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Course: LSAT > Unit 1

Lesson 6: Logical Reasoning – Articles
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Logical Reasoning – Articles
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Identify the principle | Learn more

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How do we work with principles in the Logical Reasoning section?

LSAT questions about principles (also called “propositions” or “generalizations”) can take several forms:
  • Identify the principle: The passage is an argument or a situation, and the principle is in the choices.
Which one of the following generalizations is most clearly illustrated by the passage?
Which one of the following principles, if valid, most help to justify the reasoning in the editorial?
The situation as Madden describes it best illustrates which one of the following propositions?
  • Find a situation that conforms to a principle: The choices are all arguments or situation, and the principle is in the passage.
Which one of the following judgments conforms most closely to the principle cited by the columnist?
Which one of the following provides the best illustration of the principle above?
  • Match the principles: There is a principle expressed implicitly in the situation or argument in the passage, and the task is to select the choice that expresses the same principle implicitly. This type of principle question is covered in its own article, Match principles.
Principles occasionally show up in several other question types, including Strengthen and Implications. For instance, the choices for a Strengthen question might take the form of principles that could support a claim.

What exactly is a principle?

You can think of a principle as a general rule, definition, or value that can apply to many different specific scenarios. For example, “Sometimes, unforeseen challenges can make you stronger” is a principle that could govern an infinite number of specific situations, including these examples:
  • Eobard lost his job at the same time that his partner broke off their relationship, leaving him feeling sad. Looking to distract himself, he signed up for a photography class and discovered a real passion for nature photography. This led to a lucrative and fulfilling career for Eobard.
  • When Soon-Ling broke her hand, she was determined to learn how to use her non-dominant (right) hand. Now that her dominant hand is fully healed, Soon-Ling is ambidextrous in most activities.
Laws are a type of principle as well. It wouldn’t make sense to create the following laws:
  • George must wear a seat belt while driving his truck.
  • Tonia must wear a seat belt while driving her sedan.
  • Dianne must wear a seat belt while driving her coupe.
  • George must wear a seat belt while driving Dianne’s coupe.
  • Etc…
Can you see that these laws are too specific to be useful? It’s much simpler—and achieves the same result—if we create an overarching principle instead:
  • One must wear a seat belt while driving any vehicle.
This general principle now governs any of the specific situations that we listed above, as well as all other people and vehicles.

Example: Identify the principle

Hospitals, universities, labor unions, and other institutions may well have public purposes and be quite successful at achieving them even though each of their individual staff members does what he or she does only for selfish reasons.
Which one of the following generalizations is most clearly illustrated by the passage?
(A) What is true of some social organizations is not necessarily true of all such organizations.
(B) An organization can have a property that not all of its members possess.
(C) People often claim altruistic motives for actions that are in fact selfish.
(D) Many social institutions have social consequences unintended by those who founded them.
(E) Often an instrument created for one purpose will be found to serve another purpose just as effectively.

How could we approach this question?

✓ Restate the situation or argument.
For Identify the Principle questions (in which the choices are principles), you’ll be given either an argument (with a conclusion and evidence) or a situation. If it’s an argument, you can identify its evidence and conclusion (the way we do for Assumption, Strengthen/Weaken, Flaw, and others); if it’s a situation, you can rephrase the situation in simple but accurate terms.
In our example, we’re given a specific situation but not an argument. If we read for structure, certain keywords might stand out to us:
Hospitals, universities, labor unions, and other institutions may well have public purposes and be quite successful at achieving them even though each of their individual staff members does what he or she does only for selfish reasons.
Since “even though” signals a contrast, and contrasts are usually rhetorically interesting, we can start there. The arguer is essentially remarking on how:
Even though each individual at an institution can be acting selfishly, the institution as a whole can accomplish good things for the public.
✓ Match your prediction, if you have one.
In this example, we can look in the choices for our prediction. If you didn’t make a prediction, though, you can also evaluate each choice by asking, “Does every part of this choice ‘match’ with something that’s happening in the passage? Or does any part of this choice stray from the passage?”
Try evaluating each of the choices. Even if you’re 100% confident in your answer, practice evaluating each choice and then studying our rationale for that choice below. Build your ability to identify why wrong choices are wrong—instead of focusing only on the answer— and you’ll increase your confidence and speed on Test Day.
Now, let’s work through an example of a Principle question in which the principle is in the passage.

