The author uses the word "immediacy" (line 39) most likely in order to express
Greeron August 7, 2020
Missing Premise Flashcards with 3 Premises
Could you provide an example walk-through of a question with three premises? I don't have trouble with questions containing only two premises and a conclusion but am struggling to understand the questions with three premises (like what are found in the missing premise flashcards).
Replies
Create a free account to read and
take part in forum discussions.
Thanks for the question! So I just pulled a random missing premise flashcard to go through. We’re given the following information:
P: Y —> C P: ? ?P: A —> ~B C: B —> C
So now the question becomes: how do we get to B —> C? Well, in the premises, we want to have a B in the sufficient premise. That way, we can go
B —> Stuff
And we want to have a C in the necessary condition in the premises. That way, we can have
Stuff —> C
And then ideally we’d link that together to get
B —> Stuff —> C
Which would get us the conclusion we want, B —> C. Now take a look at the third premise. We have ~B in the necessary condition. Well, if we take the contrapositive of this, we’ll get B in the sufficient condition, which is what we want! So let’s take the contrapositive of premise 3, or
B —> ~A
And note that the first premise gives us C in the necessary condition, we have
B—> ~A Y —> C
Now we want something that bridges these two to get us to B —> C. We can do that by connecting the ~A and Y! So from
B — > ~A and Y —> C (1)
we can just say
B —> ~A —> Y —> C (2)
Which would get us B —> C. And how can we get (2) from (1)? Well, if we assume
~A —> Y is true, and that’s the missing premise that we need. Note that the contrapositive also works, ~Y —> A.
Hope this helps! Feel free to ask any other questions that you might have.
