Confusion about Logical Reasoning Principles

[luckyartiste]

Hi everyone,

I've been studying logical reasoning for the LSAT, and I've come across a concept that's a bit confusing to me. When it comes to conditional statements and logical structure, how do you effectively distinguish between necessary and sufficient conditions in complex arguments? Any tips or insights would be greatly appreciated!

Looking forward to your responses!

Best regards,
luckyartiste

[Jeff Wren]

Hi luckyartiste,

First, conditional reasoning is a major topic on the LSAT and one that generally requires a lot of studying/practice for students, as it isn't something that most people have previously studied.

A thorough discussion of conditional reasoning and its variations/nuances can take several hours. However, I'm happy to provide some general pointers.

First, a great place to start is reading the chapter on conditional reasoning in "The Logical Reasoning Bible." It explains the concepts in detail and also contains useful lists of sufficient and necessary indicator words. If you haven't done so already, you should memorize those two lists and actively look for them whenever you are practicing LR.

These lists are a good place to start and cover most of the conditional reasoning on the LSAT, however, they are not comprehensive, as there are many ways to express conditional reasoning in English.

Ultimately, you want to be able to understand the underlying relationship between the two terms, especially for statements that don't use the standard indicator words. In other words, based on the context of the sentence, which term (i.e. the sufficient) indicates (or guarantees) that the other happens and which term (i.e. the necessary) is required for the other but does not necessarily guarantee that term will happen.

Also be aware that you don't determine the sufficient and necessary based on where it appears in the sentence (i.e. the sufficient can be at the beginning or at the end). You also don't determine the sufficient and necessary based on what "sounds right" or "makes sense" in the real world. The LSAT often uses counter-intuitive conditional statements in order to test whether test takers actually understand the meaning of the sentence.

Finally, be aware that you don't need a sufficient indicator and a necessary indicator. You only need one. Sometimes you determine the necessary condition first and then determine the sufficient (by process of elimination), other times you find the sufficient condition first. It all depends on the wording of the sentence.

In addition, if you have specific conditional statements from the LSAT that you don't understand, feel free to ask about them on the forum.