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- Bryan Frances (2008). Live Skeptical Hypotheses. In John Greco (ed.), Oxford Handbook of Skepticism. Oxford.Those of us who take skepticism seriously typically have two relevant beliefs: (a) it’s plausible (even if false) that in order to know that I have hands I have to be able to epistemically neutralize, to some significant degree, some skeptical hypotheses, such as the brain-in-a-vat (BIV) one; and (b) it’s also plausible (even if false) that I can’t so neutralize those hypotheses. There is no reason for us to also think (c) that the BIV hypothesis, for instance, is plausible or probably true. In order to take skepticism seriously it’s sufficient to hold (a) and (b); one need not hold (c). Indeed, philosophers who accept (a) and (b) never endorse (c). Show me a philosopher who suspects that he is a brain in a vat and I’ll show you someone who is deranged! That’s one thing that bothers undergraduates in philosophy. They object: why on earth do some philosophers take the BIV hypothesis to pose any threat at all to our beliefs given that those very same philosophers think that there’s no real chance that the BIV hypothesis is true? Sure, the BIV hypothesis is formally inconsistent with my belief that I have hands, so if the former is true then my belief is false. But so what? Why should that bare inconsistency matter so much? Is this strange attitude amongst philosophers the result of some logic fetish infecting the philosophical community? It is sometimes said that the skeptical hypotheses are not only inconsistent with our beliefs but are explanatory of our experiences, which is supposed to make them more of a threat. But students aren’t fooled: although the skeptical hypotheses may attempt to explain why our experience is as it is, it’s the kind of attempt appropriate for science fiction movies that are all special effects and virtually no plot. No one with any sense of reality will take the evil demon hypothesis to be even tenuously explanatory.
Similar books and articles
Dr. Evil learns that a duplicate of Dr. Evil has been created. Upon learning this, how seriously should he take the hypothesis that he himself is that duplicate? I answer: very seriously. I defend a principle of indifference for self-locating belief which entails that after Dr. Evil learns that a duplicate has been created, he ought to have exactly the same degree of belief that he is Dr. Evil as that he is the duplicate. More generally, the principle shows that there is a sharp distinction between ordinary skeptical hypotheses, and self-locating skeptical hypotheses.
There is a widespread belief among contemporary philosophers that skeptical hypotheses—such as that we are dreaming, or victims of an evil demon, or brains in a vat—cannot definitively be ruled out as false. This belief is ill-founded. In fact it is based on a failure to see that skeptical arguments beg the question. Such arguments assume that reality is not an immediate given of experience in order to prove that reality is not an immediate given of experience. This point is explained and justified in detail. Conversely, however, the realist would beg the question in the opposite way if he tried to prove realism. The conclusion we should reach is that skepticism and realism are problems of immediacy and not of proof. They face us with a choice between alternatives that are not only radically different but also pretty much impregnable and irrelevant to each other. This choice is not arbitrary, for there are grounds to determine it. But the grounds are the immediate evidence and not the arguments.
Skeptics try to persuade us of our ignorance with arguments like the following: 1. I dont know that I am not a handless brain-in-a-vat [BIV]. 2. If I dont know that I am not a handless BIV, then I dont know that I have hands. Therefore, 3. I dont know that I have hands. The BIV argument is valid, its premises are intuitively compelling, and yet, its conclusion strikes us as absurd. Something has to go, but what? Contextualists contend that an adequate solution to the skeptical problem must: (i) retain epistemic closure, (ii) explain the intuitive force of skeptical arguments by explaining why their premises initially seem so compelling, and (iii) account for the truth of our commonsense judgment that we do possess lots of ordinary knowledge. Contextualists maintain that the key to such a solution is recognizing that the semantic standards for knows vary from context to context such that in skeptical contexts the skeptics premises are true and so is her conclusion; but in ordinary contexts, her conclusion is false and so is her first premise. Despite its initial attractiveness, the contextualist solution comes at a significant cost, for contextualism has many counterintuitive results. After presenting the contextualist solution, I identify a number of these costs. I then offer a noncontextualist solution that meets the adequacy constraint identified above, while avoiding the costs associated with contextualism. Hence, one of the principal reasons offered for adopting a contextualist theory of knowledge–its supposedly unique ability to adequately resolve the skeptical problem – is undermined.
Skeptics try to persuade us of our ignorance with arguments like the following: 1. I don't know that I am not a handless brain-in-a-vat [BIV]. 2. If I don't know that I am not a handless BIV, then I don't know that I have hands. Therefore, 3. I don't know that I have hands. The BIV argument is valid, its premises are intuitively compelling, and yet, its conclusion strikes us as a absurd. Something has to go, but what? Contextualists contend that an adequate solution to the skeptical problem must: (i) retain epistemic closure, (ii) explain the intuitive force of skeptical arguments by explaining why their premises initially seem so compelling, and (iii) account for the truth of our commonsense judgment that we do possess lots of ordinary knowledge. Contextualists maintain that the key to such a solution is recognizing that the semantic standards for 'knows' vary from context to context such that in skeptical contexts the skeptic's premises are true and so is her conclusion; but in ordinary contexts, her conclusion is false and so is her first premise. Despite its initial attractiveness, the contextualist solution comes at a significant cost, for contextualism has many counterintuitive results. After presenting the contextualist solution, I identify a number of these costs. I then offer a noncontextualist solution that meets the adequacy constraint identified above, while avoiding the costs associated with contextualism. Hence, one of the principal reasons offered for adopting a contextualist theory of knowledge -- its supposedly unique ability to adequately resolve the skeptical problem -- is undermined.
