Suggestions for text on formal logic. Forum

[lillawyer2]

Does anyone know any books that can help me understand formal logic, as it pertains to the LSAT?

I want something to supplement my study for the LSAT.

Despite the techniques taught in Blueprint and Manhattan, I don't have a well rounded understanding that allows me to really "get it". I am able to follow what is taught, but mess up on some questions (especially the harder ones) because I don't truly understand formal logic.

[Pneumonia]

If you're messing up, it isn't because you don't understand formal logic. If you must get a book, I'd suggest Walton's "Informal Logic." Blueprint's methods are great, and if you're having trouble applying them to the questions I can almost guarantee that formal logic is not what you should be worrying about. Your question is kind of like saying "I having trouble with arithmetic, can someone recommend an algebra book to help me out?"

[lillawyer2]

If you're messing up, it isn't because you don't understand formal logic. If you must get a book, I'd suggest Walton's "Informal Logic." Blueprint's methods are great, and if you're having trouble applying them to the questions I can almost guarantee that formal logic is not what you should be worrying about. Your question is kind of like saying "I having trouble with arithmetic, can someone recommend an algebra book to help me out?"

So, I understand your point, but i disagree.

However, i'll bite. Since my understanding of formal logic is not the problem. Pray tell what do you think is the problem? It's not very nice to refute and not offer an alternative. You kind of left me hanging in that respect.

Anyway thank you for the recomendation. Even though you think it will not help.

[Blueprint Mithun]

Does anyone know any books that can help me understand formal logic, as it pertains to the LSAT?

I want something to supplement my study for the LSAT.

Despite the techniques taught in Blueprint and Manhattan, I don't have a well rounded understanding that allows me to really "get it". I am able to follow what is taught, but mess up on some questions (especially the harder ones) because I don't truly understand formal logic.

Can you be a little more specific about what's giving you trouble? Is it contrapositives? Sufficient vs. necessary conditions? Chaining together conditional statements? When to apply conditional logic to an LR question? All vs. Most vs. Some statements?

Formal logic on the LSAT doesn't really extend beyond the topics that I just mentioned. It uses very basic conditional logic - what makes some of those questions hard is the way the arguments are written, which is often in a purposefully obfuscating manner. The formal logical content of these questions doesn't go past the most elementary concepts. A text on logic would go much further than what you need to learn for this test.

Maybe looking at some basic truth tables would help. Truth tables are a basic and intuitive way of visualizing conditional logic. Check out this link: http://kias.dyndns.org/comath/21.html

Note that "or" on the LSAT is equivalent to the logical OR, not XOR, which we're used to in common speech. Also, ignore the whole bit about the "implication" operator, which doesn't appear on the LSAT.

[Panoptikon]

Barwise and Etchemendy. Language, Proof, and Logic.

[lillawyer2]

Does anyone know any books that can help me understand formal logic, as it pertains to the LSAT?

I want something to supplement my study for the LSAT.

Despite the techniques taught in Blueprint and Manhattan, I don't have a well rounded understanding that allows me to really "get it". I am able to follow what is taught, but mess up on some questions (especially the harder ones) because I don't truly understand formal logic.

Can you be a little more specific about what's giving you trouble? Is it contrapositives? Sufficient vs. necessary conditions? Chaining together conditional statements? When to apply conditional logic to an LR question? All vs. Most vs. Some statements?

Formal logic on the LSAT doesn't really extend beyond the topics that I just mentioned. It uses very basic conditional logic - what makes some of those questions hard is the way the arguments are written, which is often in a purposefully obfuscating manner. The formal logical content of these questions doesn't go past the most elementary concepts. A text on logic would go much further than what you need to learn for this test.

Maybe looking at some basic truth tables would help. Truth tables are a basic and intuitive way of visualizing conditional logic. Check out this link: http://kias.dyndns.org/comath/21.html

Note that "or" on the LSAT is equivalent to the logical OR, not XOR, which we're used to in common speech. Also, ignore the whole bit about the "implication" operator, which doesn't appear on the LSAT.

I only understand conditional logic when the passage isn't convoluted. ---> When the passages are more dense with run on sentences or just in general very long, I find it hard to do formal logic. I also find it hard to interpret "some, most" statements with the arrows and then using that to conclude w.e. about the argument. It gets frustrating that I just want to skip the whole process.

I know that when (if) it finally clicks I will do so much better on the LSAT.

[Archer@Law]

I am using formal and informal logic textbooks along with the LSAT Trainer for my prep.

For formal, I am using Introduction to Logic by Harry Gensler. It touches on traditional formal logic, but also deals with English arguments in conventional and idiomatic form (similar to LR questions). It can be done with Gensler's software called logicola which contains a multitude of different logic exercises.

I personally like using the text alongside the software, as it gives instant confirmation on whether or not you are wrong.

As others have mentioned, however, it is up for debate whether or not it will translate to increased LSAT scores. Only using the text for a couple of weeks now, so I am hesitant to provide even my own anecdotal recommendation.

[usaorbust]

Barwise and Etchemendy. Language, Proof, and Logic.

I would not recommend the LPL book. The book is basically First Order Logic, and the rules and such that they teach you are pretty useless for the LSAT.

I also would not recommend any "Formal Logic" books, its not that useful for supplement material. If anything I would use informal logic, which will cover a lot of the topic on the LSAT as posters mentioned earlier. Formal logic is more Proof logic instead of common language logic.

