…are those which, if true, would make argument impossible. If there were to be a litmus test for a functioning mind, this would be it: if you make an argument which, if valid, proves that argument is impossible, FAIL!
Examples are alarmingly common. Short and sweet:
There is no truth. I am all that is.
Free will does not exist (in the words of Lucy, then why are you telling me?). Truth is unknowable. We can’t know if we are sleeping or awake.
Most of the more long-winded self-eradicating arguments are really based on nothing more sophisticated than these. Often, there’s an implied nod and a wink in there as well – oh, sure, I know that if I claim their is no truth (in however roundabout a way that claim is made), there’s no point to this (or any other) argument, but, hey, we really know that what I mean is that there’s no point to THEIR arguments, you know, the ones that are mean and would lead one to conclude that MY world view is, well, STUPID.
It’s vanishingly rare to see that level of clarity*.
So, we hereby declare: if your argument either leads to or is premised on the impossibility or meaninglessness of argument, then – shut up. Go home. Rethink your decision-making paradigm.
* I’ve heard 2nd hand that the recently deceased (2007) philosopher Richard Rorty comes around eventually to the concept of ‘irony’ as the label for the state one reaches when one rejects all analytical (truth-based?) metaphysics yet still feels compelled (by what?) to care about stuff. This sounds indistinguishable from some blend of despair and fantasy (I will disavow knowledge & truth, but assert nonetheless a deep concern for people and society, even though I recognize that they don’t even exist in any coherent manner), but, hey, haven’t read the dude (yet).
Stack of books on the floor is now well into double digits, and the need to read a lot more history is greater than the need to digest yet one more ‘philosopher’, sooo – I’ll comment on Rorty in a year or two.