Questions: Responses to External World Skepticism

Question 1

G.E. Moore's 'here is a hand' argument responds to external world skepticism by:

• A. Providing empirical evidence that brains-in-vats could not produce the specific sensations Moore experiences
• B. Showing that the skeptical argument is formally invalid — its premises don't logically entail the conclusion
• C. Reversing the direction of the skeptical argument: using certainty about ordinary things to discharge the skeptical hypothesis rather than directly refuting it
• D. Accepting that we don't know ordinary things, but arguing this doesn't matter for practical life

Answer: (C)

Moore doesn't try to prove the BIV scenario is impossible, nor does he attack the logical structure of the argument. Instead, he runs the closure principle in the opposite direction: I know I have hands (more certain than any philosophical premise) → knowing I have hands entails knowing I'm not a BIV → therefore I know I'm not a BIV. The sophistication is recognizing that we are more justified in believing mundane facts than in any philosophical chain that would lead us to doubt them. Options A and B describe direct refutation of the skeptical premises, which Moore doesn't attempt.

Question 2

A philosopher argues: 'Skepticism proves that ordinary claims like "I know it is raining" are false, since we cannot rule out skeptical scenarios.' A contextualist would respond by saying:

• A. The philosopher is right — ordinary knowledge claims are false, which is why we should avoid asserting we know anything
• B. The philosopher is using a stricter standard for 'know' than is operative in ordinary contexts — at normal standards, knowing it is raining requires only ruling out relevant realistic alternatives, not BIV scenarios
• C. The philosopher's argument is unsound because premise (1) — that we cannot rule out BIV — is false
• D. The philosopher confuses knowledge with certainty; knowledge only requires justified true belief, not ruling out all possible errors

Answer: (B)

Contextualism doesn't deny the skeptic's conclusion within the philosophical context — at seminar-level standards, you indeed don't know. What contextualism denies is that these standards apply everywhere. In ordinary contexts, knowing it is raining requires ruling out relevant real-world alternatives, not BIV scenarios. The skeptic has artificially elevated the standards, making their conclusion true-but-contextually-irrelevant. Option C describes the dogmatist response. The common misconception is thinking contextualists claim the skeptic is simply wrong — they claim the skeptic is right at those standards, but irrelevant.

Question 3

Most serious philosophical response to external world skepticism should ultimately show that the BIV or evil-demon scenario is very difficult or incoherent, since leaving it open concedes too much ground to the skeptic.

• T. True
• F. False

Answer: False

This is precisely what Moore, dogmatists, and contextualists all reject in different ways. Moore never shows BIV is impossible — he uses ordinary certainties to discharge the hypothesis via the Moorean shift. Dogmatists argue we don't need to refute skeptical hypotheses before perception justifies belief. Contextualists say the hypothesis is only relevant at artificially elevated standards. Only the abductive response tries to argue positively against BIV (as an inferior explanation). Demanding direct refutation of BIV is itself a philosophical assumption the skeptic wants us to grant, and each response challenges it differently.

Question 4

Dogmatism (in Pryor's sense) holds that perceptual experience provides immediate, prima facie justification for perceptual beliefs without first requiring us to rule out skeptical hypotheses.

• T. True
• F. False

Answer: True

This is the defining claim of dogmatism. The skeptic assumes the justificatory order runs: (1) first establish you're not a BIV, then (2) trust your perceptions. Dogmatists reject this order entirely — perception is the starting point of justification, not a conclusion to be earned through prior philosophical work. 'Prima facie' means the justification is defeasible if you learn you actually are in a skeptical scenario, but it doesn't need to be antecedently discharged. This directly attacks the skeptic's implicit premise that external-world assumptions must be justified before perceptual evidence is admitted.

Question 5

Explain the 'Moorean shift' and how it exploits epistemic closure. Why does Moore think 'I know I have hands' is a more secure starting point than the philosophical premises the skeptic builds from?

Model answer: The Moorean shift uses epistemic closure — if you know P and know P entails Q, then you know Q — but runs it opposite to the skeptic. The skeptic argues: can't rule out BIV → don't know I have hands. Moore argues: I know I have hands → knowing this entails knowing I'm not a BIV → so I know I'm not a BIV. Both use closure, but they start from different premises. Moore's insight is about relative certainty: 'I have hands' is more secure — more certain, better supported — than any chain of philosophical argument that would undermine it. If an argument leads to 'you don't have hands,' the right response is to reject one of its premises.

Moore's move looks naive but is sophisticated: it forces the skeptic to explain why their abstract philosophical premise should outweigh concrete perceptual certainty. The burden isn't always on the ordinary believer to defeat skeptical scenarios — sometimes the skeptic must justify why their premises deserve more credence than the commonsense beliefs they threaten.