LSAT Principle Questions, Part I

Update 2015: Practice makes perfect. You can find a list of principle questions + explanations for those questions here:


People often find LSAT principle questions confusing.

At first glance, this is strange. Principle questions are similar to regular question types. There are strengthen questions, parallel reasoning questions, etc. So why are LSAT principle questions hard?

It’s because principle questions are more abstract. The principles aren’t necessarily tied to a specific situation, and that’s hard to think about.

This is a two part blog post. In the second half, you’ll learn about LSAT principle questions types, and you’ll find a list of principle questions.

The first half covers something more basic, but even more important: what a principle is.

What Is A Principle?

In real life, we get away with using words imprecisely. This is fine. But on the LSAT (and in law), you need to be very precise with words. So you should know exactly what a “principle” is.

A good dictionary is surprisingly helpful for many LSAT terms, including this one. A principle is:

  1. A fundamental truth or proposition that serves as the foundation for a system of belief or behavior or for a chain of reasoning.
  2. A rule or belief governing one’s personal behavior.

If you accept a principle is true, it should change your thoughts or actions. And LSAT principle questions ask you to accept principles as true! So the right principle will change what you think of a situation.

You are not trying to figure out if the principles are true in real life. That is the wrong question to ask.

Instead, ask yourself “If this principle were true, would it change the situation?”

Narrow vs. Broad Principles

It’s important to know exactly when a principle applies to a situation. Consider these two principles. They sound similar, but one is much broader:

  • “New parents should eat a healthy diet.”
  • “Anyone who works should eat a healthy diet.”

The second principle is much broader.

If you accept that a principle is true, it will affect how you act or how you think about a situation.

Suppose you accepted the above principles, and that you work. You’re deciding whether to eat a chocolate bar. The principle does the job for you. Don’t eat it.

“I work, therefore I should eat a healthy diet. Therefore, I should not this chocolate bar.”

Take-away: Principles are often if-then (conditional) statements. You can use them to make formal logical deductions. In certain situations, a principle will force you to change your mind.

Bonus Question: What about someone who doesn’t work, and isn’t a parent. Should they eat a chocolate bar?

We don’t know. The principles don’t tell us anything about people who don’t work and aren’t parents. We have no idea what they should or should not do.

An Example

Let’s look at an example.

A robber comes to your house, and steals your computer. You lose all your pictures and music. Later, the robber turns himself in to police. He apologizes, says the robbery was a moment of weakness, and repents.

The robber is prepared to accept whatever punishment the law thinks appropriate. This is the robber’s third crime, and he will go to jail for life if found guilty.

Unfortunately, the computer was broken in the robbery, and you can’t get any data back.

The police come to you, and ask if you want to press charges. What do you say?

You might have already decided what to do. Or maybe you’re stuck and can’t decide between vengeance and pity. How do you decide, and what could force you to change your mind if you’ve already decided?

Applying Principles To The Example

There are certain principles that, if accepted, would force you to decide one way or the other. Suppose you believed that:

“Anyone who commits a crime must be punished, for the good of society”.

This principle tells you what to do. The robber committed a crime. Therefore, he must be punished. If you accept the principle, you have to believe this is true, even if you think the robber did a good thing by turning himself in.

Likewise, if you believe the following principle, the situation is clear:

“Anyone who repents of a crime deserves mercy and should not be punished.”

You can’t press charges if you truly believe this.

These are the kind of principles to look for. They express a firm belief that can change how you view a situation.

Some Principles Don’t Affect Anything

The wrong answers on an LSAT principle question typically describe a principle that has no effect, or a situation that isn’t affected by a principle. It’s very important to be able to identify when a  principle has no effect.

So let’s look at a few principles that won’t help us decide anything. See if you can figure out why they’re useless:

  • “All convicted criminals must be sent to jail.”
  • “You should not have mercy for a criminal who does not repent.”
  • “You should only punish a criminal if they cause irreparable damage.”
  • “You should only have mercy for a criminal if they repent.”

Did you figure out what was wrong with them? The first two apply to the wrong groups. The robber is not yet a convicted criminal. And since the robber did repent, the second principle doesn’t apply.

This is very important. A principle that doesn’t apply to the case at hand has no effect.

The final two principles are trickier. They tell us necessary conditions for punishing a criminal or having mercy. The first one says you can’t punish a criminal who didn’t cause permanent damage.

But our criminal did cause permanent damage. So this principle is useless. It tells us we could punish him, but not that we should or that we must.

