"But let us never forget, either, as all conventional history of philosophy conspires to make us forget, what the 'great thinkers' really are: proper objects, indeed, of pity, but even more, of horror."
David Stove's "What Is Wrong With Our Thoughts" is a critique of philosophy that I can only call epic.
The astute reader will of course find themselves objecting to Stove's notion that we should be catologuing every possible way to do philosophy wrong. It's not like there's some originally pure mode of thought, being tainted by only a small library of poisons. It's just that there are exponentially more possible crazy thoughts than sane thoughts, c.f. entropy.
But Stove's list of 39 different classic crazinesses applied to the number three is absolute pure epic gold. (Scroll down about halfway through if you want to jump there directly.)
I especially like #8: "There is an integer between two and four, but it is not three, and its true name and nature are not to be revealed."
In the OB post tautologies have to be empirically observed somehow, Eliezer writes about waking up one day and discovering all sorts of evidence that 2+2=3. This wouldn't be evidence that 2+2=3 in Peano arithmetic, it would be evidence that Peano arithmetic just doesn't apply for some reason. In my down-voted comment, I was just giving an example of how there can be different kinds of arithmetic if you are willing to be flexible about what arithmetic is. (If you are not willing to be flexible, then you are not willing to allow the observation that 2+2=3 as an observation about arithmetic, because this is not possibly true in standard arithmetic. Well, the observations are possible but you'd have to account for it as some kind of grand delusion.) My point is that 2+2=4 in Peano Arithmetic independent of observation, but observation tells you if Peano arithmetic applies or not.
Exactly.
It is worth emphasizing that to claim that "2+2=4 in Peano Arithmetic independent of observation" is not to claim that our knowledge of this fact about Peano Arithmetic is independent of observation. (The former claim is about our map of the territory; the latter is about our map of our map of the territory.)