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Nisan comments on Gap in understanding of Logical Pinpointing - Less Wrong Discussion

6 Post author: Incorrect 12 November 2012 05:33PM

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Comment author: Nisan 12 November 2012 06:56:08PM 3 points [-]

Oh I see. The way I would say this is:

While the axiom schema of induction effectively quantifies over properties definable in PA, the second-order version quantifies over ALL properties, including those you can't even define in PA.