The author uses the word "immediacy" (line 39) most likely in order to express
Anthony-Resendeson September 2, 2020
Please help! Have not been helped and want to make sure I’m on the right track
So I’ve watched the sufficient and necessary video and through many frustrating night I think I have it down. And please help, because I’ve commented on a couple and haven’t been given insight, granted I was able to find my answer through going through the other students questions, but help with this one so I know if I have the right approach
P: x->z
not z->not x
P: not D->not z
P: ?
_________
C: not D->A
not A -> D
So we have to connect not D->A
A is the new variable, so we look for other sufficient conditions that have not D and we see second premise has not D which is not Z then we see not Z is sufficient for not X there fore not X ->A is the missing premise. Sound right?
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I’m going to walk you through how I approach the missing premise drills. Hopefully, it’s helpful.
Step 1: diagram the contrapositives
P1: X->Z
not Z -> not X
P2: not D -> not Z
Z -> D
P3:
C: not D -> A
not A->D
Step 2: identify the sufficient condition of the conclusion and the conclusion’s contrapositive
not D
not A
Step 3: Do either ‘not D’ or ‘not A’ appear in any of the premises?
‘not D’ appears in P2 as ‘not D -> not Z’
Step 4: connect the current premise to the other given premises
not D -> not Z -> not X
Step 5: make what you know sufficient for what you want.
Since we want not D to be sufficient for not A, we simply add ‘A’ to the end of the chain.
Now we have
not D -> not Z -> not X -> A
so by making the missing premise not X -> A, we complete the chain.
Not X -> A = not A -> X is the missing premise.
Writing out the steps initially helped me learn the correct thought process. As time went on, I no longer needed to follow each step explicitly. It comes naturally, so I don’t spend a lot of time writing each step out.