this post was submitted on 13 Jul 2023
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Femboy dilemma (lemmy.world)
submitted 1 year ago by [email protected] to c/[email protected]
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[–] [email protected] 4 points 1 year ago (1 children)

Any inference is valid if its conclusion is known to be true a priori

[–] [email protected] 5 points 1 year ago* (last edited 1 year ago) (2 children)

Not really; an argument is valid if the conclusion is true only when the premises are valid. I believe the argument can be best constructed as follows:

  1. If you think femboys are attractive, you're gay
  2. If you don't think femboys are attractive, you're gay

Therefore, you're gay

Not only is this a valid argument because assuming the premises, the conclusion must be true, it's formally valid because it follows the form

  1. A -> B
  2. ~A -> B

Therefore B

And this argument is valid for all choices of A and B. It doesn't really have anything to do with the conclusion being true.

[–] [email protected] 2 points 1 year ago (1 children)

In other words, the argument is valid but not sound.

[–] [email protected] 1 points 1 year ago

Yeah exactly

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

My statement refers to the construction of ==> from truth tables as a logical gate:

  • Both (False ==> True) and (False ==> False) are True; everything can follow from false premises
  • (True ==> True) is True; A true premise always implies a true conclusion
  • (True ==> False) is False; you cannot infer a falsehood from a truth.

By counting the entries of the table, we see that if Y is True, then (X ==> Y) must always be True no matter what we substitute for X. The joke is that this means we assume foreknowledge of the reader being gay

[–] [email protected] 1 points 1 year ago

Ah I see what you mean; you're right. Though an argument being valid and an implication being true are different things, so I think we misunderstood each other's meaning.