it doesn't follow (at least I'm trying to suggest) that in all legitimate contexts in which we are concerned with knowledge, we have no knowledge. I know just fine that I have hands right now...because in this context of knowledge (when the term 'know' is used 'sensitively'), logical possibilities (of the sort the global skeptic posits) are not relevant to my knowledge. It's not (at least it seems to me) that when the skeptic does say 'Ok, let's do some epistemology...couldn't you be a brain in a vat' that now I must retract my earlier claim to know that I have hands. Instead, the skeptic has enacted a uniquely philosophical semantic shift in her use of terms (in distinction to how we typically use the term when talking about stuff like knowing that I have hands or knowing that my computer is on my desk right now). Perhaps one way of making this cognizant is to pre-define our terms. It obviously seems to me that the skeptic is requiring an extremely high degree of certainty in order to know quite mundane facts. Outside of the 'academy', we are fine with various degrees of warrant for having knowledge...degrees much lower than the absolute certainty the skeptic requires. It is acceptable for the skeptic to reject the distinction between sensitive and insensitive beliefs...because she is only concerned with insensitive beliefs, in the sense that we have to know something that we cannot possibly know, in order to know anything. If mundane knowledge claims are contingent on knowing something that cannot possibly be known...then we don't have knowledge and I accept that. What I don't accept is that mundane knowledge claims...and even very sophisticated inferences, are contingent on knowing something that cannot possibly be known -- in contexts when we are not using the term 'know' insensitively. oag: "We can know we are not a BIV because all evidence suggests otherwise and we collectively agree that this is not the case." The evidence cannot suggest otherwise (this is just my point about sensitivity)...if you are a brain in a vat..the evidence would be the exact same as if you were not a brain in a vat. Anything you point out as evidence that you are not a BIV, would be identical to what is the case if you are a BIV. But notice that this is not the case if we do not mean by 'know' what the skeptic means in skeptical arguments...but mean by 'know' something like adequately warranted belief...in which case then it is perfectly admissible to say that you know that you have hands because you see them..and if you didn't have hands (if they were cut off in an accident) then you would see nubs - not hands. BUT, even then, it is not admissible to say that you know that you are not a BIV...but then you have committed a semantic shift...from using the term 'know' in one way..to using the term 'know' in another way.

oag
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Posted 06/14/09 - 10:12 PM:	#10
treysuttle wrote: Outside of the 'academy', we are fine with various degrees of warrant for having knowledge...degrees much lower than the absolute certainty the skeptic requires. I've been having this difficulty on another forum and came here in search of back-up, if you will. I am finding some new terminology that might be helpful as well as minds that seem more capable of grasping and expressing the semantic distinction that hangs people up so easily. It is acceptable for the skeptic to reject the distinction between sensitive and insensitive beliefs...because she is only concerned with insensitive beliefs, in the sense that we have to know something that we cannot possibly know, in order to know anything. Here, to me, is the key distinction. I suggested that every time we use the word know in a conventional sense we are merely stating an opinion. Several people have gone berserk over that for 20-something pages. Here you succinctly state what I have contended, that once we define the word know as beyond Cartesian doubt, and then recognize that humans are not capable of such a thing then the only thing that remains is beliefs. By convention then we simply label those beliefs which are most firm (evidenced, compelled, repeatable, predictive, etc.) as knowledge. The evidence cannot suggest otherwise (this is just my point about sensitivity)...if you are a brain in a vat..the evidence would be the exact same as if you were not a brain in a vat. I used the color coding to indicate the lesser, the conventional usage of the word know. In that sense you and I (pretty much) know that we are not brains in vats. By evidence I was merely speaking to how unlikely such a scenario is. Evidence is not really the best word so I apologize for being lazy. BUT, even then, it is not admissible to say that you know that you are not a BIV...but then you have committed a semantic shift...from using the term 'know' in one way..to using the term 'know' in another way. Yep. See? It is that easy, that simple. I thought so. If we want to confine the word know to conventional usage then we know plenty of stuff. If we want to elevate the discussion to a slightly different plane then we can use know in the sense of objective knowledge beyond Cartesian doubt but it remains a hypothetical, beyond human ability and we don't know anything (other than cogito ergo sum). Thus we are left to redefine what humans conventionally consider knowledge and that leaves only beliefs. I can't understand why I seem to be the lone voice crying in the wilderness over there and why this eludes so many seemingly very clever people. The bottom line is that we say we know actually are beliefs and that is what allows them to change, allows us to know something more or something altogether different as we get new information. It seems obvious to me. Edited by oag on 06/14/09 - 10:21 PM. Reason: fix quote tag

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