Logically, when I think about p unless q
I want to say that it is equivalent to q -> ~p
, but the only equivalence is ~q -> p
. I verified by truth table that my intuition is wrong.
An example of why I want to think this way: I will go golfing tomorrow unless it rains
in my mind is equivalent to If it rains tomorrow then I will not go golfing
.
Is this basically a similar case to how when we state implications in general English that we imply the biconditional, even though it is a illogic thing to do?
How can I think about this when telling myself not to follow my intuition in this case? Is the reason that q -> ~p
is wrong that p unless q
doesn't say anything about what will happen if q
is true
?