Posted by Neal on November 15, 2013
“Rocco was doing it again today,” Adam told Doug at supper one night. His classmate Rocco has a habit of making contrarian claims, seemingly just for the purpose of arguing about them. “He was saying that Jews can be atheists.”
Maybe Rocco had some kind of idea that an atheist Jew would be something like a fasting carnivore, or a celibate homosexual (or heterosexual or bisexual), and hadn’t quite grasped the concept of criterial definitions. Or maybe he was thinking of Jew in a more cultural sense, like I just read about in this Wikipedia article. Whatever he had in mind, Doug and Adam weren’t buying it.
Adam tried to explain Rocco’s argument, not very satisfactorily, but that was because of the material he had to work with. He and Doug were laughing as they tried to dissect Rocco’s reasoning.
“You’re a Jew,” Doug said, “if and only if you believe in God!”
Well, you can’t say “if and only if” to a semanticist and expect it to pass unexamined. “So … Muslims are Jews?” I asked.
“No, Dad,” Doug explained. He then summarized for me the concept of only if, concluding, “You’ve out-literaled yourself!”
Later on, I drew a truth table for if and one for only if, and showed them to Doug. He found that, after all, he and I agreed about the meaning of only if. So what’s the difference between only if and if and only if, I asked.
“I don’t think there is one,” Doug said.
I drew up the table for if and only if, and Doug understood it, but in his opinion, in ordinary conversation, if and only if was just an emphatic way of saying “only if”.
“I’m with Doug on this one,” my wife offered. In a casual, dinner-table conversation, I shouldn’t have taken Doug’s if and only if in this technical sense.
Technical sense? This was my first inkling that there was more than one sense!
This weakening of if and only if to mean just only if is an interesting opposite to a pragmatic effect that Mike Geis and Arnold Zwicky named conditional perfection. Here’s the canonical example:
“I’ll give you $5 if you mow the lawn” taken to mean “I’ll give you $5 if and only if you mow the lawn.”
Now, in the opposite direction, we have
“You’re a Jew if and only if you believe in God” to mean “You’re a Jew only if you believe in God.”
I’m not totally convinced it’s real yet, though. I checked the spoken segment of COCA for if and only if and got a measly three hits. For what it’s worth, they all seem to have been used in the technical sense:
- Republicans in the house are embarking on their own effort, promising to cut spending and raise the debt ceiling if and only if both Houses of Congress vote for a balanced budget amendment in the coming days.
- We simply should never have been in the business of saying to a 16-year-old girl,’ If and only if you have a child out of wedlock, we’ll send you a check in the mail.’
- we may have now a normative principle that that action is legitimate if and only if it proceeds on this model through the U.N.
What do you think? Have you used, or heard others use, if and only if to mean only if?