LR Bible, Chapter 6, pgs. 161-162, #5 and #8

[vjunkins]

Thanks, ill go ahead and search for those drills! I decided to open up my LR Bible and review chapter 6 "conditional reasoning" again. I do have multiple books from PowerScore such as all the bibles, all the workbooks, and the full online class books as well. I am having some difficulty with "unless". In the LR Bible, chapter 6 pgs. 161-162 are diagramming drills. For question # 5 and #8 are the unless where you use the unless equation, however I got them completely wrong. This is what I did:

#5: M=meeting P= 6 people ~=not (slash)

~m ----> p
~p------> m

But I see in the answers it should be like this:
m--------> p
~p-------->~m

Don't you have to negate the sufficient since unless modifies the necessary?


#8: C=computer OS=operating system ~=not (slash)

~C------->OS
~OS------>C

Reading further into it, what I think I might have been doing wrong for the unless equation is that since there is already a "not" in both questions the opposite of "not" would be no slash which is why the answers for both were having no slashes and then the contrapositive is showing both with slashes?

Now if there was no not in the question then there would be a slash in the answer?
For example: A computer can operate without an operating system.
~C------->OS
~OS------>C

I hope this made sense while you were reading it.

Thanks!
Victoria

[Dave Killoran]

Hi Victoria,

For #5 and #8, you are correct: if a negative such as "not" is present, then when you apply the Unless Equation it negates that "not" and it becomes "clear." If there was no negative present in the original statement, then a slash would appear on the sufficient once it was converted.

So, you ultimately answered your own question—good job!