>>14395100 many logicians seem to think that way
https://en.wikipedia.org/wiki/Relevance_logic >>14395128 >That statement can only be falsemeaning P -> Q = F
>There is a simple language-reasoning way to make sense of it: if I claim "when P is true, Q is true", no causal relationship is implied between the two; only that whenever P is true, Q is also trueMeaning if P is false the claim P -> Q is true regardless because it only refers to the case where P is true?
Using better versions of the examples here
>>14394949If all niggers commit crimes, and niggers will indeed be sent to Africa, P = T and Q = T, P -> Q = T. The promise/conditional is true.
If all niggers commit crimes, but they won't be sent to Africa, P = T and Q = F, P -> Q = F. The promise is false.
If not all niggers commit crimes, and niggers will be sent to Africa, P = F and Q = T, P -> Q = T because the promise is still (or could still be) true anyway.
If not all niggers commit crimes, and niggers will not be sent to Africa, P = F and Q = F, P -> Q = T because the promise (which is explicit that it's only talking about when P = T) is still true anyway.
>If all weebs like moe, then all weebs like shonen.The promise/conditional is: When (all weebs like moe) is true, (all weebs like shonen) is true.
When P is F, whatever Q is will say nothing about the relation P -> Q.
This model seems to work well with future propositions, what about present propositions?
>If anon was born in Boston, then anon is american. In your model this is equivalent to: When (anon was born in Boston) is true, (anon is american) is true.
For P = T it's trivial. For P = F, whether Q is T or F, it cannot prove or disprove the compound proposition (P -> Q) is T or F.
I
have
reached
enlightment.
But wait, why is P -> Q always T instead of always F (or just undefined) when P = F? Why assume it's T instead of F if, when P = F, nothing can be said about P -> Q?
