Lesson 2.2: Testing Whether Reasons Support the Conclusion

Introduction

In this lesson, students will learn how to evaluate arguments effectively by examining whether the reasons provided actually support the conclusions drawn. An argument, whether in academic writing or everyday discussion, is built on claims made by the author, supported by reasons and evidence. Understanding the strength and relevance of these reasons is crucial for critical reading and reasoning. The objectives of this lesson include:

• Identifying the two fundamental questions every argument faces: Are the reasons true, and do they support the conclusion?
• Distinguishing between strong, weak, and irrelevant support for a conclusion.
• Recognizing gaps and leaps between reasons and conclusions.
• Identifying the necessary truths for an argument to hold.
• Judging the extent to which a conclusion is justified based on available reasons.

What Makes Up an Argument?

An argument consists of several key components: a claim, reasons, evidence, and sometimes assumptions. The claim is the statement that the author is trying to convince you is true. Reasons are the statements that provide support for the claim. Evidence includes the facts, data, or examples that bolster the reasons. Understanding these components is vital for evaluating the argument.

Claim: A statement or assertion.

Example: "Climate change is primarily caused by human activity."

Reason: A statement that supports the claim.

Example: "Human activities, such as burning fossil fuels, increase carbon dioxide levels in the atmosphere."

Evidence: Information that backs up the reasons.

Example: "According to NASA, atmospheric CO2 levels have risen 40% since the Industrial Revolution."

Knowing these elements helps us dissect an argument and examine whether it holds up under scrutiny. Now let's explore the key questions that can assess the quality of an argument.

Are the Reasons True?

Determining if the reasons presented in an argument are true is the first step. Sometimes, the reasons may seem persuasive but can be based on faulty information. This makes it essential to evaluate the credibility of the sources being cited and check the facts.

Example: Evaluating Truthfulness

Argument: "Eating carrots improves your eyesight because they are rich in vitamin A."

1. Claim: Eating carrots improves eyesight.
2. Reason: Carrots are high in vitamin A.
3. Evidence: Vitamin A is known to contribute to vision.

Step 1: Verify the truth of the reason.

• Vitamin A does assist in maintaining healthy vision, especially in dim light. This part of the reasoning is true.

Step 2: Consider if the evidence truly supports the reason.

• While the reason is true, it oversimplifies the relationship between eating carrots and improved eyesight. Other factors contribute to vision health. Thus, the argument fails to acknowledge these additional elements.

Common Misconceptions

A common misconception is that if a reason is true, it automatically supports the conclusion. However, the relationship must also be logical and relevant. Just because vitamins are good for health does not mean eating one food exclusively can solve all health issues.

Do the Reasons Support the Conclusion?

To determine if the reasons genuinely support the conclusion, consider the strength and relevance of each reason.

Strong, Weak, and Irrelevant Support

• Strong Support: The reasons are directly related to the conclusion, and they provide solid evidence that strengthens the claim.

Example: If an author claims that exercise improves mental health and provides studies showing that regular exercise reduces anxiety and depression significantly, the reasons strongly support the conclusion.

• Weak Support: The reasons may be true, but they do not provide convincing evidence for the conclusion.

Example: "Reading books can reduce stress; therefore, all readers will be happier." Although reading is calming, it does not guarantee happiness for every reader.

• Irrelevant Support: The reasons provided do not connect logically with the conclusion.

Example: "The economy is growing; therefore, we should invest in renewable energy." The growth of the economy does not directly translate to the benefits of investing in a specific sector unless further justification is provided.

Example: Evaluating Support

Argument: "Implementing a four-day work week will increase productivity because employees will be less stressed."

1. Claim: A four-day work week increases productivity.
2. Reason: Employees will experience less stress.
3. Evidence: Studies show a correlation between reduced work stress and increased productivity.

Evaluation:

• Is the reason true? Yes, reducing stress can lead to better performance.
• Does it strongly support the conclusion? Partially, as other factors also impact productivity. Thus, while there is merit to the claim, the argument could be strengthened by providing more reasons or addressing potential downsides of the change.

Recognizing Gaps and Leaps

An argument may have gaps where the reasoning fails to connect logically to the conclusion. Recognizing these gaps helps in critically assessing the argument.

Example: Noting Leaps in Reasoning

Argument: "All successful entrepreneurs are educated; therefore, education leads to success."

1. Claim: Education leads to entrepreneurial success.
2. Reason: All successful entrepreneurs have education.

In this case, the leap in reasoning is significant. While the premises may be true, other factors contribute to success, such as experience, networking, and critical thinking skills. Therefore, the connection made is flawed.

What Needs to be True for the Argument to Hold?

To evaluate the robustness of an argument, it is essential to ask what conditions must exist for the premises to support the conclusion genuinely.

Example: Conditions for Validity

Argument: "Drinking green tea helps with weight loss; therefore, one should consume green tea daily."

• Necessary truths: Consuming green tea needs to be effective in promoting weight loss, and one needs to consume it in sufficient amounts.
• Critical thinking: While drinking green tea may help, it should not be the only action considered for weight loss, highlighting how one must also manage diet and exercise.

Conclusion

In summary, understanding whether the reasons support the conclusion is critical for evaluating arguments. Learning to ask the right questions, recognize gaps in reasoning, and assess the strength and relevance of evidence helps build a sophisticated approach to critical reading. By practicing these skills, students will be better equipped to navigate the sea of information encountered in academic and everyday contexts.

Study Notes

• An argument consists of a claim, reasons, and evidence.
• First question: Are the reasons true?
• Second question: Do the reasons support the conclusion?
• Strong support is directly related to the conclusion; weak support lacks persuasive strength; irrelevant support does not connect logically.
• Recognizing gaps in reasoning is crucial for critical thinking.
• Understanding necessary conditions for arguments strengthens overall evaluation.