Not a formal Logician, but I like it, here?s my answer:
... If A not B then AB ...
To negate, the proponents recognize each other presence, and assimilate...
Regards>FILIPE DE ALBUQUERQUE
Your answer to what? This is a question about formal logic, because it is in formal logic that a false proposition implies any proposition. So how can an answer not have anything to do with formal logic?
Your answer to what? This is a question about formal logic, because it is in formal logic that a false proposition implies any proposition. So how can an answer not have anything to do with formal logic?
Sorry, I was referring to myself, i did not study Logic, so I am stating only an informal opinion...but I would like to know what you or someone else think of it.
Sorry, I was referring to myself, i did not study Logic, so I am stating only an informal opinion...but I would like to know what you or someone else think of it.
Regards>FILIPE DE ALBUQUERQUE
This is not a matter of opinion. It is a matter of formal logic.
Your answer to what? This is a question about formal logic, because it is in formal logic that a false proposition implies any proposition. So how can an answer not have anything to do with formal logic?
Doesn't that rely on Disjunctive Syllogism or Reductio Ad Absurdum?
Sorry, I don't know what you are getting at. Could you be more explicit?
That's the only proof I know of where a false proposition (and true) implies an arbitrary proposition Q, which relies on DS. DS doesn't "rely" on anything, because it's just an inference rule of the form {P∨Q, ?Q ⇒ P}. The only sense I can tell in which it "relies" on anything is that you need those two propositions to infer using DS. The same goes with RAA.
That's the only proof I know of where a false proposition (and true) implies an arbitrary proposition Q, which relies on DS. DS doesn't "rely" on anything, because it's just an inference rule of the form {P∨Q, ?Q ⇒ P}. The only sense I can tell in which it "relies" on anything is that you need those two propositions to infer using DS. The same goes with RAA.
I guess I don't understand what you mean by "relies". Do you mean that F>X implies DS or RAA? How?
Doesn't that rely on Disjunctive Syllogism or Reductio Ad Absurdum?
No it does not. Logical implication is defined in a way such that it directly follows from the definition. With the possible worlds' approach it is defined something like this:
[INDENT]P implies Q iff there is no possible world where it is not the case that Q and it is the case that P.
[/INDENT]Obviously if there is no possible world where P is the case, then there is no possible world where P is the case and Q is not the case.
No it does not. Logical implication is defined in a way such that it directly follows from the definition. With the possible worlds' approach it is defined something like this:
[INDENT]P implies Q iff there is no possible world where it is not the case that Q and it is the case that P.
[/INDENT]Obviously if there is no possible world where P is the case, then there is no possible world where P is the case and Q is not the case.
Right. And then the other lines on the truth-table have to conform with, TF F, including that a false proposition (materially) implies any proposition.
Right. And then the other lines on the truth-table have to conform with, TF F, including that a false proposition (materially) implies any proposition.
What do you mean? I don't understand the sentence about truth tables and TF F.
I agree that a false proposition logically implies any proposition. I also agree that a false proposition materially implies any proposition. This is logically implied by the former.
What do you mean? I don't understand the sentence about truth tables and TF F.
I agree that a false proposition logically implies any proposition. I also agree that a false proposition materially implies any proposition. This is logically implied by the former.
