Lesson 7.2: Parallel Reasoning Questions

Introduction

In this lesson, students, we will explore the concept of Parallel Reasoning Questions within the Logical Reasoning section of the LSAT. Parallel reasoning questions are designed to assess your ability to identify the underlying structure of an argument and match it with another argument that has a similar logical form. This skill is crucial for success on the LSAT, as it allows you to efficiently navigate complex questions while focusing on the relationships between premises and conclusions.

Learning Objectives

By the end of this lesson, you should be able to:

Match a valid argument's structure to one answer choice.
Use conclusion type and logical force matching to eliminate answer choices quickly.
Identify the answer whose structure parallels the stimulus.
Employ conclusion and quantity matching to eliminate non-parallel choices efficiently.
Explain the main ideas and terminology related to Parallel Reasoning Questions.

Understanding the Components of an Argument

Before we delve into parallel reasoning questions, it’s important to revisit what makes up a logical argument: premises and conclusions.

Premises and Conclusions

An argument typically consists of:

Premises: Statements that provide support or evidence for a conclusion.
Conclusion: The statement that the premises aim to support.

For example, consider the following argument:

Premise: All mammals are warm-blooded.
Premise: All humans are mammals.
Conclusion: Therefore, all humans are warm-blooded.

In this argument:

The premises are “All mammals are warm-blooded” and “All humans are mammals.”
The conclusion is “Therefore, all humans are warm-blooded.”

Identifying Argument Structure

The structure can be broken down into logical forms. The general structure of the example above is:

If A, then B; A; therefore, B.

Knowing this structure allows us to apply it to other arguments. For parallel reasoning questions, we will look for answer choices that replicate this logical form.

Parallel Reasoning Questions Explained

Parallel reasoning questions are suited to test your ability to apply this concept. The direction often reads as, "Which one of the following arguments is most similar in logical structure to the argument above?"

Steps to Solve Parallel Reasoning Questions

Identify the Conclusion: Determine what the main conclusion of the argument is.
Identify the Premises: Identify the premises that support this conclusion.
Determine the Logical Form: Rewrite the argument in its structural format.
Evaluate the Answer Choices: Look for answer choices that replicate this structure.

Example of a Parallel Reasoning Question

Stimulus:

All dogs are animals.

All poodles are dogs.

Therefore, all poodles are animals.

Structure:

If A, then B; C; therefore, B.

Answer Choices:

A. All birds are animals.

All sparrows are birds.

Therefore, all sparrows are animals.

B. Some fish can swim.

All dolphins are fish.

Therefore, some dolphins can swim.

C. All mammals are warm-blooded.

All cats are mammals.

Therefore, all cats are warm-blooded.

D. Some reptiles lay eggs.

Some turtles are reptiles.

Therefore, some turtles lay eggs.

Analysis of Answer Choices

A follows the same structure as the original argument. If all birds are animals (A), and all sparrows are birds (C), then all sparrows are animals (B). This is a correct parallel reasoning match.
B has a different form, which concludes something about dolphins without matching the premises' structure.
C is also a valid argument but it does not match the structure as it talks about totality, rather than the necessity of argumentation.
D makes a broader statement, which shifts from the absolute conclusion drawn in the original prompt.

Thus, the correct answer is A.

Tips for Recognizing Logical Structures

Here are a few tips to help you recognize and match logical structures effectively:

Look for keywords that indicate the conclusion (e.g., therefore, thus, hence) and premises (e.g., since, because).
Pay attention to the quantifiers used in the argument (e.g., all, some). They play a crucial role in determining the argument's strength and validity.
Understand common logical flaws to avoid choosing answers that replicate similar flawed structures.

Common Misconceptions

Misconception 1: All arguments with similar topics are parallel.

Truth: Parallel reasoning is about logical structure, not the subject matter. An argument about dogs is not the same as an argument about birds unless the formal structure is preserved.

Misconception 2: If an argument sounds correct, it must be parallel.

Truth: The soundness of arguments does not dictate parallelism in structure; logical form takes precedence.

Misconception 3: The length of an argument signifies its validity.

Truth: Both short and long arguments can be valid or flawed based entirely on their logical structure.

Conclusion

Parallel reasoning questions require practice to master. With the tools provided in this lesson, students, you can dissect arguments with precision and identify their structures. Focus on practicing with a variety of examples to sharpen your skills further. By employing logical force and conclusion matching techniques, you can speed up your answer selection process more effectively.

Study Notes

Parallel reasoning questions assess the ability to match logical structures.
Understand the components: premises and conclusions.
Identify argument forms: If A, then B; C; therefore, B.
Keep an eye out for keywords indicating logical structure.
Avoid common misconceptions related to argument topic and soundness.
Practice drawing parallels between varying arguments to develop efficiency and speed.