No claim can be about everything, since "everything" would have to include "the set of all things that does not include this claim," which would violate the definition.
this sentence is about the set of all things that do not include this sentence, and this sentence.
see? that paradox you imagine doesn't translate, because "including" and "being about" aren't the same. even rewording it "this sentence is about the set of all sentences not about this sentence and also about itself" doesn't work, because being about something isn't transitive.
consider:
There is a sentence about this sentence.
That sentence is about the next sentence.
Two sentences ago, there was a sentence about this sentence and itself, and the sentence after it was about the same two sentences, and not about itself at all; but this sentence is a run-on and is about all three.
Discussion (4)
this sentence is about the set of all things that do not include this sentence, and this sentence.
see? that paradox you imagine doesn't translate, because "including" and "being about" aren't the same. even rewording it "this sentence is about the set of all sentences not about this sentence and also about itself" doesn't work, because being about something isn't transitive.
consider:
There is a sentence about this sentence.
That sentence is about the next sentence.
Two sentences ago, there was a sentence about this sentence and itself, and the sentence after it was about the same two sentences, and not about itself at all; but this sentence is a run-on and is about all three.
Claims inspired by this comment
A "paradox" is unsolveable, & is likely to give you a Headache.yes -- except that the paradox doesn't work this way.
All righty, then....
http://tinyurl.com/2pu4mm
And BTW, thanks for educating me about Russell's Paradox!