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Match an abstract criticism to the exact unsupported move in an argument.
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
Identify a reasoning error without confusing a false premise, an unwelcome conclusion or an error the author never made with the actual flaw.
The previous lessons asked which addition would improve or damage support. A flaw question asks you to describe a weakness already present. Identify the conclusion and state what the premises actually establish before looking for a name or an abstract description.
| Term | What it means |
|---|---|
| Converse error | Inferring A from B when only if A then B has been established. |
| Composition error | Transferring a property of parts to a combined whole without justification. |
| False dilemma | Treating an incomplete list of alternatives as exhaustive. |
| Circular support | Using a premise that already assumes the conclusion to be established. |
A flaw is a defect in the reasoning from premises to conclusion. You do not need to know a Latin label to identify it. If every registered driver has a permit and a person has a permit, the argument cannot automatically conclude that the person is registered. The rule permits permit-holders who are not registered drivers. Describing that reversal is more useful than merely saying the logic is bad.
A correct criticism must fit both the form and the force of the inference. An answer about a biased sample cannot be right when the argument never generalizes from a sample. An answer about circularity must identify a premise that assumes the conclusion, not just a repeated word. An answer about personal motives must match a dismissal based on those motives rather than an independent criticism of the evidence.
Start with a plain-language prediction: the author treats a requirement as a guarantee, transfers a property from parts to a whole, assumes only two possibilities, or treats missing evidence as positive proof. Then compare that prediction with each choice. The wording of a correct answer may be abstract, but you should be able to replace each abstract term with a specific claim in the passage.
Another way: picture
Put the premise and conclusion in separate boxes. Label the move between them: all to some, part to whole, association to cause, requirement to guarantee, or not proved to disproved. Inspect that move, not the attractiveness of either box.
Another way: steps
State what is known; state what is concluded; construct a case exposing the gap; describe the unsupported move; match every part of the criticism to the passage.
A criticism becomes clearer when you can construct a situation in which the premises hold but the conclusion fails. For the portfolio example, imagine an applicant who submits a portfolio and is then rejected. Every shortlisted applicant can still have submitted one. The case demonstrates exactly why the necessary condition does not guarantee the outcome. You do not need to show that this particular applicant was rejected in reality; the unexcluded possibility is enough to reveal the deductive gap.
For an argument based on missing records, imagine that the event occurred but the surviving writers did not mention it. The premises about documentary silence remain true. If the author had instead established complete, accurate records of every relevant event, the criticism would need reconsideration. Diagnose the argument actually supplied, including any safeguards it contains. A stock objection is not automatically applicable just because an argument concerns historical evidence.
Be equally careful with causal language. Saying that a comparison fails to rule out a rival cause is not the same as saying the rival cause has been established. A correct flaw description often identifies what the evidence cannot distinguish. A wrong answer may exaggerate this into a claim that the proposed cause is impossible or that the conclusion has been disproved. Match the criticism's strength to the defect you can demonstrate.
Abstract options frequently contain several commitments. An answer might say that an argument relies on an unrepresentative sample and also assumes everyone in the population shares one view. The first part may fit while the second does not. Evaluate the whole description. One accurate phrase cannot rescue a materially inaccurate addition. Replace sample, population, property and conclusion with the passage's actual terms to see whether the complete description still makes sense.
If A implies B, B alone does not imply A. Not A alone does not imply not B. The valid negative route is not B to not A. Translate ordinary language carefully before diagnosing a reversal, especially when only if or unless changes the apparent order of phrases. A diagnosis based on a mistranslated rule is itself a reasoning error.
Scope changes can be just as important. Some is not most, most is not all, and a statement about every individual need not hold of the group as a combined object. Every component can be inexpensive while the assembled collection is expensive. Yet not every parts-to-whole inference fails: if each tile is ceramic, a mural made only of those tiles has a different kind of property from their combined weight. Explain why the specific property does not transfer.
