Usage of "if and only if" as a nontechnical term

The phrase "if and only if" (iff) is commonly used in the field of mathematics (⇔) and computer programming, as a conditional expression in classical (Boolean) logic.

Within that scope, it might not mean the same as a simple "if:"

If it rains, I will get wet.

I will get wet if it rains, but, there are numerous ways to get wet.

I will get wet, if and only if it rains.

Only rain, exclusively, can make me wet.

Do these distinctions apply in this way (example above), outside of the aforementioned domain?

Solution 1:

When you say "if and only if" in regular conversation, you are taking the mathematical construction and applying it to a general life situation. So you can say "I will get wet if and only if it rains" and mean that:

If it is raining, I am wet.

AND:

If I am wet, it is raining.

(If either condition is met, the other is also met.)

Solution 2:

Yes, it does work (though it sounds a little technical) in common language because by saying:

I will get wet if and only if it rains.

you are saying both

I will get wet if it rains.

(meaning that if it rains there is no chance I will not be wet) and

I will get wet only if it rains.

(there is no way I will get wet unless it rains).