Must be true questions are the questions I miss most ... and I discovered that you can answer at least some (I have barely tested this idea, could be all of em) using basic symbolic logic / propositional logic truth trees. The only downfall to this method is that it is slow. Has anyone used this?
I'm considering getting good enough at truth trees to be able to use them fruitfully for inference questions quickly, since the method seems pretty fool proof and I wouldn't mind spending an extra minute or so on a question to guarantee I get it right. If anyone has thoughts on this / additional ideas / has done this, let me know.
Has anyone ever thought of using truth trees for MBT Qs?

 Posts: 381
 Joined: Mon Sep 06, 2010 5:16 pm
 SumStalwart
 Posts: 201
 Joined: Wed Aug 01, 2012 2:37 am
Re: Has anyone ever thought of using truth trees for MBT Qs?
Yes, many of them you can solve with symbolic logic. However, it takes too damn long. I use them on some of the more complicated ones. I wouldn't recommend using it too often, because you will likely run out of time. I can usually get them done much faster without engaging in any writing.
That's just my two cents.
That's just my two cents.
 NoodleyOne
 Posts: 2358
 Joined: Fri May 25, 2012 7:32 pm
Re: Has anyone ever thought of using truth trees for MBT Qs?
Truth trees would take forever. MBT don't tend to be incredibly difficult. If you have extra time at the end and want to use it to doublecheck, go ahead, but there are better ways to spend your time in most circumstances.

 Posts: 381
 Joined: Mon Sep 06, 2010 5:16 pm
Re: Has anyone ever thought of using truth trees for MBT Qs?
So you don't think it's possible to do them quickly? The SL used for the LSAT stuff is pretty easy. You could blaze through it
 SumStalwart
 Posts: 201
 Joined: Wed Aug 01, 2012 2:37 am
Re: Has anyone ever thought of using truth trees for MBT Qs?
It's not that I don't think that you could get "fast" at them, it's that you can be faster without them. In addition, there are better things to do with your time. I agree with Noodley, if you want to, you can use them to double check your answers at the end.
 CyanIdes Of March
 Posts: 745
 Joined: Thu Aug 16, 2012 1:57 pm
Re: Has anyone ever thought of using truth trees for MBT Qs?
It seems like a waste of time to practice them to the level you'd need to be to assign all the variables accurately and then use the tree to deduce the answer considering there's usually only 1 MBT question per section. Also, there are some common patterns they use and strategies posted around the forum that knowledge of and a littlbe bit a drilling will give you quicker results.

 Posts: 74
 Joined: Wed Jun 20, 2012 11:20 pm
Re: Has anyone ever thought of using truth trees for MBT Qs?
This is what you will have to draw if you use Truth Trees:
If you have 2 propositions, then you will have 4 possibilities, only one of which is True True, and so valid
If you have 3 propositions, then you will have 8 possibilities, only one of which is True True True, and so valid.
If you have 4 propositions, then you will have 16 possibilities, only one of which is True True True True, and so valid.
I guess you could learn to do this really fast, but if you have 4 propositions, you are probably going to run out of space on that page of your test booklet.
It is almost always better to do the LR's using the method that the LSAC wants to test whether you are proficient in or not.
The MBT Q's are meant to test your ability to do simple propositional and categorical deductive logic, and you can always find the correct AC using deductive logic. So, it is better for you to learn to do propositional and categorical logic. Not only will you need far less time for writing and take up less space on your booklet, you will also learn a method that can be applied to many questions other than LR MBT questions. Properly Inferred LR questions can often be solved using propositional or categorical logic, and other LR questions as well. Plus, Logic Games often can be quickly solved using p. or c. logic. In particular, you can solve the 2 or 3 Group Logic Games *very* quickly, if you use logical symbolism that is keyed to the LSAT and you know how the relatively simple logic works.
And most important of all, you will use this kind of logic in Law School and in your law practice as well. You would be surprised at how many practicing lawyers undermine their own competence by not mastering the logic that is much easier to learn than most of what you will learn in Law School.
So, really, it will saving lots of time and effort in the whole of your legal career if you learn simple p. and c. logic. And it is really not very hard at all. You just have to learn it from the right book or tutor or both.
If you have 2 propositions, then you will have 4 possibilities, only one of which is True True, and so valid
If you have 3 propositions, then you will have 8 possibilities, only one of which is True True True, and so valid.
If you have 4 propositions, then you will have 16 possibilities, only one of which is True True True True, and so valid.
I guess you could learn to do this really fast, but if you have 4 propositions, you are probably going to run out of space on that page of your test booklet.
It is almost always better to do the LR's using the method that the LSAC wants to test whether you are proficient in or not.
The MBT Q's are meant to test your ability to do simple propositional and categorical deductive logic, and you can always find the correct AC using deductive logic. So, it is better for you to learn to do propositional and categorical logic. Not only will you need far less time for writing and take up less space on your booklet, you will also learn a method that can be applied to many questions other than LR MBT questions. Properly Inferred LR questions can often be solved using propositional or categorical logic, and other LR questions as well. Plus, Logic Games often can be quickly solved using p. or c. logic. In particular, you can solve the 2 or 3 Group Logic Games *very* quickly, if you use logical symbolism that is keyed to the LSAT and you know how the relatively simple logic works.
And most important of all, you will use this kind of logic in Law School and in your law practice as well. You would be surprised at how many practicing lawyers undermine their own competence by not mastering the logic that is much easier to learn than most of what you will learn in Law School.
So, really, it will saving lots of time and effort in the whole of your legal career if you learn simple p. and c. logic. And it is really not very hard at all. You just have to learn it from the right book or tutor or both.
Return to “LSAT Prep and Discussion Forum”
Who is online
Users browsing this forum: Exabot [Bot] and 5 guests