The same analysis applies to the principle about mercy. If you find this confusing, it means you need to do more work on what sufficient and necessary conditions mean. I’ve written more about this in my Basic Logic section.

That’s it for discussion of what a principle is. Check out Part II for more on LSAT principle question types, and a list of principle questions from tests 29-38.

Then, take a look at Part III to find explanations for a few sample principle questions, and to see a list of all the principle questions from LSATs 29-38.

LSAT Principle Questions: Strengthen

LSAT principle questions can seem confusing, but they’re really just other question types in disguise. For example, often we’re asked to use a principle to strengthen or weaken an argument.

These questions are just like normal strengthen or weaken questions, with one twist: the answers are phrased as abstract principles.

What Question To Ask Yourself About Each Answer

The right answer should force you to change your mind about the argument’s conclusion.

Let’s say I make the following argument:

“Even though there are useful ways we could spend tax money, we should cut taxes to boost economic growth.”

You may not agree with that argument, but you can see there’s at least a potential case to be made. If you do agree with it, you can surely see that it is not perfect.

Here’s a wrong answer:

“Economic growth is a good thing.”

It sounds a little tempting. The conclusion said that we should aim for growth, and this says growth is good.

But…would this principle force anyone to change their mind. Some people might think that we could achieve even more good by spending the tax money.

Further, it’s a very obvious principle. Practically everybody agrees that economic growth it good. That makes it a warranted assumption, something that we could assume anyone because no one would disagree with it.

Take Each Statement At It’s Weakest

Most people look at the answers to an LSAT question, and try to see whether it’s possible they’ll be useful. That’s the wrong approach. You should ask yourself whether it’s possible that the answer wouldn’t be useful.

The wrong answer above said that economic growth is good. But how good? We don’t know. Maybe economic growth is the best thing in the world. Or maybe it’s good, but not very good. Maybe it ranks a little higher than “steamed peas” on the scale of goodness.

So, properly speaking, the question to ask yourself is:

“If everyone agreed that economic growth was slightly good, would that convince them that we definitely should cut taxes to boost economic growth?”

“No”, is the answer to that question. There’s still room for disagreement.

What a Right Answer Looks Like

Take this statement:

“If some action will boost economic growth, then the government should take that action.”

Now ask yourself:

“If someone accepted that statement is true, would they have to agree that we should cut taxes to support economic growth?”

Yes, they would. The correct answer on a “principle: strengthen/weaken” question will force you to change your mind, if you accept that the principle is true.

Some students think that this kind of answer is “too strong”. I have no idea what that means. A strong answer choice does more than it needs to, but that’s fine, as long as the answer does help the argument. If you’re supporting an argument, you can never be “too strong”.

Update 2015: I’ve now written thousands of free explanations at LSAT Hacks, including explanations for principle strengthen questions:

Asking The Right Questions on the LSAT

Almost everyone has trouble correctly eliminating LSAT answer choice. Most people ask the wrong questions.

What do I mean by “asking a question” about the answer choices? I’ll use an example from logic games. Imagine a “Must be True question”.

During a lesson, I often hear my students say out loud “could this be true?”. It’s a terrible question to ask.

The right question to ask is: “Could this be false“? If the answer could be false, then it’s wrong. It it can’t be false, then it must be true. Asking if something could be true adds no information.

I’ll explain with a real world example. Which one of the following must be true about the sky:

A. It’s cloudy
B. It’s not cloudy
C. It’s dark.
D. It’s bright.
E. It’s blue (during the day)

What happens if you ask “could this be true?”. Each answer can be true! The sky can be cloudy, or not cloudy, or bright and sunny, or dark at night. The question failed to eliminate any answer.

If you ask “could this be false?”, then the answer to A-D is “yes”, but the answer to E is “no”.  E is correct, the sky is blue.

You should ask a question that will eliminate any wrong answer. The right question will be different, depending on the type of question.

Update: If you liked this article, I now have a free five part email course with more info about getting a good LSAT score:

As for asking the right question, you can review the free explanations I’ve written here:

The questions show you my thought process, and what criteria to use to choose/eliminate answers.


LSAT 64 Explanations Available

Update: Now I sell explanations for many LSATs here.

Did you write the October 2011 LSAT? Are you thinking of writing again in December?

I’m sure you looked over your copy of the test, and tried to figure out where you went wrong. But you may not always understand why you were wrong. Sometimes you aren’t even sure why you were right!

