Showing posts from December, 2021

On the value of double negatives (series: notes to myself)

I grew up as a classic logician. "Classic", not as in "typical", but as in "logic based on the classic assumptions of the principle of  bivalence  and the law of excluded middle ".  Everything used to be either true or false. If something was not true, then it had to be false, and of course vice-versa: p or not p , nothing else, with not-not p just being equal to p .  Disproving not p was equivalent to proving that p . If you think of it, it is quite a smart but  strange way of reasoning . Like proving that you are healthy by assuming that you are sick, then running a whole series of deductions, showing that they all lead, inevitably and necessarily, to impossible conclusions, and hence inferring that the premise must be false, thus finally concluding that, since you are not sick, you must be healthy after all. The trouble is that you still have no idea about how or in what sense you may be healthy. For related reasons, when I was young, I was not fond