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One of my weaker areas seems to be conditional logic, so I ordered a used copy of Copi/Cohen's intro to logic textbook from Amazon for like 6$. It has great reviews on Amazon, and read that this book has helped some people with their prep. Did anyone find using a logic textbook useful for prep?

I took an advanced symbolic logic class during my time prepping for the LSAT. We read Lemmon's Beginning Logic and some intermediate level propositional logic book, which I cannot seem to recall the name of. Nonetheless, working with challenging material in logic allowed me to better grasp the logical reasoning sections in general and also helped with certain parts of logic games (specifically, transcribing tricky rules appropriately, etc.). These types of books definitely go over and beyond what is required for the LSAT; yet Manhattan and Powerscore's formal logic sections will sufficiently prepare you for anything you are likely to encounter on the test. However, if you have the time and patience/motivation, I would recommend going through a well-known textbook in logic.

PS: Nice avatar. Never can have too many fans of the ole time and space conquering moralist from Konigsberg.

Honestly I think a formal logic textbook is going to give you an unnecessary amount of information and have diminishing returns. I took a very basic logic class a few semesters ago which gave me a really good grasp on conditional logic, but it's a really easy concept that I think you can master without looking at it in an academic setting (or with academic text). I guarantee there are websites that will be able to give you some great conditional logic exercises in a form that's very basic and distilled like the kind you see on the LSAT, where it's just variations of "if, then" with some "and" and "or" thrown in there. No need to buy a textbook of which you'll only use like four pages.

LSAT logic is pretty simple and something everyone should already intuitively understand, so you don't need to learn anything, just practice it.

I used a logic textbook. Any cheap book will do. Maybe try to find something with a lot of problems. The benefit would be getting it down quickly and naturally so practice is more important than depth. I didn't miss a single LR, in large part because of sorta mentally diagramming questions quickly.

Thanks for the responses guys. I figured I'd get a logic textbook anyway and checkout a few pages and see what I can pull out of it. I mean, it was a measly 6$ anyway, which was more on the expensive side as far as used logic textbooks go, haha.

The two logic chapters of my logical reasoning textbook are online at the publisher's site (Routledge - do a search for 'Tittle Routledge Welcome' to get to the right page); they're a lot more basic than the Copi text, but, as people are saying, should be sufficient for the LSAT.

Sorry to hijack your thread, but what about in terms of purely prep books? I'm trying to decide between Manhattan and PowerScore. I have the PowerScore version for logic games and I really like that book. However Manhattan is 15 bucks cheaper (so I could another booklet of 10 prep tests with that money), and I've also heard good things about that. What do ya'll think?

RamTitan wrote:Sorry to hijack your thread, but what about in terms of purely prep books? I'm trying to decide between Manhattan and PowerScore. I have the PowerScore version for logic games and I really like that book. However Manhattan is 15 bucks cheaper (so I could another booklet of 10 prep tests with that money), and I've also heard good things about that. What do ya'll think?

I did both Manhattan and Powersocre. If you're going to pick one I'd do Powerscore.

Cambridge has all of the old LSATs for sale and I believe it's cheaper than buying those booklets of 10.

OP, I had some exposure to formal/symbolic logic, but I don't think that spending a lot of time on a textbook is really worth much of your study time. It's probably a good intellectual exercise--and will certainly help you think more clearly--but for the LSAT, you really don't have to go into the kind of depth that you find in a typical formal logic textbook. Maybe it's a good study break, but I would focus instead on knowing how to diagram every kind of conditional rule out there and develop a system that you apply to every formal logic and games diagramming question on the LSAT that you don't deviate from.

For example, "if and only if" always introduces a bi-conditional or double-arrow relationship; every time I see that phrase I think "double-arrow" and write: A<-->B. Not A <--> not B. It takes no thought after learning the rule and drilling it in your system via repetition, those two things will always follow each other.

Another one that throws people off: A or B, but not both. Automatic, instant reaction in my head (and on paper): (A or B) AND (not A or not B).

Getting that kind of instant, no-thought-required fluency is what gets you really fast and brutally effective--and it gives you more time for harder questions.

One thing I did was make up a lot of hypothetical diagramming examples based on exercises and examples from LSAT stimuli that I found were tricky on the left hand side of a notebook paper, draw a line down the middle, and write the correct diagramming on the right. You'll forget your examples after a few days and be able to drill yourself up and down the page periodically to get a little faster and more fluid. The goal with diagramming is to get a really simple and instantly usable systems; so I wouldn't spend a lot of time learning the finer points of memorizing syllogisms, learning the finer points of the propositional calculus, or becoming a truth table sensei. Although, as a fun (cough) study break, it probably won't hurt to do those things, and maybe it will even help you in some indirect/making you smarter ways--who knows?

