Invalid argument form bathroom sign?

J. Tharp

I don't know what this means but just for kicks:


Invalid, right?

quinnxzhang

Well, it's not an argument, so validity doesn't come into play. It's just an imperative sentence, like "open the door".

Ganbatte

to make it two flawed arguments:

if what is to be flushed is toilet paper and what nature provides, then flush.
Thus, since what is to be flushed is not toilet paper nor what nature provides, I will not flush.

A -> B
Not A
_______
Thus, not B.
(assumes not A->not B; B->A)

Formally the error is mistaken negation.
Can be called mistakes necessary for sufficient or sufficient for necessary.
Overlooks the possibility that there are other sufficient reasons for flushing, so you really don't know if you will flush or not, since logically, you cannot infer from A->B, Not A-> ??.

OR

if what is to be flushed is toilet paper and what nature provides, then flush.
Thus, since I will flush, it must be because what is to be flushed is is toilet paper and what nature provides,

A->B
B
______
Thus, A
(assumes B->A)

Formally the error is mistaken reversal.
Can be called mistakes sufficient for necessary or necessary for sufficient.
Overlooks the possibility that there are other sufficient reasons for flushing or other necessary conditions to flush. Again, you can't infer knowing A->B from B -> ??.

Someone check my example and make sure I got the distinction between mistakes necessary for sufficient or sufficient for necessary right?

Nicole Hopkins

@"J. Tharp" said:
I don't know what this means but just for kicks:

Yes!

J. Tharp

@quinnxzhang I meant that the illustration represented an invalid argument form
and @Gumbatte Yes! I love the effort you put into this!