LSAT LR questions often make arguments. They run the gamut from persuasive and logically valid to misguided and flawed. As an LSAT taker, you need to become an expert critic. You need to be combative, incisive, and quick on your feet.
One of the essential features of argumentation, both on the LSAT and in life, is arguing from the general to the specific– from principles to actual instances. In today’s lesson, we are going to take a very close look at the topic of speaking broadly, i.e., using principles. While LSAT instructors and students often refer to certain LR questions as “principle questions,” it can be a little counterproductive to think of principles as a specific question type. Rather reasoning that involves principles shows up in a lot of other question types. To master principles, you have to be adept at working with them in a lot of different contexts. Here we are going to get you started in the right direction.
Definition of a Principle
First, let’s get our definitions in hand. A principle is a rule of general applicability (meaning it could apply to more than one entity or event) that makes a judgment. For example, I could say, “all LSAT students should devote a substantial amount of time to the LSAT.” That’s something I believe, by the way. Now, from this statement, a general principle that applies to any and all people taking the LSAT, you know I believe that if you are taking the LSAT, you should devote a lot of time to it.
A principle makes a judgment about the way the world should be.
A principle makes a judgment about the way the world should be. Compare this with something that simply presents facts, such as the statement “studying for the LSAT takes a substantial amount of time.” Now, this statement may or may not be true. However, if we just view this statement by itself, it’s presented as a fact. All it’s takes is one little word, however, and we can convert it back into a principle of general applicability: “studying for the SHOULD take a substantial amount of time.” Whenever there is an element of judgment in there, you are working with a principle.
Scope of Principles
Principles apply to the group being discussed. The above principle applies to all LSAT takers. I could narrow it like so: “LSAT students in the Mastermind Study Group should devote a substantial amount of time to the LSAT.” Now we are talking about a much smaller group: just people in the Mastermind Study Group. It may appear to you to be common sense that if people in the Mastermind group should study a lot, then everyone should. The principle, however, doesn’t tell us that. It just tells us about people in the group.
LSAT questions repeatedly test your ability to understand the scope of rules
If you should take just one thing away from this lesson, it’s this: you need to maintain constant awareness of the scope of principles. They only apply to the group under discussion. Try to grant them broader applicability (get beyond the scope), and you’ll be headed for a certain disaster. LSAT questions repeatedly test your ability to understand the scope of rules, which is what principles are. Take the following simple example, with a premise and conclusion:
Premise: LSAT students in the Mastermind Study Group should devote a substantial amount of time to the LSAT.
Conclusion: Justin, who is taking the LSAT, should devote a substantial amount of time to it.
Is this conclusion warranted from this premise? No, not without making some assumptions (unstated premises) that connect the premise to the conclusion. We don’t know if Justin is in the group or not. He might be on the outside, in which case the rule (the principle) doesn’t necessarily apply to him. To properly conclude this conclusion for this premise, you’d need to know that Justin is indeed in the group.
If you are trying to apply a principle to something– an occurrence or an entity of some kind– make certain that this something is covered within the rule’s scope. Think of it as a cliff edge. The moment you are out of scope, you have fallen off the cliff. The rule no longer applies.
Conditionality of Principles
Another way to understand this concept of scope is to see principles for what they are: conditional statements. Because they are conditional statements, literally everything you’ve learned about conditional statements applies to them. I wish someone would have just told me this up front when I started learning principle questions because it makes them way less scary. You’ve likely already learned how to work with them.
Take any principle, and you’ll see that it can be defined in terms of a sufficient and a necessary condition. Take our example principle:
LSAT students in the Mastermind Study Group should devote a substantial amount of time to the LSAT.
Written as a more familiar “If-then” statement, that looks this:
If you are an LSAT student in the Mastermind Study Group, then you should devote a substantial amount of time to the LSAT.
Here is kind of a long-form diagram of that:
LSAT student in the Mastermind Study Group —–> should devote a substantial amount of time to the LSAT
Make sure the part making the judgment doesn’t get taken out when translating into a conditional statement. In this case, that’s the word should. Remove that, and you get a very different rule: “If you are an LSAT student in the Mastermind Study Group, then you devote a substantial amount of time to the LSAT.” That’s no longer a principle.
Returning to the question of scope, another way to say that something is out of scope is to say that it’s simply not a trigger for this rule. Look at the rule again with too additional premises:
Principle: If you are an LSAT student in the Mastermind Study Group, then you should devote a substantial amount of time to the LSAT.
Additional Premise 1: Justin is taking the LSAT
Additional Premise 2: Josh, who is also taking the LSAT, is in the Mastermind Study Group.
What can you properly infer from this? Which of the two premises can act as a trigger for the rule? Answer: Premise 2. Because we know Josh is in the group, the conditional rule applies to him. You can then make the following inference through modus ponens:
Possible inference: Josh should devote a substantial amount of time to the LSAT.
Bam. It’s just like working with any other conditional statement. Does that mean you have to diagram principles? That will depend on the situation, but it helps to be aware that they operate the same as any other conditional statement. You can make contrapositives (“If it’s not the case that you should devote a substantial amount of time to the LSAT, then you are not in the Mastermind Study Group”). If you have additional premises, you may be able to make inferences via modus ponens, modus tollens, or syllogism. That’s all you can do. Try anything funny, and you’ll go wrong, just as with conditional statements.
So, take away two things from this lesson:
- Stay within scope. If something isn’t in the group explicitly discussed by the principle doesn’t apply.
- Principles are just conditional rules. The laws of conditional logic apply.
One last wrinkle just so you don’t go mad when you encounter something like this: sometimes principles are pretty well hidden. Remember that sentence I told you was not a principle? Here it is: “Studying for the LSAT takes a substantial amount of time.” What if that now appeared in the following context:
“Evan studied for a couple of days and did poorly on his LSAT. That is not surprising. Studying for the LSAT takes a long time.”
Here, it looks like the speaker is just sort of throwing a fact on the end. However, I’d argue that they are making a value judgment there. Clearly, it’s possible not to study for a long time. Evan did it. However, the speaker thinks that is no good. It’s implied that he is stating a principle: that studying properly does take a long time. As an “if-then” statement, that would look something like this:
If you want to study properly for the LSAT, then that studying takes a long time.
So conceivably, principles can be hidden and arise out of context. While the LSAT thankfully doesn’t get this fancy often, be aware that principles, like any other conditional statement, don’t necessarily have that neon sign we’ve talked about pointing to them, that “if-then” language.
Okay, that’s it for today. We’ll take a look at some more specific question types where you encounter principles in upcoming lessons.
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LSAT Logical Reasoning Lessons
