Radical Skepticism and its Responses
Can we ever know if we are not a brain-in-a-vat? Read this blog to know what popular responses to this question are.
The Radical Skepticism Paradox
Radical Skepticism is the belief that it is impossible to know anything at all about the world. Pritchard explains that instead of being viewed as a philosophical stance, in the contemporary debate, it has come to be taken as a challenge that a good theory or theorist of knowledge needs to overcome. This is what he calls the methodological function of radical skepticism. Additionally, a skeptic must not be thought of as a person, but as one’s own intellectual conscience.
Components
The two main components of skeptical arguments are:
- We cannot know that we are not the victims of a skeptical hypothesis. A skeptical hypothesis refers to a circumstance in which a person is radically deceived about their experience of the world, but their experience is the same as it would have been had they not been radically deceived. For example — the plot of The Matrix. The problem that such a hypothesis poses is that we cannot know that we are not the victims of it.
- If we cannot deny the skeptical hypothesis, we do not/cannot know anything at all. In any particular instance, how can a person be sure if they are really experiencing what they think they are experiencing of they do not know, for sure, that they are not the victims of the skeptical hypothesis? Thus, if the possibility of skeptical hypotheses cannot be ruled out, we do not seem to be able to know anything at all.
Argument
Pritchard explains that the skeptical argument can be expressed as given below:
Premise 1: We are unable to know the denials of skeptical hypotheses.
Premise 2: If we are unable to know the denials of skeptical hypotheses, then we are unable to know anything of substance about the world.
Conclusion: We are unable to know anything of substance about the world.
This is a valid argument. But it is also a paradoxical one. P1 and P2 seem to be intuitive, yet they entail an absurd conclusion which seems to be counter-intuitive.
One might attempt to refute the argument by attacking P2. The epistemic standards imposed by the skeptical hypotheses are highly restrictive, and one might say that they can be rejected in favor of less restrictive, intuitively correct ones.
But there are additional principles and positions that need to be considered while attempting to support/refute the skeptical argument. These will be explained in the rest of the blog.
The Closure Principle
Pritchard gives the following description of the closure principle:
If I know one proposition, and I know that this proposition entails a second proposition, then I know the second proposition as well.
Using the closure principle, the truth of P2 might be made to seem uncontentious.
It can be understood through the following example. I am brewing coffee in my kitchen at the moment. If I am doing that, then I cannot be in college attending a lecture. Thus, I know that I am not in college attending a lecture. It does not seem that the closure principle is explaining anything remarkable at all. If I know where I am and what I am doing, then I know that I am not a brain-in-a-vat. The skeptics reply to this is to point to P1, and state that one does not know whether or not one is a brain-in-a-vat. Thus, one also does not one where one is or what one is doing.
The skeptics use the closure principle to make the reliability of everyday propositions contingent upon the knowledge of the refutation of the skeptical hypotheses. Such an argument (based on the closure principle) even seems intuitive and adhering to commonly accepted epistemic principles. It makes the skeptical conclusion seem unavoidable.
Skepticism and Closure
One might attempt to refute the closure principle. But how can one know a proposition but not know another proposition that is entailed by the first one? Thus, an attempt to deny it seems to be stem out of desperation to nullify its value to the skeptics, since its use seems to be unproblematic in all other (non-skeptic) circumstances. Two attempts made by fallibility (people who believe that empirical propositions can be accepted even if they cannot be proved with certainty) to refute the closure principle are:
- Labelling skeptical hypotheses as ‘irrelevant’: Fallibilists claim that one needs only rule out relevant (and not all) possibilities of error to be able to know something. They say that the closure principle asks for the rejection of far-fetched and irrelevant skeptical hypotheses, and thus, needs to be done away with. But this argument is not convincing as the closure principle is completely compatible with the fallibilistic notion of only ruling out relevant possibilities of error (as the radical skepticism hypotheses is incompatible, and thus relevant for rejection for a refutation of the hypotheses).
- Using the sensitivity principle: Pritchard describe the sensitivity principle in the following way:
“If an agent knows a proposition, then that agent’s true belief in that proposition must be sensitive in the sense that, had that proposition been false, she would not have believed it.”
As per this principle, everyday beliefs are sensitive to truth. For example: I would not believe that I am writing this blog had I instead been asleep. However, my belief that I am not a brain-in-a-vat is not truth-sensitive, because even if I were actually a brain-in-a-vat, I could be ‘fed’/made to believe that I am not.
Thus, a sensitive belief would change as facts do, preventing one from developing a false belief, whereas this is not the case for an insensitive belief (like a skeptical belief). Skeptical hypotheses are explicitly characterized as leading to beliefs that whose truth/falsity is insensitive.
Accepting the sensitivity principle (and thus, denying the closure principle) would allow one to hold a number of propositions as knowledge. The former is, not unlike latter, quite intuitive.