[AntsInMyEyesJohnson]

I am using formal and informal logic textbooks along with the LSAT Trainer for my prep.

For formal, I am using Introduction to Logic by Harry Gensler. It touches on traditional formal logic, but also deals with English arguments in conventional and idiomatic form (similar to LR questions). It can be done with Gensler's software called logicola which contains a multitude of different logic exercises.

I personally like using the text alongside the software, as it gives instant confirmation on whether or not you are wrong.

As others have mentioned, however, it is up for debate whether or not it will translate to increased LSAT scores. Only using the text for a couple of weeks now, so I am hesitant to provide even my own anecdotal recommendation.

Both Gensler's book and the software would likely help to at least a small degree, since many of the syllogisms aren't totally dissimilar from what you see in the LR sections. Plus, Gensler makes everything pretty straightforward. A classic in the realm of intro to logic is Peter Kreeft's Socratic Logic. While the benefits might be minimal, it certainly wouldn't hurt you on the LSAT to be comfortable with formal logic, especially if you get up to Gensler's stuff on modality, since at that point you've got to be pretty comfortable with basic propositional logic (which is all that the LR is).

FWIW, my training in logic came after I had already taken the LSAT and I regretted immediately not having studied all of that before I took the test. But who knows if it actually would have had an impact on my score.

[Archer@Law]

I am using formal and informal logic textbooks along with the LSAT Trainer for my prep.

For formal, I am using Introduction to Logic by Harry Gensler. It touches on traditional formal logic, but also deals with English arguments in conventional and idiomatic form (similar to LR questions). It can be done with Gensler's software called logicola which contains a multitude of different logic exercises.

I personally like using the text alongside the software, as it gives instant confirmation on whether or not you are wrong.

As others have mentioned, however, it is up for debate whether or not it will translate to increased LSAT scores. Only using the text for a couple of weeks now, so I am hesitant to provide even my own anecdotal recommendation.

Both Gensler's book and the software would likely help to at least a small degree, since many of the syllogisms aren't totally dissimilar from what you see in the LR sections. Plus, Gensler makes everything pretty straightforward. A classic in the realm of intro to logic is Peter Kreeft's Socratic Logic. While the benefits might be minimal, it certainly wouldn't hurt you on the LSAT to be comfortable with formal logic, especially if you get up to Gensler's stuff on modality, since at that point you've got to be pretty comfortable with basic propositional logic (which is all that the LR is).

FWIW, my training in logic came after I had already taken the LSAT and I regretted immediately not having studied all of that before I took the test. But who knows if it actually would have had an impact on my score.

Added to the book list.

To the OP, keep in mind that I work on Gensler's stuff in addition to my work in the Trainer. It does not substitute for my main LSAT work. Most of the time, I end up doing Gensler's stuff at work when I'm not busy. It doesn't seem to require as much focus as actual LSAT work does. But it does give me more exposure to logical concepts than I otherwise would.

[Barack O'Drama]

Does anyone know any books that can help me understand formal logic, as it pertains to the LSAT?

I want something to supplement my study for the LSAT.

Despite the techniques taught in Blueprint and Manhattan, I don't have a well rounded understanding that allows me to really "get it". I am able to follow what is taught, but mess up on some questions (especially the harder ones) because I don't truly understand formal logic.

Can you be a little more specific about what's giving you trouble? Is it contrapositives? Sufficient vs. necessary conditions? Chaining together conditional statements? When to apply conditional logic to an LR question? All vs. Most vs. Some statements?

Formal logic on the LSAT doesn't really extend beyond the topics that I just mentioned. It uses very basic conditional logic - what makes some of those questions hard is the way the arguments are written, which is often in a purposefully obfuscating manner. The formal logical content of these questions doesn't go past the most elementary concepts. A text on logic would go much further than what you need to learn for this test.

Maybe looking at some basic truth tables would help. Truth tables are a basic and intuitive way of visualizing conditional logic. Check out this link: http://kias.dyndns.org/comath/21.html

Note that "or" on the LSAT is equivalent to the logical OR, not XOR, which we're used to in common speech. Also, ignore the whole bit about the "implication" operator, which doesn't appear on the LSAT.

I think this is TCR. I took several classes geared towards logic in UG assuming it would help me with the LSAT. It did, but maybe only 5% of it. The very rudimentary and basic logic stuff.

[Pneumonia]

OP – it's pretty clear from your second post that your issue is translating English sentences into formal logic terms, not formal logic itself. That is what I suspected (it's the same issue everyone has, because that is what the LSAT tests), and that is why a formal logic book won't help you. You need to practice reducing convoluted sentences into their component parts, not understanding what conditions also obtain when A --> B. In other words, stick with the LSAT prep. Any divergences into formal logic are going to be a waste of time.

[lillawyer2]

OP – it's pretty clear from your second post that your issue is translating English sentences into formal logic terms, not formal logic itself. That is what I suspected (it's the same issue everyone has, because that is what the LSAT tests), and that is why a formal logic book won't help you. You need to practice reducing convoluted sentences into their component parts, not understanding what conditions also obtain when A --> B. In other words, stick with the LSAT prep. Any divergences into formal logic are going to be a waste of time.

Thank you for coming back.

Is there a strategy for this? I cant see how ppl can do this so quickly for the exam