JoshuaZ comments on But Somebody Would Have Noticed - Less Wrong

36 Post author: Alicorn 04 May 2010 06:56PM

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Comment author: JoshuaZ 05 May 2010 01:23:49AM 4 points [-]

And note also that even Russell's paradox was not phrased originally in this way. His original phrasing as I understand it rested on taking the set of all sets A and then looking at the cardinality of that set's powerset P(A). Then we have |P(A)| > |A| but P(A) <= A so |P(A)| <= |A| which is a contradiction. This is essentially the same as Russell's paradox when one expands out the details (particularly, the details in the proof that in general a set has cardinality strictly less than its powerset).

Comment author: Sniffnoy 05 May 2010 01:36:14AM 1 point [-]

Ah, good point. I'd forgotten about that part. IIRC he first noted that and then expanded out the details to see where the problem was.