Tutorial # 2. Informal Reasoning. Exercising the skills of reasoning

From Anne Thomson (2002) Critical Reasoning, Chapter 5

Summary: Assessing an argument

Analysing

1 Identify conclusion and reasons:
• look for ‘conclusion indicators’,
• look for ‘reason indicators’ and/or
• ask ‘What is the passage trying to get me to accept or believe?’
• ask ‘What reasons/evidence is it using in order to get me to believe this?’

2 Identify unstated assumptions:
• assumptions supporting basic reasons,
• assumptions functioning as additional reasons, assumptions functioning as intermediate conclusions,
• assumptions concerning the meanings of words,
• assumptions about analogous or comparable situations,
• assumptions concerning the appropriateness of a given explanation.

Evaluating

3 Evaluate truth of reasons and assumptions:
• how would you seek further information in order to help you to do this?

4 Assess the reliability of any authorities on whom the reasoning depends.

5 Is there any additional evidence which strengthens or weakens the conclusion?
• anything which may be true?
• anything which you know to be true?

6 Assess the plausibility of any explanation you have identified.

7 Assess the appropriateness of any analogies or comparisons you have identified.

8 Can you draw any conclusions from the passåge? If so, do they suggest that the reasoning in the passage is faulty?

9 Is any of the reasoning in the passage parallel with reasoning which you know to be flawed?

10 Do any of the reasons or assumptions embody a general principle? If so, evaluate it.

11 Is the conclusion well supported by the reasoning? If not, can you state the way in which the move from the reasons to the conclusion is flawed? Use your answers to questions 5 to 10 to help you to do this.