Lesson 7.1: Argument Structure: Evidence, Conclusion, Assumption

Introduction

In this lesson, students will learn about the fundamental elements that construct a logical argument. Understanding the argument's structure will enhance your ability to analyze and evaluate critical reasoning questions in the GMAT exam. The primary focus will be on identifying conclusions, evidence, and assumptions within arguments, which are essential components in dissecting logical expressions commonly found in verbal reasoning.

Learning Objectives

By the end of this lesson, students will be able to:

1. Identify the conclusion and the supporting evidence in an argument.
2. Recognize the unstated assumptions that link the evidence to the conclusion.
3. Separate premises from background information and counterpoints.
4. Decompose an argument into its logical components.
5. Pinpoint the conclusion even when it is not stated last.

Understanding Argument Structure

An argument is a series of statements wherein one or more statements (premises) are offered as reasons to support another statement (the conclusion). To evaluate an argument effectively, it is crucial to grasp its structure, which is usually composed of three main components: evidence, conclusion, and assumptions.

Evidence

Evidence consists of the premises that provide support for the conclusion. Premises can take various forms including facts, statistics, expert opinions, and anecdotes. They should be relevant and convincing enough to back up the claim made in the conclusion.

Example:

Consider the argument:

"Eating fruits and vegetables lowers the risk of chronic diseases. Therefore, everyone should increase their intake of fruits and vegetables."

In this case, the evidence is the assertion that eating fruits and vegetables lowers the risk of chronic diseases. This statement serves as support for the conclusion that everyone should increase their intake of these foods.

Conclusion

The conclusion is the claim that the argument seeks to establish. It is what the argument is trying to prove or persuade the audience to accept. Identifying the conclusion often involves looking for indicators such as the words "therefore," "thus," or "hence," although the conclusion may appear at any point in the argument.

Example:

Using the prior example again, the conclusion is that everyone should increase their intake of fruits and vegetables. This is what the argument is advocating based on the premise (evidence) provided.

Assumptions

Assumptions are the unstated premises that are necessary for the conclusion to logically follow from the evidence presented. These assumptions, while often overlooked, play a critical role in the strength of the argument. A flawed assumption can undermine the argument's validity.

Example:

Let’s analyze the argument:

"Eating fruits and vegetables lowers the risk of chronic diseases. Therefore, everyone should increase their intake of fruits and vegetables."

The unstated assumptions might include:

• All individuals can easily increase their intake of fruits and vegetables.
• Eating fruits and vegetables is the only or most effective means to lower the risk of chronic diseases.

Recognizing these assumptions is vital in evaluating the argument’s soundness.

Decomposing an Argument

To effectively decompose an argument, students should practice identifying its elements systematically. This involves reading the argument closely and noting key phrases that signal evidence and conclusions. Let's apply this method in a practical scenario:

Worked Example

Consider the following argument:

"Since the introduction of the new public transportation system, traffic congestion has decreased significantly. Therefore, the new transportation system is effective."

1. Identify the conclusion:

The conclusion is that the new transportation system is effective.

1. Identify the evidence:

The evidence supporting this conclusion is that traffic congestion has decreased significantly since the introduction of the system.

1. Identify assumptions:

Assumptions might include:

• Other factors are not contributing to the decrease in traffic congestion.
• The decrease in congestion is solely due to the new public transportation system rather than a general trend.

By breaking down the argument this way, students can better assess its validity and recognize any weaknesses.

Common Misconceptions

• Misconception 1: The conclusion always comes at the end of an argument.
• Clarification: Conclusions can appear at the beginning, middle, or end of an argument. It is essential to look for logical indicators rather than fixating on the position of the conclusion.
• Misconception 2: All evidence presented is valid and strong.
• Clarification: Not all evidence is equally compelling. Assess the credibility of the evidence by considering its source and relevance to the conclusion.

Conclusion

Understanding the structure of arguments is an essential skill for the GMAT verbal reasoning section. By identifying evidence, conclusions, and assumptions, students can analyze arguments more critically. This lesson provided insights into how to decompose arguments effectively, equipping you with the tools necessary for success.

Study Notes

• An argument comprises premises (evidence) and a conclusion.
• Evidence supports the conclusion but may require assumptions to be valid.
• Conclusions may not always be the last statement in an argument.
• Recognizing unstated assumptions enhances critical analysis of arguments.
• Misconceptions can hinder effective argument evaluation; always check positions and relevance of evidence.