There’s a better way. There are clear reasons why every answer choice is either right or wrong.If you invest a bit of time into understanding why the right answers are right, you’ll do much better on all future tests.

Luckily for you, I’ve written explanations for the entire exam. LSAT Blog published LSAT 64 about a week ago, and I got my hands on a copy. I worked through it as fast as I can, because I know there are lots of people trying to figure out how to do better in December.

Learn How To Increase Your LSAT Score

For $3.99, you’ll get complete explanations for every section. Use them with your copy of test 64 and you’ll learn why every answer is right or wrong. You’ll also get diagrams for every logic game.

There’s not much time left before the December LSAT, but these explanations will give you an edge. Study where you went wrong on LSAT 64, and you’ll learn how to improve your score a month from now.

Interested?  They’re only $3.99. Here’s what to do:

How to Get the Explanations (Test 64 sold separately)

1. Click the buy now button below.

2. You’ll go to the payment page. Once it loads, you can pay using paypal.

3. Once you pay, you’ll get taken to the download page. You’ll instantly get a pdf copy of the explanations for test 64. They’re yours to keep and to print, and they come with a 100% satisfaction guarantee.

Want to score better in December? Just click the button below.


Note: You’ll need your own copy of test 64 for these to be useful.

The LSAT is A Reading Test

I tutor people for the LSAT.  Often, my advice on a specific question boils down to this (I don’t say it this way)

“Did you read all of the words and understand them?”


“Well, see that word?  It changes the meaning completely”

Student:  Oh!  There’s a “not” there.  …now I get it.

Most people studying for the LSAT will find themselves in this situation.  I’m in this situation sometimes, when I don’t understand a question (it happens, now and then).  It’s not your fault:  the people who write the LSAT are very clever.  They write questions in such a way that makes it easy to miss words or misunderstand otherwise simple concepts.

If you’re stuck between two answers, there’s clearly something you don’t understand.  Wrong answers are never “sort of right” (trust me on that one).

Most likely, you missed a word, or misunderstood a word.  So when you’re stuck on the LSAT, tell yourself this:

“I’m smart, but clearly I’ve missed something.  One of these is right, and one of these is wrong.  I had better look over everything again, and forget the assumptions I have at the moment.  Clearly they’re wrong or incomplete.  But if I look at this with fresh eyes, I may be able to see what I missed.”

Don’t actually say that, it will take too long.  But cultivate that attitude.  It’s the attitude I have when I’m stuck, and it’s why I don’t stay stuck.  There are reasons I do well on the LSAT, and that’s one of them.

How to Make it Through the LSAT

Imagine two people studying for the LSAT.  Here’s what they’re thinking while they’re doing the questions.

Person 1:  *I hate the LSAT! Why is this so hard?*

Person 2: *Hmm, I wonder how this works. I don’t understand. But maybe if I tried this…*

Who do you think will do better?

Yes, the LSAT is hard.  But if they made it easy, then everyone would get a high score and you still couldn’t get into Harvard. Worrying about how hard the LSAT is will not get you a better LSAT score.

Curiosity, however, will help you to improve. Approach the problems as fun puzzles to be solved. This may sound like the hardest thing in the world, but it works.

People who approach the LSAT as a problem to be solved don’t get tired when they write the test. You know that feeling you get on the fourth section, when you feel you can’t go any further?

Well, I don’t. And I never did. Even when I first started, even when I didn’t understand logic games, I looked at them as a challenge to be solved. That attitude took me a long way.

It’s not just me.  My students who view the test as a challenge report that they don’t feel tired, either. How often do you get tired doing something fun but challenging?

If you’re not already there, change won’t come overnight. But work on seeing the LSAT as a fun challenge that will make you a better thinker once you master it. I promise you’ll do better as a result.

Update: If you liked this article, I now have a free five part email course with more info about getting a good LSAT score:

Explanations for LSAT preptest 29

I’ve written explanations for LSAT preptests 29-38.  They’re available for sale on LSAT Blog.  For each question I’ve:

  • Identified the Question Type
  • Identified the Conclusion and the Reasoning (If it’s an argument)
  • Written an analysis of the question’s logic
  • Written explanations for why the right answer is correct and why all of the wrong answers are wrong.


I know it’s hard to decide if something if useful without seeing it first.  So I’ve posted a sample.  The explanations for the first half of preptest 29 are available for free.

If you think the entire set will be useful, buy them on LSAT Blog.