Mooreanism
Proposed by G.E. Moore, this response aims to use the closure principle to refute skepticism. By claiming that we know a number of proposition that entail the falsity of the skeptical hypotheses, the latter may be refuted. We have knowledge of mundane propositions (for example — I am writing this blog. I can’t both be writing this blog and be floating in a vat full of nutrients. Therefore, I am not a brain-in-a-vat).
However, this attempt to use the closure principle to refute skepticism leads to irresolution. We commit the fallacy of begging the question when we begin our argument by claiming that we know something (like I claimed to know that I am writing this blog). This use of an instance of knowledge to refute skepticism is fallacious and problematic since skepticism’s central claim is that we cannot know.
One central claim of the skeptical hypotheses is that we cannot know the denial of such a hypotheses. Thus, people with a Moorean stance need to explain (rather than just assume) how they come to know something. And this, as we know, is a very difficult task.
To defend Mooreanism, one can adopt the direct realist stance. As per this position, we directly experience the world. And in the cases of skeptical hypotheses, as one does not directly experience the world, these cases can be distinguished from the real ones, and thus be rejected as they are unreal. These two categories of cases are not the same, even if one is unable to tell the difference between them.
If this is accepted, then Mooreanism would be strongly supported. The direct realist claim does not seem to dispute the skeptic’s claim at our inability to tell the difference between cases of deception and non-deception, rather it claims that just because we cannot tell the difference between them, we should not claim that we do not directly experience the world in non-deceptive cases.
But the problem is that one might be unable to tell apart the deceptive and non-deceptive cases. The following principle might be applied to help with this:
The Safety Principle
The safety principle intends to capture the idea that knowledge cannot depend on luck.
Pritchard describes the safety principle in the following way:
If an agent knows a proposition, then that agent’s true belief in that proposition must be safe in the sense that it couldn’t have easily been false (alternatively: were the agent to continue believing that proposition in similar circumstances, then the belief would almost always still be true).
So even though one may not have any solid reason to refute the brain-in-a-vat hypothesis (as one would be unable to tell the difference), as long as one’s experiences are normal and the same as what one takes them to be, one’s true belief that one is not a brain-in-a-vat would not be unsafe.
If one accepts this principle, the need to refute the closure principle vanishes.
It is important to note that Mooreanism is a form of epistemic externalism, as it permits the accumulation of knowledge without first denying successfully the skeptical hypotheses.
Mooreanism faces a number of objections and criticisms. A decisive one is that it appear to try to sidestep the skeptical issue. Pritchard says:
The skeptic is therefore claiming that whatever circumstances we find ourselves in, we are unable to know very much (including that we are not the victim of a skeptical hypotheses); if this is right, it follows that we can assume anything we like about what circumstances we are in without dodging the skeptical challenge.
Contextualism
As per this view, the skeptical challenge can be solved if one understands knowledge to be a highly context-sensitive notion. For example — ‘flat’ surface for scientist and for common people means different things. In the same way, ‘know’ for skeptics is used in a more demanding way than it is by the everyday standards of other people. For one to have knowledge through everyday standards, one just needs to eliminate normal, mundane and non-skeptical possibilities of error. For one to have knowledge through skeptical standards, on the other hand, there is a requirement to rule out even far-fetched skeptical hypotheses.
Thus, one can know a lot through lenient everyday standards of knowledge, but nothing at all through skeptic’s exacting ones. Also, there is no need for a denial of the closure principle so long as we use one context at a time. Also, as per this position, skeptics are being credited with having a valid argument as per their own standards.
Even though this seems like a tidy solution to the problem, it has several issues that surface on closer inspection. For one, the analogy of the ‘flat surface’ is problematic. Nothing is ever perfectly flat. But still we use that word to describe surfaces. This means we talk loosely when we speak such things. Similarly, we do not really know anything, as all possibilities of error (including skeptical ones) cannot be ruled out. Thus, when we are using the word know, we are using it very loosely. The second objection is that it needn’t be the case that a skeptic is considered as having high standards for knowledge. What they are claiming is that we have no grounds at all to reject skeptical hypotheses, and not whether our grounds are good or bad. Thus, they do not seem to be appealing to a difficult epistemic standard; the skeptical challenge persists for any chosen epistemic standard — low or high. And if we apply the closure principle here, it would mean that we lack everyday knowledge also.
It seems less problematic to accept the position of Mooreanism (which claims as possible the knowledge of the denial of the skeptical hypotheses) instead of going for the position of contextualism (which claims as possible the knowledge of both — the denial of skepticism and the notion of knowledge as a highly context-sensitive notion, which supports skepticism).
Conclusion
All of the response against skepticism discussed in this blog have their own challenges and flaws. There hasn’t been an uncontested refutation of the skeptical hypotheses yet, and this tasks seems to be extremely challenging, if not impossible.
