Truth and support are different questions
A valid deductive argument cannot have true premises and a false conclusion. Validity concerns that relationship, not whether the actual premises are true. A sound argument is valid and has true premises. An argument may accidentally reach a true conclusion through invalid reasoning, just as a valid form can carry false assumptions.
Much ordinary reasoning is probabilistic. Evidence may make a conclusion more credible without guaranteeing it. A well-conducted sample can support a population estimate while leaving uncertainty. Evaluate that reasoning by the quality and strength of the support, rather than declaring every non-deductive argument worthless.
Match the force of the answer to the evidence
For a must-follow inference, test whether all the stated information could be true while the proposed inference is false. If so, it is not required. A most-supported inference asks for the strongest available support among the choices, and may permit cautious probabilistic language. Read the question’s standard before importing your own.
A strengthen answer adds support; a weaken answer reduces it. Neither must prove or disprove the conclusion. Target the connection between evidence and conclusion: a credible alternative cause can weaken a causal claim even if that claim might still be true. An emotionally appealing fact about the topic may do neither.
Find the gap at the right level
A generalization from one successful event to every event goes beyond its evidence. A recommendation adds a further step: descriptive facts alone do not determine what ought to be done without some evaluative premise. Making that premise explicit helps people locate a genuine disagreement about goals or priorities.
Before selecting an answer, distinguish the conclusion itself from the author’s case for it. Showing that a speaker is unreliable can sometimes affect how much to trust testimony. It does not, by itself, establish that every proposition the speaker asserts is false.
Worked example
Four evening workshops sold out. The organizer concludes that moving every workshop to the evening will increase total attendance.
- Evidence
- Four particular evening workshops were full.
- What remains open
- They may have had unusually popular speakers, small rooms, or audiences already served by daytime sessions.
- A strengthening fact
- Comparable evening and daytime workshops with the same topics repeatedly attract more attendees in the evening. This improves the comparison without proving that every move will succeed.
- A cautious inference
- Some evening workshops attracted enough demand to fill their available places. The evidence alone does not establish total citywide demand.
Check your understanding
Take it into practice
Ask whether the exercise needs certainty, probable support, or merely a change in the strength of the argument.