No categories
Contextualists often argue from examples where it seems true to say in one context that a person knows something but not true to say that in another context where skeptical hypotheses have been introduced. The skeptical hypotheses can be moderate, simply mentioning what might be the case or raising questions about what a person is certain of, or radical, where scenarios about demon worlds, brains in vats, The Matrix, etc., are introduced. I argue that the introduction of these skeptical hypotheses leads people to fallaciously infer that it is no longer true to say that the relevant person knows. I believe that that is a better explanation of the so-called intuition that the person does not know than the contextualists who claim that raising these skeptical hypotheses changes the standards that determine when it is true to say S knows that P. At the end I raise the possibility that contextualists might defend their view on pragmatic rather than skeptical grounds by arguing that the standards of evidence rise when more is at stake in a practical sense.
Philosophers have often noted that science displays an uncommon degree of consensus on beliefs among its practitioners. Yet consensus in the sciences is not a goal in itself. I consider cases of consensus on beliefs as concrete events. Consensus on beliefs is neither a sufficient nor a necessary condition for presuming that these beliefs constitute knowledge. A concrete consensus on a set of beliefs by a group of people at a given historical period may be explained by different factors according to various hypotheses. A particularly interesting hypothesis from an epistemic perspective is the knowledge hypothesis: shared knowledge explains a consensus on beliefs. If all the alternative hypotheses to the knowledge hypotheses are false or are not as good in explaining a concrete consensus on beliefs, the knowledge hypothesis is the best explanation of the consensus. If the knowledge hypothesis is best, a consensus becomes a plausible, though fallible, indicator of knowledge. I argue that if a consensus on beliefs is uncoerced, uniquely heterogeneous and large, the gap between the likelihood of the consensus given the knowledge hypothesis and its likelihoods given competing hypotheses tends to increase significantly. Consensus is a better indicator of knowledge than "success" or "human flourishing".
No categories
Skeptics claim that we know radically less than we think we do. For example, skeptics might claim that we have next to no knowledge of the past, the future, or other minds. Here we will consider the skeptical claim that we have next to no knowledge of the external world: the world of physical objects that we at least seem to perceive. One well-known argument in support of this claim appeals to the possibility of being a BIV: a brain in a vat. According to the BIV Hypothesis, you are a mere BIV without a normal body. This of course means, among other things, that you don't have hands. The nerve endings of your brain are stimulated in a manner so sophisticated that the perfect illusion of a normal life is generated. Let's distinguish between the..
Contextualism is supposed to explain why the following argument for skepticism seems plausible: (1) I don’t know that I am not a bodiless brain-in-a-vat (BIV); (2) If I know I have hands, then I know I am not a bodiless BIV; (3) Therefore, I do not know I have hands. Keith DeRose claims that (1) and (2) are “initially plausible.” I claim that (1) is initially plausible only because of an implicit argument that stands behind it; it is not intuitively plausible. The argument DeRose offers is based on the requirement of sensitivity, that is, on the idea that if you know something then you would not believe it if it were false. I criticize the sensitivity requirement thereby undercutting its support for (1) and the skeptical data that contextualism is meant to explain. While skepticism is not a plausible ground for contextualism, I argue that certain pragmatic considerations are. It’s plausible to think that to know something more evidence is required when more is at stake. The best way to handle skepticism is to criticize the arguments for it. We should not adopt contextualism as a means of accommodating skepticism even if there are other pragmatic reasons for being a contextualist about knowledge.
According to a typical skeptical hypothesis, the evidence of your senses has been massively deceptive. Venerable skeptical hypotheses include the hypotheses that you have been deceived by a powerful evil demon, that you are now having an incredibly detailed dream, and that you are a brain in a vat. It is obviously reasonable for you now to be confident that neither of the above hypotheses is true. Epistemologists have proposed many stories to explain why that is reasonable. One theory is that those hypotheses are inherently much less plausible than the hypothesis that your senses are basically reliable. Another theory is that you currently don’t believe any of those hypotheses, and that you need no justification to continue in that disbelief, given that your current beliefs cohere properly. A third theory is that —given that your senses are working properly—your sensory experiences themselves justify you in believing propositions such as the proposition that you have hands. Neo is given very good evidence that some skeptical hypothesis is true. He rightly becomes doubtful that his senses are or have been trustworthy. In fact, he becomes confident of a particular hypothesis: that AI’s created the Matrix, etc. But this is just one of many types of hypotheses that might account for his experiences. These types include.
No categories
I’m going to argue for a set of restricted skeptical results: roughly put, we don’t know that fire engines are red, we don’t know that we sometimes have pains in our lower backs, we don’t know that John Rawls was kind, and we don’t even know that we believe any of those truths. However, people unfamiliar with philosophy and cognitive science do know all those things. The skeptical argument is traditional in form: here’s a skeptical hypothesis; you can’t epistemically neutralize it, you have to be able to neutralize it to know P; so you don’t know P. But the skeptical hypotheses I plug into it are “real, live” scientific-philosophical hypotheses often thought to be actually true, unlike any of the outrageous traditional skeptical hypotheses (e.g., ‘You’re a brain in a vat’). So I call the resulting skepticism Live Skepticism. Notably, the Live Skeptic’s argument goes through even if we adopt the clever anti-skeptical fixes thought up in recent years such as reliabilism, relevant alternatives theory, contextualism, and the rejection of epistemic closure. Furthermore, the scope of Live Skepticism is bizarre: although we don’t know the simple facts noted above, many of us do know that there are black holes and other amazing facts.
Discussion of Bryan Frances, Live skeptical hypotheses
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