Unit quiz: Validity, soundness, and the fallacies that actually persuade

Check understanding, separately from reading

5 questions · 80% to pass · no timer. This quiz checks the lessons in this unit. These authored questions assess recognition and application of the taught distinctions, not professional qualification. You may review the lessons and retry. Repeat attempts reuse the question bank; a remembered answer is not proof of transfer to a new situation.

Saving a lesson records reading only. Previous lesson completions have not been converted into passing scores. You can continue reading without a pass; the assessment remains unpassed.

Question 1

A committee rejects a proposal with the reasoning: 'If the pilot programme had worked, participation would have risen, and participation rose, so the pilot worked.' A second member objects that the conclusion does not follow. Which assessment is correct, and what does it tell you about the argument's premises?The inference is invalid because it affirms the consequent, and the premises may all be true and even the conclusion true while the argument transmits no supportThe inference is valid, so the argument is sound if participation did in fact rise and would in fact have risen had the pilot worked

Question 2

A reader responds to a newspaper column on housing supply by saying that the author's claim is undermined by the fact that he owns several rental properties. Assess this response using the level's treatment of fallacies and of credibility.The response is an ad hominem attack and is therefore fallacious regardless of the subject under discussion, since a speaker's circumstances never bear on the truth of a claimWhether the response is a fallacy depends on what is at issue: if the question is the author's credibility or the presence of a conflict of interest, the fact is directly relevant, whereas if it is offered as a reason the claim is false it substitutes an attack for an argument

Question 3

An author defends a view of distributive obligation by describing a hypothetical society in which no one can plausibly claim to have earned their talents. A critic replies that the scenario is impossible. Evaluate the exchange.The reply engages a premise the argument need not rely on, since the thought experiment can function as a reductio of a claim about entitlement or a device for making a commitment visible rather than as an assertion that the scenario occursThe reply is decisive, because describing an impossible scenario cannot yield any conclusion about obligations in the actual world

Question 4

A researcher argues that a species of insect feels pain because its behaviour resembles the behaviour of vertebrates known to feel pain, and because blocking a specific neural pathway abolishes the behaviour. Identify what each strand of the argument is doing and where the weaker strand lies.Both strands are forms of the argument from analogy, so each depends on the single case of human experience and they stand or fall togetherThe resemblance claim is an argument from analogy with a thin comparative basis, while the intervention result supports the explanatory inference that pain best accounts for the behaviour and its abolition, so the intervention strand carries more weight

Question 5

A patient is advised by a specialist to change treatment immediately, and she has read an article suggesting the opposite. She wonders whether she may take the specialist's word over her own reading. What does the level's material on testimony identify as the crux?Whether the specialist is an epistemic authority in the relevant domain and whether authority preempts the patient's own reasoning or merely enters it as strong evidenceWhether the patient has positive non-testimonial reasons for thinking the specialist reliable, since without such reasons belief is unjustified

Continuing does not mark this assessment passed.

Progress stays in this browser, on this device—not an account or cloud backup. Clearing browser data removes it. Visits never count as study. Previous untimed legacy completions are not invented as study days.