LR Guide Ch. 12 Diagramming Matches.

[CaitlinC257]

Hello,
I am having a lot of difficulty understanding the answer key's stated logical ordering in two drill statements on page 524-525 of your LR book (Ch. 12: Drill it: Diagramming Matches). The answer key does not have any explanation for its answers.

4.) When Alicia goes to a party, she brings booze, and wherever there's booze, there's cocktails. Alicia is going to the party, so there will be cocktails.
How is this an illegal reversal? A---->B B------>C A--->C makes sense to me. But the answer choice states A----->B B---->C, A/C, basically stating that if Alicia goes,we can't say there will be cocktails. I really don't understand this because it appears exactly like a logical chain with 3 components. If she goes to a party, she definitely brings booze. If there are booze, there are cocktails, so how does her arrival not necessitate cocktails?!

6). What is the difference between 5, All animals breathe, so if something doesn't breathe, it isn't an animal (which is written in the answer key as a contrapositive statement) and 6, All animals breathe, but since my pet rock does not, my pet rock is not an animal. All you did was replace "something" with a "pet rock." How can that be a different statement? Is there something in the semantics that I am missing?

Please help. This is really confusing me, and I want to make sure I am proficient in my understanding of logical structures for the exam.
Thank you.
Caitlin

[CaitlinC257]

Actually, after looking over the answers a second time and the directions with an explanation, I think I do understand. The line represents a result rather than a condition. So the line indicates that the condition has been applied in absolute terms? I had assumed from earlier in the book (and I hadn't really been paying attention to this notation previously) that the line represented an illegal reversal. Is it correct, then that the line indicates that the condition has been applied in absolute terms?
Thank you.

[ohthatpatrick]

I might be confused about which part you're asking about, but I see how there's not enough explanation there.

When they're writing conditional logic statements, they're using the "--" sign as a negative that means "not".

~A = - A = "not A"

When you see a long line before the last idea, they're separating the evidence from the conclusion.
It's meant to look like you're "adding up" the ideas above the line in order to derive the conclusion below the line.

Let me know if that leaves you still feeling confused about how any of them look / match up.