Conditional Chains and A,B,C linkage example

[Dave Killoran]

Hi,

How do you take the contrapositive of a conditional chain, for example, h -> K -> N?

Thank you

The same way you would any conditional statement: reverse and negate! So, looking at your example, we can reverse the order first:


N K H

And then negate the terms:


N K H


Note: the order of reversing and negating doesn't matter; you can do either one first. The key is that both steps have to be taken to create the contrapositive.

This is all over our LSAT Bibles and LSAT courses, so if you haven't encountered those ideas yet, you will!

Thanks!

[andbzav@gmail.com]

Thank you David!

[k100]

Hi,

When it comes to LG, the reasons for linking conditionals are kind of confusing to me. For instance in grouping games, if A B C can be condensed to A C, doesn't this just mean that A, B and C are all in? I guess my question is, what are the benefits of condensing the original chain if the middle variable still needs to be placed in a group (in/out)? Visually, it seems that condensing the chain "erases" the consideration of the middle variable and would confuse me during the questions.

Thanks!

[Adam Tyson]

Not at all, k100! You could very well find yourself looking at a question in which B is not included, and your task will be to see that A cannot be but that C still could be. That is one of their favorite tricks! The inference of "A C" does not erase B from the chain - it's just a way of expressing one of the inferences that is based on that chain. So is "C A."

[Amrita22]

If I had the conditional chain A B C, I cannot conclude A C, correct? Is that because the double arrow is only going back from B?

[Robert Carroll]

Amrita,

That is correct. You can get A B C, so A C, but there's no way to go backwards FROM C, so the second half of that Double Arrow involves a Mistaken Reversal.

Robert Carroll