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Course: LSAT > Unit 1
Lesson 6: Logical Reasoning – Articles- Getting started with Logical Reasoning
- Introduction to arguments
- Catalog of question types
- Types of conclusions
- Types of evidence
- Types of flaws
- Identify the conclusion | Quick guide
- Identify the conclusion | Learn more
- Identify the conclusion | Examples
- Identify an entailment | Quick guide
- Identify an entailment | Learn more
- Strongly supported inferences | Quick guide
- Strongly supported inferences | Learn more
- Disputes | Quick guide
- Disputes | Learn more
- Identify the technique | Quick guide
- Identify the technique | Learn more
- Identify the role | Quick guide
- Identify the role | learn more
- Identify the principle | Quick guide
- Identify the principle | Learn more
- Match structure | Quick guide
- Match structure | Learn more
- Match principles | Quick guide
- Match principles | Learn more
- Identify a flaw | Quick guide
- Identify a flaw | Learn more
- Match a flaw | Quick guide
- Match a flaw | Learn more
- Necessary assumptions | Quick guide
- Necessary assumptions | Learn more
- Sufficient assumptions | Quick guide
- Sufficient assumptions | Learn more
- Strengthen and weaken | Quick guide
- Strengthen and weaken | Learn more
- Helpful to know | Quick guide
- Helpful to know | learn more
- Explain or resolve | Quick guide
- Explain or resolve | Learn more
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Identify an entailment | Learn more
Identify an entailment that follows logically from given statements
You’re given a set of statements. Your task? Determine what else must be true, based on those statements.
How do I recognize entailment questions?
Look for questions that ask you what must be true, or for what logically follows; sometimes the question asks you instead for what the conclusion would have to be if the statements in the stimulus are true:
If the statements above are true, which one of the following must also be true?
Which one of the following logically follows from the statements above?
Which one of the following can be properly inferred from the statements above?
Let’s work through an example together!
Example
If there are any inspired musical performances in the concert, the audience will be treated to a good show. But there will not be a good show unless there are sophisticated listeners in the audience, and to be a sophisticated listener one must understand one's musical roots.
If all of the statements above are true, which one of the following must also be true?
(A) If there are no sophisticated listeners in the audience, then there will be no inspired musical performances in the concert.
(B) No people who understand their musical roots will be in the audience if the audience will not be treated to a good show.
(C) If there will be people in the audience who understand their musical roots, then at least one musical performance in the concert will be inspired.
(D) The audience will be treated to a good show unless there are people in the audience who do not understand their musical roots.
(E) If there are sophisticated listeners in the audience, then there will be inspired musical performances in the concert.
How might we approach this question?
✓ Break the passage down into individual claims.
A good way to start is to list (usually mentally, or sometimes with some quick notes if the claims are hard to keep track of) all of the claims that the arguer makes. Think of these as building blocks that we can then reassemble to support a conclusion.
1) If there are any inspired musical performances in the concert, the audience will be treated to a good show, but
2) There will not be a good show unless there are sophisticated listeners in the audience, and
3) To be a sophisticated listener one must understand one's musical roots.
✓ Look for ways that the passage’s statements interact and relate.
It’s likely that the most obvious way this will happen is when two statements involve the same terms. Those two statements might link up to support a conclusion, or make a larger relationship, for example:
Some dogs are cuddly.
All cuddly things are cute.
Since the two statements contain the term cuddly, we can use cuddly as the connector term, combining the statements to deduce that
Some dogs are cute.
In our example, we see a couple repeating terms:
good show
sophisticated listener
Through diagramming, we can investigate any potentially useful connections between good show statements and sophisticated listener statements.
✓ Identify conditional statements and consider diagramming them.
Support often includes one or more conditional statements. These tend to be strong claims, and they are very useful for generating conclusions. It’s a good idea to notice conditionals wherever you come across them. If there are multiple conditions, and especially if they include common terms, it may be a good idea to diagram them.
1) If there are any inspired musical performances in the concert, the audience will be treated to a good show.
- inspired mus. perf. in concert
2) There will not be a good show unless there are sophisticated listeners in the audience
- good show
3) To be a sophisticated listener one must understand one's musical roots
- soph. listen.
As you may be able to see, we can connect these statements! Notice how good show is the result of one statement and the trigger for another statement. The same is true of sophisticated listeners. That means that we can create one long chain of logic:
- inspired mus. perf. in concert
and the logically equivalent statement is
- not understand roots
The answer will reflect some relationship that we derived from the statements here.
