DM: Evaluating Arguments & Recognising Assumptions

Argument Evaluation Questions

These questions present an argument or claim and ask you to evaluate its strength, identify what strengthens or weakens it, or recognise the assumptions it relies upon.

Anatomy of an Argument

• Conclusion: The main claim being made
• Premises: The evidence or reasons offered in support
• Assumptions: Unstated beliefs that must be true for the argument to work
• Counterarguments: Reasons why the conclusion might be wrong

Evaluating Argument Strength

A strong argument has:

• Relevant premises that directly support the conclusion
• Sufficient evidence (not just one anecdote)
• Logical connection between premises and conclusion
• Acknowledgement of counterarguments

A weak argument has:

• Irrelevant premises (true but not connected to the conclusion)
• Logical fallacies (ad hominem, straw man, appeal to authority, etc.)
• Insufficient or biased evidence
• Unsupported leap from premises to conclusion

Recognising Assumptions

An assumption is an unstated premise that must be true for the argument to hold. To find assumptions:

1. Identify the conclusion and the stated premises
2. Ask: “What must be true for these premises to support this conclusion?”
3. The gap between the premises and the conclusion is the assumption

Example:
“Hospital X has the lowest readmission rate in the state. Therefore, Hospital X provides the best patient care.”
Assumption: Readmission rate is a valid and sufficient measure of patient care quality. (This ignores other factors like mortality rates, patient satisfaction, complexity of cases, etc.)

Strengthening vs Weakening

Strengthening: Information that makes the conclusion MORE likely to be true. Often this involves supporting an assumption or providing additional evidence.

Weakening: Information that makes the conclusion LESS likely to be true. Often this involves undermining an assumption, providing a counterexample, or suggesting an alternative explanation.

Irrelevant: Information that has no bearing on whether the conclusion is true or false, even if it is related to the topic.