Why The LSAT Is Hard (And What To Do About It)

The LSAT is not a test of logic

I used to think it was. The LSAT definitely involves logic. But I now believe that the LSAT is mainly a test of reading comprehension, attention to detail and lateral thinking.  (Logical reasoning, anyway.  Logic games take a bit more logic)

I’ll explain with an example.

A few days ago I was talking to a chiropractor.  He complained about what was wrong with his profession. He told me most chiropractors focussed on expensive techniques that didn’t heal patients. Meanwhile, simple exercise could fix most problems. He asked me why I thought chiropractors did that.

I said: So that they’ll have less repeat patients.

He said: Yes, exactly…no wait: don’t you mean they’ll have more repeat patients?

I agreed. Of course that’s what I meant. I said less when I meant more. Fortunately, I didn’t fail the conversation. Because this sort of thing happens all the time. People say the exact opposite of what they mean. Or they completely mix up key terms.

It’s doesn’t matter. In everyday conversation, people tend to understand you. They’ll stop and clarify if there’s confusion.

It works the same in the papers you read for undergrad. You might have misunderstood a key concept the first time you read it. But by the fifth time you read the concept, you probably figured out what was going on. You can’t get through four years of university while completely misunderstanding what you were studying.

You Only Get One Chance On The LSAT

It doesn’t work like that on the LSAT. You don’t get points for “having the right idea and picking the wrong word.” And it does you no good if you “pick what would have been the right answer if you had only spotted a slight nuance in the question.”

LSAT logical reasoning questions give you one short paragraph to understand. You don’t get to ask anyone to clear up any confusion. If you make a slight mistake, no one will point it out. And you won’t come across a later question that tells you that you misunderstood the first question.

Instead, you have to get things right. I helped a student solve a question yesterday where the wrong answer said “criminal” and the right answer said “potential criminal.” One little word completely changed the meaning of the answer choice. No one will watch over your shoulder to make sure you pick up on that that. You have to learn to spot such things yourself.

Doesn’t Logic Have Anything To Do With The LSAT?

Yes, it does.  But the logic is hard mainly because its used in unfamiliar contexts.  If I say:  You need gas to drive your car, most people will correctly understand that I mean “If you don’t have gas, you can’t drive” and “If you can drive, you have gas.”

But If I say that positronic computers require advanced wireless circuitboards…many people will scratch their heads.  I’ve said exactly the same thing, logically.  A needs B.  But because people don’t think they know what a positronic computer they find the second sentence much more difficult.  And it is difficult to understand when the LSAT uses complex wording.

But the logic behind “A needs B” isn’t hard.  It’s the context that makes it hard.

So LSAT logic is hard because they try to make it difficult to understand and spot the logical relationships. They’ll use two similar terms that mean different things. They’ll use two different terms that mean the same thing. They hide the logic in plain sight.

How To Get Better At The LSAT

If you don’t understand the question then you’ll never be able to answer it. So why do so many students rush on to the answer choices without really understanding what they read?

On most questions it’s possible to figure out what the right answer will be before you even look at the answer choices. You just have to read carefully. Here’s what to do.

1. Slow Down

Yes, slow down. You’ll be able to understand the questions better. And if you understand, then you’ll eventually go faster. But this time, you’ll get the questions right.

2. Pay Attention To Little Things

The LSAT loves to fool you with little difference. Low vs. lower. Percentage vs. Total Number. Employee vs. Potential Employee. Etc. Watch out for small differences that indicate a completely different idea.

3. Make Sure You Understand

Don’t skip over something because it seems complicated. The LSAT sometimes uses complex wording but it always includes enough simple words that you can understand…if you try.

3. Don’t Be A Robot

I said it’s important to look for little differences.  But don’t get hung up on them.  It’s normal for people to switch words sometimes, and the LSAT does the same without always having a reason.  If the stimulus says “big” and and answer choice says “large”, it doesn’t mean you have to focus on that and assume it’s the key to the question.

4.  Understand The Question, Then Think About It

The LSAT increasingly demands lateral thinking.  Older tests emphasized strict logic.  Newer tests emphasize intuitive leaps.  Question 6 from the first section of preptest 29 mentions that “smoking, drinking and exercise” can affect the level of cholesterol in the blood.  The right answer mentions that “lifestyle” factors can affect the risk of heart disease.  I’ve had students puzzle over this question.  They wrote off the right answer automatically without thinking about it, because the stimulus didn’t say “lifestyle factors.”

They were looking for logic when the LSAT was asking them to use common sense:  smoking, drinking and exercise are part of our lifestyle and we can change them.