Conditional Reasoning and Formal Logic

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Conditional Reasoning and Formal Logic

Postby fosterp » Tue Jul 06, 2010 12:23 am

I am going through the LRB and in these two sections with conditional reasoning and formal logic I am started to get overwhelmed with information. Its mainly translating actual conditional statements into symbolic form and then the application of formal logic rules to a chain of sentences. Do you guys think its necessary to study conditional rules and the formal logic sections. The rules make sense to me, its just sort of applying them when the stimulus gets overly wordy and complicated that gets me. Mainly the easy-medium questions I figure out in my head with pretty good accuracy but the ones that are harder just sort of make my head hurt, and trying to apply the rules of logic to figure out the answer "mechanically" sort of just results in me spending a lot more time than I should on the question. Of course the explanations use the mechanical explanation to get the right answer, so is memorizing these sections really the only way to consistently get the hard ones right? Or can deducing in my head sort of come quickly and naturally with enough practice tests?

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Re: Conditional Reasoning and Formal Logic

Postby WestOfTheRest » Tue Jul 06, 2010 12:29 am

You can do it in your head but you first have to be able to do it with diagrams. There are conditional questions that you absolutely will not get right if you do not use formal logic.

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Re: Conditional Reasoning and Formal Logic

Postby koolfrog11 » Tue Jul 06, 2010 12:57 am

One tip I can give about this is be sure you are reading the stimulus VERY carefully. Most LR questions are not formal conditional reasoning. You will have one or two tops per section. The test makers can write questions that sound like CR but are actually strengthen questions etc. So don't fret too bad. Beyond that just don't freak when you see one. That's what I did in the beginning of studying. These types were prolly my worst question in practice but I didn't miss one on the real thing. Just look at it, make sure it's CR, take a breath, and take it sentence by sentence. Don't try to draw conclusions until after you've written out all the relationships. as far as the rules, the main ones you need to look at are logic chains and how to get a contrapositive. Mapping the question isn't bad. If Sally eats peanuts, she gets sick goes to SEP--->GS. It's not too bad as long as you keep you abbreviations straight all the way through the problem

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Re: Conditional Reasoning and Formal Logic

Postby am060459 » Tue Jul 06, 2010 2:17 am

with conditional reasoning you have to practice a lot. make sure your foundation is strong and the rest will fall into place (this is true with most, if not all, of the lsat).

good luck

Audio Technica Guy
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Re: Conditional Reasoning and Formal Logic

Postby Audio Technica Guy » Tue Jul 06, 2010 8:01 am

The mistake people make is thinking that conditional reasoning doesn't show up a whole lot and you only need to kinda sorta understand it. It's everywhere on the LSAT. If you've ever seen an answer choice that says something along the lines of "takes something that is necessary for an event as sufficient to cause the event" then yep, that's CR. I've found that if you're bad/mediocre at CR, really, really getting it is worth 10 points. This doesn't mean that you have to write them out every time, but if you're struggling with writing them out, its a sign that you don't understand them very well. And they're ALL OVER the arguments and games sections. IN-Out games for instance, most people who struggle with those struggle with them because they're not as good with the contrapositive as they should be. The contrapositive should be 100% automatic. You don't even think about it, it just pops out.

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Re: Conditional Reasoning and Formal Logic

Postby tidepool » Tue Jul 06, 2010 8:34 pm

Stripping down verbose language to formal logic is a skill that takes practice to develop. It sounds like you are just starting this process. So don't get discouraged. If all goes right in your studies, you will be able to take any lengthy sentence or sentences about dinosaurs, or volcanos, or municipal townships (or whatever) and write down a simple diagram that expresses just the essential logical elements. Good luck!

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Re: Conditional Reasoning and Formal Logic

Postby smc44 » Tue Jul 06, 2010 9:01 pm

I would forget about formal logic for now. I would keep studying the chapter on conditional reasoning until you know it cold. You should be able to recognize conditional reasoning whenever it is used in a stimulus. Some time later, after you really understand conditional reasoning, go back to the formal logic chapter.

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