Good luck OP, and feel free to PM me if you run into diagramming troubles along your LSAT journey!

BlueprintJason wrote:OP, I had some exposure to formal/symbolic logic, but I don't think that spending a lot of time on a textbook is really worth much of your study time. It's probably a good intellectual exercise--and will certainly help you think more clearly--but for the LSAT, you really don't have to go into the kind of depth that you find in a typical formal logic textbook. Maybe it's a good study break, but I would focus instead on knowing how to diagram every kind of conditional rule out there and develop a system that you apply to every formal logic and games diagramming question on the LSAT that you don't deviate from.

For example, "if and only if" always introduces a bi-conditional or double-arrow relationship; every time I see that phrase I think "double-arrow" and write: A<-->B. Not A <--> not B. It takes no thought after learning the rule and drilling it in your system via repetition, those two things will always follow each other.

Another one that throws people off: A or B, but not both. Automatic, instant reaction in my head (and on paper): (A or B) AND (not A or not B).

Getting that kind of instant, no-thought-required fluency is what gets you really fast and brutally effective--and it gives you more time for harder questions.

One thing I did was make up a lot of hypothetical diagramming examples based on exercises and examples from LSAT stimuli that I found were tricky on the left hand side of a notebook paper, draw a line down the middle, and write the correct diagramming on the right. You'll forget your examples after a few days and be able to drill yourself up and down the page periodically to get a little faster and more fluid. The goal with diagramming is to get a really simple and instantly usable systems; so I wouldn't spend a lot of time learning the finer points of memorizing syllogisms, learning the finer points of the propositional calculus, or becoming a truth table sensei. Although, as a fun (cough) study break, it probably won't hurt to do those things, and maybe it will even help you in some indirect/making you smarter ways--who knows?

Good luck OP, and feel free to PM me if you run into diagramming troubles along your LSAT journey!

This is an extremely helpful reply. I really appreciate you taking the time to write this out, and will definitely take this into account when I study more conditional logic. Your suggestion for drawing hypothetical diagrams next to LSAT stimuli sounds like a really good idea, so I'll be doing it the next time I study LR. Hopefully, if it works well I can also spread this tip to others as well. Thanks!

Alex93 wrote:

BlueprintJason wrote:OP, I had some exposure to formal/symbolic logic, but I don't think that spending a lot of time on a textbook is really worth much of your study time. It's probably a good intellectual exercise--and will certainly help you think more clearly--but for the LSAT, you really don't have to go into the kind of depth that you find in a typical formal logic textbook. Maybe it's a good study break, but I would focus instead on knowing how to diagram every kind of conditional rule out there and develop a system that you apply to every formal logic and games diagramming question on the LSAT that you don't deviate from.

For example, "if and only if" always introduces a bi-conditional or double-arrow relationship; every time I see that phrase I think "double-arrow" and write: A<-->B. Not A <--> not B. It takes no thought after learning the rule and drilling it in your system via repetition, those two things will always follow each other.

Another one that throws people off: A or B, but not both. Automatic, instant reaction in my head (and on paper): (A or B) AND (not A or not B).

Getting that kind of instant, no-thought-required fluency is what gets you really fast and brutally effective--and it gives you more time for harder questions.

One thing I did was make up a lot of hypothetical diagramming examples based on exercises and examples from LSAT stimuli that I found were tricky on the left hand side of a notebook paper, draw a line down the middle, and write the correct diagramming on the right. You'll forget your examples after a few days and be able to drill yourself up and down the page periodically to get a little faster and more fluid. The goal with diagramming is to get a really simple and instantly usable systems; so I wouldn't spend a lot of time learning the finer points of memorizing syllogisms, learning the finer points of the propositional calculus, or becoming a truth table sensei. Although, as a fun (cough) study break, it probably won't hurt to do those things, and maybe it will even help you in some indirect/making you smarter ways--who knows?

Good luck OP, and feel free to PM me if you run into diagramming troubles along your LSAT journey!

This is an extremely helpful reply. I really appreciate you taking the time to write this out, and will definitely take this into account when I study more conditional logic. Your suggestion for drawing hypothetical diagrams next to LSAT stimuli sounds like a really good idea, so I'll be doing it the next time I study LR. Hopefully, if it works well I can also spread this tip to others as well. Thanks!

You are very welcome! I love making drills like this. Let me know if anything else is giving you fits and I'll try to come up with something similar if I can. Definitely pay it forward if you have a study buddy or someone having similar diagramming issues!

Good luck!

PS- I dig you tar!