pretty much this entire post: http://lesswrong.com/lw/ezu/stuff_that_makes_stuff_happen/

Quote a specific line where Eliezer's words suggest that 'real' for him means simply 'important' or 'interesting' or 'observable.'

And I disagree about taboos bottoming out: eventually you should reduce words to things that are not words, such as images and equations.

Why? If you understand my words in terms of their relationship to other words, what added value is gained in reducing to an act of mere gesturing? (Also, images and equations are still symbols, so they're clearly not where ostension should bottom out; the meanings of images and equations require bottoming out, on your view, in something that is not itself meaningful. A better example might be a sense-datum. See Russell's The Relation of Sense-data to Physics.)

"a negative number is one for wich there exists a number wich is not itself negative that when added to it yelds zero"

Sorry, I'm not talking about negative numbers like -5. I'm talking about negated propositions, like "2 plus 2 is not equal to five," or "fire is not cold." I don't think negative numbers are conceptually basic, but I think that negation is.