Example: Find a situation that conforms

If an act of civil disobedience—willfully breaking a specific law in order to bring about legal reform—is done out of self-interest alone and not out of a concern for others, it cannot be justified. But one is justified in performing an act of civil disobedience if one's conscience requires one to do so.
Which one of the following judgments most closely conforms to the principles stated above?
(A) Keisha's protest against what she perceived to be a brutal and repressive dictatorship in another country was an act of justified civil disobedience, because in organizing an illegal but peaceful demonstration calling for a return to democratic leadership in that country, she acted purely out of concern for the people of that country.
(B) Janice's protest against a law that forbade labor strikes was motivated solely by a desire to help local mine workers obtain fair wages. But her conscience did not require her to protest this law, so Janice did not perform an act of justified civil disobedience.
(C) In organizing an illegal protest against the practice in her country of having prison inmates work eighteen hours per day, Georgette performed an act of justified civil disobedience: she acted out of concern for her fellow inmates rather than out of concern for herself.
(D) Maria's deliberate violation of a law requiring prepublication government approval of all printed materials was an act of justified civil disobedience: though her interest as an owner of a publishing company would be served by repeal of the law, she violated the law because her conscience required doing so on behalf of all publishers.
(E) In organizing a parade of motorcyclists riding without helmets through the capital city, Louise's act was not one of justified civil disobedience: she was willfully challenging a specific law requiring motorcyclists to wear helmets, but her conscience did not require her to organize the parade.

How might we approach this question?

✓ Diagram or jot down the principle in your own words.
Principles in the Logical Reasoning section are often presented as rules definitions, or laws. Many of them feature conditional logic which can lend itself to diagrams. Many students find easier to evaluate each choice against a diagram than against the entire passage.
If there isn’t any conditional logic, you’ll usually still benefit from jotting down a quick summary of the principle that you’re given.
Our example passage shows some promising conditional logic signals:
If an act of civil disobedience—willfully breaking a specific law in order to bring about legal reform—is done out of self-interest alone and not out of a concern for others, it cannot be justified. But one is justified in performing an act of civil disobedience if one's conscience requires one to do so.
Let’s diagram our principles in shorthand:
  • civ. disobedience = willfully breaking a specific law in order to bring about legal reform
  • if civ. disobed. and self-int. and not concern for others, then not justified
  • if civ. disobed. and/ req’d by conscience, then justified
Note: To strengthen your conditional logic skills and perform better on these question types (as well as on other Logical Reasoning question types and parts of Analytical Reasoning), we recommend these interactive articles:
✓ Evaluate each choice against the principle.
We can’t predict a specific answer for these question types, because any given principle can govern an infinite number of specific scenarios. So we’ll evaluate each choice one at a time, asking, “Does every part of this specific situation conform to the rule/law/definition that the passage presents?” Four of the choices will stray in some way.
Go ahead and evaluate each choice on your own, then compare each of your evaluations to ours:

Summary

Identify the principle:
✓ Restate the situation or argument.
✓ Match your prediction, if you have one.
Find a situation that conforms to a principle:
✓ Diagram or jot down the principle in your own words.
✓ Evaluate each choice against the principle.

Common incorrect choices

Identify the principle:
  • Strays from the situation: These choices are still principles, but they contain parts that don’t match with any part of the passage’s situation or argument.
Find a situation that conforms to a principle:
  • Faulty deductions: These choices commit logical errors, such as believing that If X then Y is equivalent to If not X then not Y or If Y then X.
  • Could be true but doesn’t necessarily conform: These choices are situations or arguments that could be true but the passage’s set of principles doesn’t necessarily support them.

Your turn

Principles
Editorial: One of our local television stations has been criticized for its recent coverage of the personal problems of a local politician's nephew, but the coverage was in fact good journalism. The information was accurate. Furthermore, the newscast had significantly more viewers than it normally does, because many people are curious about the politician's nephew's problems.
Which one of the following principles, if valid, would most help to justify the reasoning in the editorial?
Choose 1 answer:

Principles
Because people are generally better at detecting mistakes in others' work than in their own, a prudent principle is that one should always have one's own work checked by someone else.
Which one of the following provides the best illustration of the principle above?
Choose 1 answer:

Principles
The government-owned gas company has begun selling stoves and other gas appliances to create a larger market for its gas. Merchants who sell such products complain that the competition will hurt their businesses. That may well be; however, the government-owned gas company is within its rights. After all, the owner of a private gas company might well decide to sell such appliances and surely there would be nothing wrong with that.
Which one of the following principles, if valid, most helps to justify the reasoning above?
Choose 1 answer:

