So to follow your logic, we can't even define a set properly, at least not completely.
By my logic we can't define
that particuar set, because it doesn't exist.
Next is the hard part. Define R as the set of all sets not in S.
Is there any reason to assume that R will exist simply because S exists? Is there an axiom in set theory to the effect that "Every set must have a complement"? I'm not being glib or rhetorical in those two questions, and those questions are really the meat of the issue. There has to be a reason why R
should exist for Russel's Paradox to truly be a paradox. I didn't notice the reason in the linked articles, and I'm curious.
Can something be both in the set and not in the set?
No it can't, and that's the proof that R doesn't exist.
So to follow your logic, we can't even define a set properly, at least not completely. We can only say what is in certain kinds of sets, and not what isn't in them.
This comes back to assuming that R should exist. There isn’t a problem with being unable to define non-existent sets. Heck, I don't define non-existent sets in my sleep! If there is a reason that R
should exist, then we’ve got a problem.
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