I used to intensely dislike the phrase: ‘that’s an exception that proves the rule.’ Yet I’ve come to like it recently, if it’s read as: ‘that’s representative insofar as it’s a limit-case’. Limits are interesting, not for what’s outside them, but for what’s inside them.

The most difficult and controversial arguments I make against consensus positions in various topics are of the form: ‘you have taken an edge case that defines the boundary of the problem for an exemplar that represents its centre.’

Some are satisfied by objecting to a generalisation with an edge case, like ‘penguins are birds too!’, ‘I’ve got a [insert demographic friend] who thinks that’s funny!’, or even, non-constructive assertions such as ‘not all men!’ Such satisfaction is abductive incompetence.

This isn’t to say edge cases aren’t important, and it isn’t even to say that their transgressive potential to pop deductive bubbles should be ignored. Sometimes you need to say something like: ‘but what about intersex people?’ In such cases the exception can be usefully centred.

But deductive transgression is generally easier than abductive exploration/explanation. This is the computational difference between *exhibiting* an exception and *handling* it. The latter is most often harder than the former. Boolean quantifiers ignore these pragmatics entirely.