A few final thoughts on principles

  • Get ahead of the task. After you recognize that you’ll be working with a principle, it can be helpful to determine whether the principle is in the passage, in the choices, or implied. That will allow you to identify exactly how you’re being asked to work with the principle.
  • Be ready to zoom in and out. Principles can be very broad, very specific, or anywhere in between. If you’re expecting to strengthen an argument with a principle such as, “Daisies can cure depression”, the answer could well be, “Certain flowers can cure depression”, or, “Certain plants can cure some maladies”, or, “Certain objects can provide some types of health benefits”, etc.
  • Principle questions often “act” like other question types. If you improve in Entailment questions, for example, you’ll improve in questions that ask you to identify a situation that conforms to a principle. If you improve in Strengthen questions, you’ll improve in questions that ask you to identify a principle that justifies the passage’s reasoning.

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  • male robot donald style avatar for user Etzion Michaels
    Posted 5 years ago. Direct link to Etzion Michaels's post “How come you tests are so...”
    How come you tests are so hard, but your questions are so easy? Is the test really that hard?
    (6 votes)
    Default Khan Academy avatar avatar for user
  • leaf green style avatar for user dyoffis
    Posted 2 years ago. Direct link to dyoffis's post “so in the second example ...”
    so in the second example choices evaluation, you used the analogy of the spider.

    see spider = scream must have the logical equivalent of

    no scream guarantees no seeing spider. right?

    ofcourse then scream doesnt guarantee seeing spider. but

    in choice E we are given that the act was not justified because it was not required by her conscience.

    this has to be true if you take the passages last line which states

    justified if conscience requires.

    that means conscience requiring you to do something is the only condition you need to justify an act of civil disobedience right?

    and the logical equivalent of that would be that if its not required by your conscience. it is not justified at all.

    have i got this right? if so. then i dont understand why both D and E arent the answer. Because her concience didnt require her to do something that means it was not justified. its not saying that the act was unjustified for sure. only saying that it was not justified aka unprovable to be either justified or unjustified. im confused somebody halp.
    (2 votes)
    Default Khan Academy avatar avatar for user
    • blobby green style avatar for user Simon Rakei
      Posted 9 months ago. Direct link to Simon Rakei's post “I think you are assuming ...”
      I think you are assuming that the choice as it is expressed in E is the actual logical equivalent of the original condition. This isn't necessarily true and there is no way of knowing if that's the case.

      I also considered (E) as potentially correct. But another way to think about the contra positive is to diagram the meaning of the choice as expressed accurately. I agree with the above answer but this could be another way of looking at it.

      According to the stimulus, it is true that the logical equivalent of

      if required by conscience, then justified, is:

      not justified >>> not required by conscience.

      However, that does not mean that you can assume that the answer given in choice (E) and the manner of its expression is *the actual contrapositive* of the original conditional in the stimulus.

      That's the key thing to remember: not to add the assumption that what is given in the choice is the contrapositive, because there are no grounds to do this. Rather, take the "not" statements as they are presented in the choice E as the original conditional for that statement in the answer.

      Thus, the correct diagram of choice E in its original conditional format (and its meaning) is:

      not compelled by conscience >>>> not justified

      This would be the original conditional diagramming of choice E's meaning. That would mean that the actual contrapositive for choice E is

      if justified >>> required by conscience.

      This clearly conflicts with the original rule, which says that

      if required by conscience >>> justified.

      Therefore, the actual contrapositive of choice E would be the converse of the original condition, and not the correct logical contrapositive, because if X >>> Y does not imply Y >>> X.
      (2 votes)
  • blobby green style avatar for user sahand
    Posted 3 years ago. Direct link to sahand's post “How come the answer to th...”
    How come the answer to the first question { editorial and good journalism } is not E?
    (1 vote)
    Default Khan Academy avatar avatar for user
    • leaf green style avatar for user dyoffis
      Posted 2 years ago. Direct link to dyoffis's post “because choice E puts two...”
      because choice E puts two conditions for the journalism to be good. a) that it has to satisfy the publics curiosity and b) that it needs to be accurate.
      but the passage only states one condition for good journalism which is the fact that it needs to be accurate. according to the passage, and dont think outside the passage, according to it, even if the people werent curious it would still have been good journalism because it reported accurate information. it wouldnt have mattered if anyone watched it or not for it to be good journalism.
      (2 votes)