Lesson 2.1: Premises, Conclusions, and Argument Structure

Introduction

In this lesson, we will dive deep into the foundational elements of arguments: premises and conclusions. Understanding how to identify these components is essential for effective critical reasoning, especially when approaching the LSAT. This section aims to equip you with the skills needed to deconstruct arguments systematically, discern their structure, and evaluate their soundness. By the end of the lesson, you should be able to:

Identify the main conclusion, subsidiary conclusions, and premises in compact arguments.
Recognize conclusion and premise indicator words and structural cues.
Locate the main conclusion of an argument reliably, even when it is unstated or buried within the text.
Map how premises support a conclusion within single arguments.
Explain the main ideas and terminology associated with premises and conclusions.

Understanding Arguments

An argument consists of a series of statements, where some statements (premises) are offered as reasons to support another statement (the conclusion). To develop clear critical reasoning skills, we first need to define our key terms:

Premise: A statement that provides support or evidence for the conclusion. Premises are the building blocks of an argument.
Conclusion: The statement that the premises support. It is what the argument is trying to prove or establish.
Assumption: An unstated belief that must be true for the conclusion to hold based on the premises.

Understanding how these elements work together allows for a clearer analysis of any argument presented.

Example 1

Argument: All humans are mortal. Socrates is a human. Therefore, Socrates is mortal.

Premises: 1) All humans are mortal, 2) Socrates is a human.

Conclusion: Socrates is mortal.

In this example, the first two statements are premises that provide evidence, while the final statement is a conclusion drawn from the premises. Notice how premises are factual statements that lead logically to the conclusion.

Identifying Premises and Conclusions

One key skill in critical reasoning is the ability to identify which statements are premises and which are the conclusion(s). Often, arguments in LSAT questions will employ indicator words that signal the relationship among the statements.

Here are some common indicators:

Conclusion indicators: Therefore, Thus, Consequently, It follows that, Hence, For this reason.
Premise indicators: Because, Since, Given that, For, As, Inasmuch as.

Example 2

Argument: Since the weather is nice, we should go to the park. Therefore, we will have a picnic.

Premise: The weather is nice.
Conclusion: We will have a picnic.

Practice Exercise

Read the following argument and identify its premises and conclusion:

Argument: The city has seen an increase in crime. Because of that, the mayor has proposed new policing measures. Thus, it is essential for the public to be informed about these changes.

Premises: The city has seen an increase in crime; the mayor has proposed new policing measures.
Conclusion: The public should be informed about the changes.

Mapping Premises to Conclusions

Once you can identify premises and conclusions, the next step is to understand how they relate. It is crucial to map how the premises support the conclusion. The structure of an argument can be visualized as a flow chart: the premises provide the foundation, while the conclusion stands above them, supported by the evidence.

Example 3

Argument:

1) Studying improves performance.

2) Maria has studied every day.

Therefore,

3) Maria will perform well on the exam.

Here, we can see:

Premise 1: Studying improves performance.
Premise 2: Maria has studied every day.
Conclusion: Maria will perform well on the exam.

The connection between the premises and the conclusion can be intuitively understood. The conclusion is a logical result of the information provided in the premises. Thus, if both premises are accepted as true, the conclusion must also logically follow.

Common Misconceptions

One common mistake is to confuse the conclusion with premises, especially when the conclusion is implied rather than explicitly stated. It is also easy to overlook assumptions; always ask yourself what assumptions underlie the premises you accept as true.

Conclusion

In this lesson, we learned that an argument's structure is composed of premises that support conclusions. We discussed how to identify these components using indicators and reviewed how to visualize the relationships between them. Mastering the identification of premises and conclusions not only improves your critical reasoning skills but also prepares you for more complex argument forms later in your LSAT preparation.

Study Notes

An argument consists of premises (evidence) and a conclusion.
Conclusions are what the argument seeks to prove, while premises support that conclusion.
Common conclusion indicators: Therefore, Thus, Consequently.
Common premise indicators: Because, Since, Given that.
It is essential to map how premises support conclusions to understand an argument fully.
Watch for implicit conclusions and assumptions that may not be explicitly stated in the argument.