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Ideas of Peter Unger, by Text

[American, fl. 1975, Professor at New York University.]

1975 Ignorance: a Case for Scepticism
Intro p.1 No one knows anything, and no one is ever justified or reasonable
     Full Idea: I argue for the thesis that no one ever knows about anything, ...and that consequently no one is ever justified or at all reasonable in anything.
     From: Peter Unger (Ignorance: a Case for Scepticism [1975], Intro)
     A reaction: The premiss of his book seems to be that knowledge is assumed to require certainty, and is therefore impossible. Unger has helped push us to a more relaxed and fallibilist attitude to knowledge. 'No one is reasonable' is daft!
1.12 p.42 An evil scientist may give you a momentary life, with totally false memories
     Full Idea: The evil scientist might not only be deceiving you with his electrodes; maybe he has just created you with your ostensible memory beliefs and experiences, and for good measure he will immediately destroy you, so in the next moment you no longer exist.
     From: Peter Unger (Ignorance: a Case for Scepticism [1975], 1.12)
     A reaction: This is based on Russell's scepticism about memory (Idea 2792). Even this very train of thought may not exist, if the first half of it was implanted, rather than being developed by you. I cannot see how to dispute this possibility.
2.1 p.53 The meaning of 'know' does not change from courtroom to living room
     Full Idea: There is no reason to suppose that the meaning of 'know' changes from the courtroom to the living room and back again; no more than for supposing that 'vacuum' changes from the laboratory to the cannery.
     From: Peter Unger (Ignorance: a Case for Scepticism [1975], 2.1)
     A reaction: I disagree. Lots of words change their meaning (or reference) according to context. Flat, fast, tall, clever. She 'knows a lot' certainly requires a context. The bar of justification goes up and down, and 'knowledge' changes accordingly.
1979 There are no ordinary things
p.11 There are no objects with proper parts; there are only mereological simples
     Full Idea: Eliminativism is often associated with Unger, who defends 'mereological nihilism', that there are no composite objects (objects with proper parts); there are only mereological simples (with no proper parts). The nihilist denies statues and ships.
     From: report of Peter Unger (There are no ordinary things [1979]) by Ryan Wasserman - Material Constitution 4
     A reaction: The puzzle here is that he has a very clear notion of identity for the simples, but somehow bars combinations from having identity. So identity is simplicity? 'Complex identity' doesn't sound like an oxymoron. We're stuck if there are no simples.
p.13 Vague predicates lack application; there are no borderline cases; vague F is not F
     Full Idea: In a slogan, Unger's thesis is that all vague predicates lack application ('nihilism', says Williamson). Classical logic can be retained in its entirety. There are no borderline cases: for vague F, everything is not F; nothing is either F or borderline F.
     From: report of Peter Unger (There are no ordinary things [1979]) by R Keefe / P Smith - Intro: Theories of Vagueness 1
     A reaction: Vague F could be translated as 'I'm quite tempted to apply F', in which case Unger is right. This would go with Russell's view. Logic and reason need precise concepts. The only strategy with vagueness is to reason hypothetically.