How arguments work

An argument is not just a disagreement. It is a conclusion supported by one or more reasons. To judge an argument fairly, first map what it is saying. Then test whether the reasons are acceptable, relevant, and strong enough.

The vocabulary

Claim
A statement someone wants an audience to accept.
Conclusion
The main claim the argument is trying to establish.
Reason or premise
A statement offered in support of the conclusion.
Evidence
Information used to show that a reason or claim is accurate, such as observations, data, examples, expert findings, records, or reliable testimony.
Assumption
An unstated idea the argument needs in order to work.
Counterargument
A reason to question, limit, or reject the conclusion.
Rebuttal
A response to a counterargument.

A worked argument map

The school should add one shaded outdoor table because students currently have few places to read outside, shade reduces heat exposure, and the table could be used during lunch and class activities.
Mapping the argument into parts
PartIn this argument
Conclusion The school should add one shaded outdoor table.
Reason 1 Students have few outdoor reading spaces.
Reason 2 Shade reduces heat exposure.
Reason 3 The table has more than one use.
Evidence needed A map of current seating, temperature or shade information, student-use data, cost, and maintenance needs.
Assumption The benefits are worth the cost and space.
Possible counterargument Another campus need may have higher priority.

Three tests for support

Every reason should pass all three before it can carry a conclusion.

Acceptable

Is the reason believable, accurate, and fairly stated?

Relevant

Does the reason actually bear on the conclusion?

Sufficient

Is there enough support for a conclusion this broad and certain?

Reason → [acceptable?] → [relevant?] → [sufficient?] → Conclusion

Where fallacies enter the map

Mini exercise

The school should buy this learning game because every student online says it is amazing.
  1. What is the conclusion?
  2. What evidence is offered?
  3. Does popularity establish learning value?
  4. What evidence would improve the argument?
Repaired: The school should test the game with a small group because it aligns with the unit goals, includes useful feedback, meets accessibility requirements, and performed well in independent classroom trials.

Ready to analyze one? Start the project guide or browse the 15 fallacies.