Top tip: Follow the arrow! The logic can only progress in the direction of the arrow and not against it; in other words, you'll want to proceed from left to right, but never from right to left.
If you'd like more help with conditional logic, check out our favorite article on the subject: If X, then Y | Sufficiency and necessity.
✓ To test a choice, ask, “If everything in the stimulus is true, does this claim have to be true? Or could it be false?"
You can often make a strong prediction in Entailment questions the way we did above. But in the cases where you can't or don't make a prediction, you can still test the choices one at a time.
Remember, we’re looking to fill in a missing deduction. What’s the definition of a deduction? It’s something that follows necessarily from evidence. In other words, an entailment (or deduction) cannot be false if the information in the stimulus is true.
You can test a choice, therefore, either by asking if it can be proven using the statements in the passage, or by considering whether the choice can ever be false (even if only once).
- If you can prove the choice using the statements in the passage, then you have the answer.
- If the answer to the question “Can this choice ever be false?” is yes, even if only in a few exceptional cases, then you should look for the answer elsewhere.
Summary
Keep the following tips in mind when you confront an Entailment question:
✓ Break the passage down into individual claims.
✓ Look for ways that the passage’s statements interact and relate.
✓ Identify conditional statements and consider diagramming them.
✓ To test a choice, ask, “If everything in the stimulus is true, does this claim have to be true? Or could it be false?"
✓ Look for ways that the passage’s statements interact and relate.
✓ Identify conditional statements and consider diagramming them.
✓ To test a choice, ask, “If everything in the stimulus is true, does this claim have to be true? Or could it be false?"
Common Incorrect Choices
- Could be false — Often, incorrect choices are claims that receive some support from the information but that nevertheless could be false even though all of the information is correct.
- Too much of a reach — Choices are often incorrect because they take things beyond what the evidence supports. They might be too strong or too specific, for example. If the passage states that something is unlikely to happen, a wrong choice might reflect that that something won't happen.
- Conditional mistakes — When the question involves conditional logic, there are often a couple of choices that look good but involve conditional fallacies. For example, they might confuse a necessary condition with a sufficient condition.
Your turn!
Takeaways
- Finding entailments is similar to taking disparate pieces of evidence to determine what must be true. There's no room for speculation in entailment questions.
- When you’re breaking down the stimulus, pay extra attention to conditional statements and logically strong premises (such as “all” and “must” statements). An answer can be strong, but never stronger than the passage that supports it.
- Try to make your own deductions before you consider the choices, then anticipate possible answers. However, keep in mind that there may be numerous deductions possible, so you won't always be able to clearly anticipate the answer.
- When looking over the choices, test each one by asking, “Does this have to be true? Or could it actually be false?”
- Be wary of (but don't automatically eliminate) choices with very strong or specific language; they might be overreaching, depending on what the passage states.
- Remember that the answer has to be guaranteed by the information in the stimulus, not just supported by it. That's the main difference between these question types and Strongly Supported questions.
Want to join the conversation?
Hello, I wanted to ask about the sequencing of the first entailment question. It appears to me that "inspired musical performance" and "sophisticated listeners" are written as they were separate.
I sequence the question as follows:
"good show-> inspired musical performance
good show -> sophisticated listeners -> musical roots".
The way I understand the question, I believe one needs both seperate elements of elements of "inspired musical performance" and "sophisticated listeners".
Am I wrong in believing this? If I am right, then answer A is wrong.(26 votes)- I figured it out. If 'inspired musical performances' is A, 'a good show' is B, and 'sophisticated listeners' is C, then it would read as A=B and B=C. Therefore, A=C. However, the problem with this is that the same logic would work with answer E, making this just a poorly constructed question in general.(2 votes)
- "A modern reader and a nineteenth-century reader interpret one of Shakespeare's sonnets in the same way."
Technically speaking, which is what entailments are supposed to do anyway, there is nothing in the passage that forbids two readers, by some means, even if highly unlikely, from coming to the same meaning despite having radically different belief systems.(7 votes)
From the author:Hi Wade! The passage tells us the following things:
* Meaning ... is always the unique result of an interaction between a reader's system of beliefs and the poem; and,
* Any two readers from different cultures or eras have radically different systems of beliefs.
You're absolutely right to think about entailments in terms of "technically speaking" - it's important to treat the LSAT's language with precision. And when we consider these two items together, they lead to an entailment that a modern reader (let's call it from Era X) and a nineteenth-century reader (we'll call that Era Y) cannot find the same meaning in a poem. They have "radically different" systems of beliefs, and since the system of belief is one ingredient, and the poem (which never changes) is the other, the information we're given means that any two people from any two different eras will find different meaning.(12 votes)
- I am a bit confused about the example question about the musical performance.
