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AIBU?

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Original poster

AIBU to not understand how the exception proves the rule?

32 replies

J2Od · 11/03/2026 08:00

Please help me understand how the exception is supposed to prove the rule.

OP posts:
Lougle · 11/03/2026 08:28

The exception isn't 'when it goes wrong'. It's a 'but in these circumstances the rule doesn't apply'. So the fact that there are circumstances where the rule doesn't apply means that the rule is true in every other cicumstance.

ParmaVioletTea · 11/03/2026 08:28

J2Od · 11/03/2026 08:00

Please help me understand how the exception is supposed to prove the rule.

In this adage, “prove” means “test” not “offers evidence.”

So “the exception tests the rule.”

WhatAMarvelousTune · 11/03/2026 08:17

@Agixparking example, and @InfoSecInTheCityare right.
But people often misuse this saying - I’d say the black swan example is an example of it being misused. The existence of a black swan is not “the exception that proves the rule”. It actually disproves the “rule” that swans are white. Saying “free parking on weekends” does show the existence of the rule that parking is not free during the week, and is therefore the exception that proves the rule.

TulipsLilacs · 11/03/2026 08:14

That it's an exception proves that there's a rule.

InfoSecInTheCity · 11/03/2026 08:07

If ypu provide an exception then the implication is that a rule does exist, so if a sign says ‘no parking during 7am and 9am’ then the implication is that the rule is you can park there at all other times. ‘Guidedogs only’ implies a rule that no other animals allowed and so on.

SoftandQuiet · 11/03/2026 08:04

I think it means, for example, if you let one person wear trainers (against the rules) then more people will do it and then the whole school looks less smart (proves why they had this rule)

Agix · 11/03/2026 08:04

That there is a deviation from the rule proves the rule exists.

I.e, "a black swan" shows us that the general rule is that swans are white. A sign that says "No parking on Sundays" shows the rule that parking is mostly allowed (on all other days).

In other words, the reason the exception stands out and you feel the need to point it out is proof the rule exists in general.

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