Sunday, July 18, 2010

Thought of the Day

I've never understood the expression "the exception that proves the rule." Exceptions disprove rules.


Ron said...

I disagree. I had a debate a while back over moral realism with some atheists that went like this:

First I claimed that there is a universal principle against murder for example. Immediately of course the atheists brought up the police killing an armed suspect, a soldier fighting on the beaches of Normandy, etc. These are allegedly to be exceptions to the rule that disprove it but on the contrary these 'exceptions' prove the rule in that inherent in the idea of 'murder' is the idea of it being unjustified killing. So instead of these cases suggesting that murder isn't wrong as a rule, they in fact suggest the opposite since justification for the killing is built into them.

So, exceptions can often prove the rule in that many times they aren't really exceptions.

Ronan said...

It originally meant 'prove' in the sense of 'test', but has evolved into the current post-literate meaning.

JSA said...

For there to be an exception, there must be a rule. The very act of calling it an "exception" nods to the rule. It's like C.S. Lewis's response to the problem of evil, where he explicitly used the analogy of a ruler -- you can't call something crooked if you don't have a concept of straight.

Jim S. said...

Great. Three reasonable and mutually exclusive answers. Now I'm even more confused.

jacob longshore said...

You might check out this site:

According to it, the idea is that an exception highlights the existence of a rule by virtue of that rule's *absence*. Their example: "Entry is free on Sundays" leads us to infer that you have to pay on the other 6 days of the week; the exception demonstrates the rule.

This seems to me a very plausible explanation, and it makes more sense than any other that I've seen, but unfortunately I can't find any authoritative citations backing up the site. However, stronger support can be found here:

Ilíon said...

As Ronan indicates, to prove a thing, to "prove the rule" -- or to prove a math problem -- is to test the thing being proved against some standard. Thus, auto proving grounds are places where automobile designs are tested against (relatively) real-world conditions.

To prove a thing is evaluate whether it meets or conforms to the appropriate standard.

Ilíon said...

The meaning of "the exception that proves the rule" is this:
1) here is a rule;
2) here is an asserted exception to the rule;
Now we test purported exception against the rule; what is the result:
3) does the rule hold, such that the purported exception is not an exception, after all?
4) is the purported exception really an exception?
4a) how do we account for it in relation to the rule?
5) does the exception destroy the rule?