I understand that in order for an inspired performance to result in a good show the audience has to have members who know their roots and are therefore sophisticated listeners.
But the passage never says that in order for there to be an inspired performance there needs to be sophisticated listeners, but rather that in order for that inspired performance to produce a good show there needs to be sophisticated listeners. So isn't it completely possible that an inspired performance indeed took place but that there was no resulting good show because there were no sophisticated listeners in the audience, which would make option A incorrect?(5 votes) - Choice (A) should be worded "If...~...then THERE WILL NOT BE A GOOD SHOW" ? The meaning of "inspired" is "of extraordinary quality, as if arising from some external creative impulse". "Inspired" talks about the quality of the performance, not inspiration due to the musical ear of the audience. The audience cannot transfer "inspiration" to the performance by being musically educated. In other words, the performance could be inspired without having an educated audience in music.(2 votes)
I know this is too late but the answer to this question is to not go on the literal meanings of words. You have to apply no prior knowledge, just the one given in the question.(5 votes)
- There will not be a good show unless there are sophisticated listeners in the audience.
Why isn't this diagrammed as follows:
Not a good show --> No sophisticated listeners
This conditional diagram would state, correctly, that if a show is not good, there are no sophisticated listeners in the audience.
But then the contrapositive isn't accurate- that if there are sophisticated listeners, then the show was good. But I don't understand where the disconnect is coming from because the original conditional looks sound.(2 votes)- From the author:Hi Wade! This is a really common question. "There will not be a good show unless there are sophisticated listeners in the audience" means that it's necessary for sophisticated listeners to be in the audience in order to have a good show, right? Just like "I can't go in the sun unless I'm wearing sunscreen" means that sunscreen is necessary for me to go into the sun. But we can't translate that as "not in the sun -> no sunscreen". Because I could be inside in the dark and still wearing sunscreen!
In the same way, if there isn't a good show, that doesn't mean that there are no sophisticated listeners. Sophisticated listeners are necessary to having a good show. But having sophisticated listeners doesn't guarantee a good show, and a bad show doesn't guarantee an absence of sophisticated listeners.
I hope this helps! Check out the article on contrapositives for more help :)(5 votes)
- Can someone please diagram the conditional statements for question one? I'm not understanding what happened to the "most" conditional statement or how these were combined to form this valid inference.(4 votes)
- I have the same query as Denise Gonzalez had. Can anyone please help to resolve this query?
From the question stem, it appears that there are 2 conditions that must be satisfied to make a show good. Condition-1 there must be inspired performance. Condition-2 Audience must be sophisticated and again this factor is dependent on whether audience know its roots.
Why 2 conditions are logically necessary?
Let me give you an example.
If mathematics teacher is good, student will score high in mathematics. But student will not score high unless student is at least an average performer in mathematics, and to be an average performer, student must have scored 70% in previous year mathematics class.
If we apply the analogy of option A in my example, it illogically implies that mathematics teacher isn't good because student is below the average. That sounds weird right? Similarly, if the audience is dumb(i.e. the audience is not sophisticated), we can't say that the performance is not inspiring. Performance can still be inspiring as it is the audience which can not understand the greatness of the performance.
Therefore, I have a doubt regarding correctness of option A.(4 votes) - Can you direct me to how I can practice more of these problems? I cannot find it on the practice section. Thanks(2 votes)
- A little late but...in case anyone else is looking for more practice, these types can be found under the deductions and inferences practice sets.(4 votes)
- Under the evaluation for choice D it says:
This choice is the opposite of what we’re looking for and therefore it must be false. It indicates that it’s necessary for there to be people in the audience who do not understand their musical roots in order for there to be a good show, but we were told that it’s necessary for there to be people in the audience who do understand their musical roots in order for there to be a good show.
...but neither of the conditionals from the examples of D indicate a requirement for there to be listeners who don't understand their musical roots in order for their to be a good show.(2 votes)- From the author:Hi Wade - looks like (D)'s explanation was missing the word "not" in "in order for there to not be a good show" - good eye, and thank you so much!(2 votes)
- Hello. For practice question 1: Interior Decorator, when I click "check" it's not showing me what the correct answer is. It's only showing me that what I chose, (option C) is incorrect.
C states: Most coffeehouses that are well designed, feature artwork.
If all coffeehouses and restaurants are public places, and most well designed public places feature artwork, then I don't understand why C is incorrect, especially after evaluating all other options.(1 vote)