If no evidence of a defect has been found, the warranted claim may be only that no defect has yet been demonstrated. Whether an absence of evidence supports an absence depends on the search's sensitivity and coverage. A careful inspection could make a difference; merely saying nobody has proved danger does not describe such an inspection. The flaw is the unsupported leap, not a rule that negative evidence can never matter.
Similarly, correlation can be compatible with a causal explanation without establishing it. A flaw answer should say that the author fails to exclude or consider another explanation when that is the actual move. Do not overstate the criticism as showing that causation is impossible. The conclusion may be true despite the inadequate reason.
A source's incentives can give a reason to investigate reliability. They do not automatically refute the source's claim. A criticism that points to manipulated measurements is different from one that simply points to ambition or dislike. Read whether the argument provides an independent evidential defect.
For a false dilemma, identify a possible alternative outside the offered pair. For an equivocation, locate the changed meaning rather than merely a repeated term. For a circular argument, show how the premise assumes what was to be established. These checks keep familiar flaw labels from becoming guesses. The best description should account for the argument as written without adding a new premise or silently strengthening its conclusion.
An editorial may accuse a proposal of poor logic. Translate the criticism into a testable description: which premise, which conclusion and which unsupported transition? If those parts cannot be located, the criticism may be a label without analysis. Conversely, a simple countercase can expose a flaw even when you cannot recall a technical name.
The practice records grade a bounded match between an argument and a description. They do not judge an original critique. Review a wrong answer by identifying the feature it would require and checking whether that feature is present. For example, a composition criticism needs a move from parts to a combined whole; an appeal-to-popularity criticism needs popularity used as evidence for truth or merit. This habit helps prevent broad terms from becoming interchangeable. On later practice, retrieve the unsupported move before reading the option wording.
Do not call an argument flawed merely because its conclusion is unpopular, and do not select a criticism whose sample, motive, cause or ambiguity never appears in the passage.
Read the passage and question.
Every shortlisted applicant submitted a portfolio. Lina submitted a portfolio. Therefore Lina was shortlisted.
Which criticism identifies the flaw?
Match required and sufficient to the actual portfolio-to-shortlist direction.
Compare the five proposed answers.
1: Submitting a portfolio is treated as sufficient for shortlisting when it is only stated to be required. 2: The argument attacks Lina's motives. 3: It infers causation from a survey. 4: It treats a whole's weight as a part's weight. 5: It concludes that no portfolios exist.
Apply the question's test to each option; do not choose solely by shared vocabulary.
Explain the best answer.
Submitting a portfolio is treated as sufficient for shortlisting when it is only stated to be required.
The rule allows applicants who submit portfolios but are not shortlisted.
Account for every rejected answer.
2: No motive is mentioned or used to dismiss a claim. 3: No survey or causal attribution appears. 4: There is no quantitative parts relationship. 5: The argument explicitly says Lina submitted one.
Each rejection identifies a specific mismatch with the passage or task.
Read the passage and question.
No surviving diary mentions a village market on Tuesdays. Therefore the village never held a Tuesday market.
Which criticism most directly identifies the problem?
The issue is the completeness of the evidence, not whether diaries are always reliable or always useless.
Compare the five proposed answers.
1: It assumes the surviving diaries would mention every Tuesday market if any existed. 2: It assumes diaries can never be evidence. 3: It proves Tuesday markets existed elsewhere. 4: It transfers a price from one market to another. 5: It gives two conflicting dates for one diary.
Apply the question's test to each option; do not choose solely by shared vocabulary.
Explain the best answer.
It assumes the surviving diaries would mention every Tuesday market if any existed.
Without that coverage assumption, documentary silence need not establish that the event never occurred.
Account for every rejected answer.
2: The argument relies on diaries rather than rejecting all diary evidence. 3: No other village is discussed. 4: There is no price comparison. 5: No conflicting dates are stated.
Each rejection identifies a specific mismatch with the passage or task.
Read the passage and question.
A club says it must either hire a full-time manager or abandon its weekend events. It cannot afford a full-time manager, so it must abandon the events.
