Proving it

“Explain this, then; the phrase ‘it’s the exception that proves the rule’. How can the exception show that the rule is true?”

Not for the first time, there was silence in the theatre.

“It doesn’t make any sense,” said one of the juniors. “If there is an exception, the rule cannot be true.”

“It makes perfect sense,” I replied, “though I did try to mislead you just a little.”

“I can’t see how it can be correct.”

“But it is, and you know that it is,” I said. “You just don’t know that you know.”

Another silence.

“Do any of you like whiskey?” I asked. There was a murmur of assent. 

“I don’t, but haven’t you looked at what it says on the label? Beyond the name and all the usual guff.”

Clearly, they hadn’t, or if they had it hadn’t registered.

“OK, do any of you make bread with yeast then?” There was another murmur, alas only from the girls.

“And after you’ve mixed it all up, what do you do next?”

“I leave it to prove,” answered one of the girls.

“Exactly. So what are you doing?”

“Waiting to see that the dough rises. I usually put it in the airing cupboard.”

“Yes,” I replied, “and when it rises, what does that mean?”

There are times when you have to drag answers kicking and screaming out of people. It can be bloody.

“It means that the yeast is healthy, that it’s alive.”

“So, could you give me another word instead of ‘prove’ for what you are doing?”

“I suppose you’re testing the yeast.”

“Say that word again, please,” I asked, “slowly.”

“Testing.”

At last; but why is it so often the nurses who can work it out?

“So, the word ‘prove’ actually means ‘to test’ then?”

“Yes, but I though it meant it showing something was true.”

“It’s an example of how words can change their meanings over time,” I said. “Originally, it meant ‘to test’, but now we think of is as ‘showing something is true’.

“So, go back to ‘it’s the exception that proves the rule’ and replace ‘proves’ with ‘tests’ and it makes sense, doesn’t it?”

“Ah, I see. But what about the whiskey? What were you on about there?”

“It used to say on the label something like ‘40° Proof Spirit’,” I said, “meaning that it had been tested and found to have the correct amount of alcohol.

“But now, can anyone tell me how they used to test whiskey?”