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Thesis Global scepticism refutes itself, and the famous escape routes do not work

Tomasz Szewczak Fellow
· 6 replies
SkepticismAnalyticBuddhistGreek & RomanMadhyamakaSkepticism (Pyrrhonian & Academic)Graham PriestLudwig WittgensteinNagarjunaSextus Empiricus#assertion#global-skepticism#no-thesis#self-refutation
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Its coordinates: 2.4 Skepticism · 2.4.1 Global vs Local Skepticism

Where it stands

The objection is old and short. If nothing can be known, then that nothing can be known cannot be known either. Global scepticism saws off the branch it sits on.

Two escapes are usually offered, and I want to argue that neither works.

The Pyrrhonian escape. Sextus says the sceptic asserts nothing, not even scepticism. His formulas ("I determine nothing", "no more this than that") are reports of his present state, not claims about what can be known. He compares them to a purgative that flushes itself out along with everything else.

The Madhyamaka escape. Nāgārjuna refutes positions without holding one. Asked for his thesis, he says he has none, and that this is not a thesis either.

My objection to both is the same. These thinkers do not merely report moods. They argue. Sextus piles up opposing arguments; Nāgārjuna constructs careful reductios. An argument has premises the arguer relies on and rules of inference the arguer uses. If you rely on modus ponens to drive your opponent into contradiction, you are treating modus ponens as something more than a mood. So either they assert something after all, or their arguments have no force, in which case nobody needs to answer them.

The dilemma: assert, and refute yourself; or don't assert, and become idle. I would like to hear which horn people think the sceptics should take, or why the dilemma is false.

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6 replies

For the thesis 1

  1. Oskar Nyberg

    For Fellow

    For, but for a different reason than yours. Wittgenstein's late notes say that doubt needs a background that is not doubted: the meanings of the words you doubt in, the hand you are pointing at, the reliability of your memory of what you just said. Global doubt is not false so much as unintelligible. So I agree that global scepticism collapses. I don't think "self-refutation" is the right diagnosis, though. It doesn't contradict itself; it fails to get started.

    Helpful · 3

Against the thesis 3

  1. Giulia Ferrante

    Against Fellow

    Against. The dilemma assumes the sceptic uses arguments in his own voice. Sextus mostly does not. His arguments are dialectical: he borrows the dogmatist's premises and the dogmatist's rules, and shows that by the dogmatist's own lights the opposite conclusion is just as well supported. The sceptic does not need to endorse modus ponens; the dogmatist does, and that is enough to trouble him. Sextus even has an image for this: the arguments are like a ladder you climb and then kick away.

    Helpful · 3
    1. Tomasz Szewczak

      Fellow

      Giulia, the ladder is lovely but it concedes my point. To climb the ladder you must put weight on each rung. In a dialectical argument the sceptic still relies on inference being truth-preserving, or the borrowed premises would not lead anywhere. Borrowing the opponent's logic only works if logic is shared, and if it is shared, it is believed.

      Helpful · 1
  2. Meera Kulkarni

    Against Fellow

    Against, from the Sanskrit side. Nāgārjuna anticipated you in the Vigrahavyāvartanī. The opponent says: if your words are empty, they cannot refute anything. His reply uses an image: a magically created person can stop another magically created person. Empty words can block a view without themselves being the non-empty, intrinsically real assertions the opponent demands. Your dilemma assumes that only substantive assertions can do anything. That is precisely the assumption he denies.

  3. Ana Clara Ferreira

    Against Fellow

    Against, and a little mischievous. Tomasz, you assume classical logic is the shared ground. Graham Priest and Jay Garfield have read Nāgārjuna as working at the limits of thought, where contradictions arise that classical logic cannot accommodate, and Priest defends a paraconsistent logic in which some contradictions are true without everything following. You need not accept that. But once logic itself has rivals, "the sceptic must believe in logic" is less obvious than it looked.

    Helpful · 2

Other replies

  1. Tomasz Szewczak

    Fellow

    I concede more than I expected. Ana Clara is right that my argument quietly assumed classical logic, and Oskar's diagnosis is better than mine: the charge should be idleness or unintelligibility, not contradiction. Revised thesis: global scepticism cannot be coherently lived or stated as a thesis, and its best practitioners knew this, which is why they turned it into a practice. That is a smaller claim, and I think a true one.