Which criticism best exposes the flaw?
The deduction from an exhaustive either-or could be valid; the flaw is treating an unsupported list as exhaustive.
Compare the five proposed answers.
1: It assumes those are the only options without considering part-time or shared arrangements. 2: It ignores that full-time work is always free. 3: It mistakes a conclusion for a survey result. 4: It assumes all events already have a manager. 5: It attacks weekend visitors personally.
Apply the question's test to each option; do not choose solely by shared vocabulary.
Explain the best answer.
It assumes those are the only options without considering part-time or shared arrangements.
The argument's exclusion step works only if the alternatives exhaust the available options.
Account for every rejected answer.
2: That unsupported claim is not a legitimate criticism of the reasoning. 3: No survey is offered. 4: The passage does not require or state that premise. 5: Visitors' character is not discussed.
Each rejection identifies a specific mismatch with the passage or task.
Check the difficult boundary.
A possible third arrangement exposes the gap without proving that any particular arrangement will succeed.
This last check preserves the exact strength and scope of the answer rather than turning it into a broader claim.
Locate the transfer.
Each suitcase weighs less than the airline's total baggage allowance; therefore all the suitcases together weigh less than that allowance.
The move is from individual weights to combined weight.
Describe the error.
Several individually light suitcases can have a combined weight above the allowance.
The same upper bound does not automatically apply to a sum.
Reject a mismatched label.
Every certified guide has completed training. Pavel completed training, so Pavel must be a certified guide. Which description identifies the reasoning error?
Every tile in a mural weighs less than a kilogram. Therefore the complete mural weighs less than a kilogram. Which flaw best describes the inference?
Every approved application includes a signature. Lin's application includes a signature, so it must be approved. What is the flaw?
Each tile in a mosaic weighs less than a kilogram. Therefore the completed mosaic weighs less than a kilogram. Which error occurs?
Two proposals for a plaza are a fountain and a garden. The fountain is too costly. Therefore a garden is the only possible use of the plaza. What makes the reasoning defective?
A critic's proposal to improve a city's bus routes should be rejected because the critic once failed a driving test. Which flaw is most apparent?
A park has more visitors and more litter on weekends than on weekdays. Therefore attracting visitors is the only cause of litter. What is the main flaw?
No one has shown that the old tunnel is unsafe. Therefore it has been shown to be safe. Which flaw best describes the reasoning?
A bakery moves its proofing trays to a temperature-controlled cabinet and subsequently fewer loaves collapse. During the same period it also begins using a stronger flour. A coordinator concludes that the intervention caused the improvement, arguing that stable proofing temperature prevents excessive expansion. What is the main limitation of the coordinator's inference?
A coastal rescue station adds reflective markers to its landing route and subsequently crews reach the dock faster at night. During the same period it also introduces a navigation refresher course. A coordinator concludes that the intervention caused the improvement, arguing that markers make the approach easier to identify in darkness. What is the main limitation of the coordinator's inference?
A councilor says a noise study should be ignored because its author hopes to gain publicity. No error in the study's methods or measurements is identified. Which criticism best targets the reasoning?
Answer three reserved questions without hints. These cases are separate from lesson practice.
A committee found no evidence that a proposed tunnel would damage the old well. Therefore the tunnel certainly cannot damage the well. What is the flaw?
Most members of an orchestra own bicycles. Most members of the orchestra speak Spanish. Therefore at least one member does both. How should the reasoning be evaluated?
Either the theater replaces every seat this year or it does nothing to improve comfort. Replacing every seat is too expensive, so it can do nothing to improve comfort. Which criticism most directly exposes the flaw?
Tomorrow, translate a flawed argument into its premise-to-conclusion move. Recall the difference between a reversed rule, a parts-to-whole mistake and absence of evidence. Next, draw supported inferences without repairing the premises.
14. Keep the property straight, step 3
This is not a biased-survey problem because no sampled opinion is generalized.
A criticism must fit the inference actually present.