Rank 8 by frequency | 215 questions in corpus (4.7% of all questions)
A Sufficient Assumption question presents an argument with a logical gap and asks which answer choice, if assumed, would make the conclusion follow with logical certainty. Unlike Necessary Assumption (which asks for the minimum the argument needs), Sufficient Assumption asks for an answer that completely closes the gap and makes the argument airtight – deductively valid. The correct answer is a premise that, when added to the existing premises, guarantees the conclusion. These questions are sometimes called "Justify the Conclusion" questions.
Identify the one answer that would completely solve the gap between the conclusion and the evidence – the answer that, if added as a premise, makes the conclusion logically certain. The relationship is: Premises + Correct Answer = Conclusion MUST be true.
Your ability to identify what single additional premise would make an argument deductively valid. This often requires formal logic skills – recognizing conditional relationships, missing links in chains, quantifier logic, and the ability to spot "new concepts" in conclusions that lack support in the premises.
1. Premises establish a logical foundation. The stimulus presents one or more premises, often using conditional language ("if...then"), universal claims ("all X are Y"), or causal statements. These premises create the beginning of a logical chain.
2. The conclusion makes a claim that goes beyond what the premises prove. The conclusion introduces a logical leap – it asserts something that would only follow if an unstated assumption were true. Critically, the conclusion often contains a "new concept" or "rogue element" that appears nowhere in the premises.
The conclusion contains at least one element – a concept, term, or idea – that is NOT directly supported by the premises. This "new element in the conclusion" is the telltale sign of the gap. The premises talk about A and B; the conclusion talks about A and C. The missing link is B->C (or some relationship that connects B to C).
The formal structure is:
The gap in a Sufficient Assumption question is the single missing premise that would make the argument deductively valid. Its characteristics:
Correct answer: - When added to the existing premises, the conclusion follows with deductive certainty - Bridges the specific gap between premises and conclusion - Often contains strong, absolute language ("all," "every," "no," "always," "only") because making an argument airtight typically requires strong claims - May contain information beyond what is strictly necessary (it just has to be sufficient, not minimal) - Frequently takes the form of a conditional statement that supplies the missing link in a logical chain - May be worded as the contrapositive of what you would naturally predict
Incorrect answers: - Premise boosters: Strengthen existing premises by explaining why they are true, but do not connect premises to the conclusion. They make the evidence more credible without bridging the gap. - Detail creep: Introduce tangential information unrelated to the logical chain between premises and conclusion. - Insufficient strengtheners: Make the argument somewhat more plausible without making it airtight. They use weak language ("some," "many," "might," "could") where absolute language is needed. - Reversed conditionals: State the logical relationship backward (affirming the consequent or denying the antecedent). - Wrong new concept addressed: Address a different concept than the specific "new element" that appears in the conclusion but not the premises. - Restaters: Merely rephrase information already stated in the premises without adding anything new.
Structure: The premises and conclusion form a conditional chain with a missing link. The correct answer supplies the missing conditional to complete the chain.
Example pattern: `` Premise 1: If A, then B Premise 2: If C, then D Conclusion: If A, then D Gap: If B, then C (or equivalently: If not C, then not B) ``
Structure: The conclusion introduces a concept, term, or idea that appears nowhere in the premises. The correct answer connects an element from the premises to this new concept.
Example pattern: `` Premises discuss: What made Shakespeare "different from his contemporaries" Conclusion claims: What is "of most interest" about Shakespeare Gap: Being "different from contemporaries" = being "of most interest" ``
Structure: The premises use universal or existential quantifiers ("all," "some," "no," "most"), and the conclusion makes a claim that requires a different quantifier relationship.
Example pattern: `` Premise: All members of group X have property Y Premise: Z is being considered for group X Conclusion: Z has property Y Gap: Z is a member of group X ``
Structure: The conclusion is a negative claim, and the correct answer requires applying the contrapositive of a premise or constructing a chain that involves negation.
Example pattern: `` Premise: If our competitor closes, our suppliers go bankrupt Conclusion: For us to stay in business, our competitor must stay in business Gap: If our suppliers go bankrupt, we cannot stay in business (contrapositive chain: we stay -> suppliers survive -> competitor stays) ``
1. Bridges the specific gap. The correct answer, when combined with the existing premises, makes the conclusion follow with certainty. It is the missing piece that completes the logical puzzle.
2. Often uses strong/absolute language. Words like "all," "every," "no," "always," "none," "only," and "must" are actually desirable in correct answers for Sufficient Assumption questions. (This is the opposite of Necessary Assumption questions, where extreme language is a red flag.) The argument needs to be made airtight, and that typically requires absolute claims.
1. Premise boosters: Explain why an existing premise is true or provide additional support for a premise, but do not connect the premises to the conclusion. "The study was conducted using rigorous methodology" strengthens a premise but does not bridge the gap to the conclusion.
2. Detail creep / tangential information: Introduce new facts or concepts that are related to the topic but do not address the specific gap. They add information about the world of the stimulus without completing the logical chain.
`` Existing Premises + Correct Answer => Conclusion (necessarily true) ``
The correct answer is a sufficient condition for the conclusion's truth (given the premises). The test: if you accept all existing premises AND the correct answer as true, can you imagine any scenario where the conclusion is false? If no – the answer is correct. If yes – the answer is insufficient.
1. Conditional chain with missing link: The most frequent pattern. Premises form a chain A->B->C; conclusion claims A->D; you need C->D.
2. Causal argument needing a bridge: Premises establish cause-and-effect for part of a chain; conclusion extends the chain further; the missing assumption connects the known effect to the claimed result.
1. Multiple conditional premises creating information overload: The stimulus contains 3-5 conditional statements. You must diagram them, identify contrapositives, link them into a chain, and find the missing link. This is the classic "curve-breaker" Sufficient Assumption question.
2. Contrapositive correct answer: The correct answer is the contrapositive of the obvious bridge, requiring an extra translation step.
1. Identify the conclusion. Look for conclusion indicators ("therefore," "thus," "so," "hence") or the main claim. This is critical because you need to know what must be guaranteed.
2. Identify all premises. Map out every piece of evidence or given information.
Sufficient Assumption vs. Necessary Assumption:
| Sufficient Assumption | Necessary Assumption | |—|—| | Makes the argument deductively valid | Must be true for the argument to work, but may not make it valid | | Adding it guarantees the conclusion | Removing it (negating it) destroys the argument | | Extreme/absolute language is often correct | Extreme language is often wrong | | "The conclusion follows logically if..." | "The argument depends on assuming..." or "requires" | | Correct answer can be broader than needed | Correct answer must be precisely what is needed – no extra | | Test: Premises + answer = conclusion must be true? | Test: Negate the answer – does the argument fall apart? |
Assumption & Support Skills – Identify what an argument needs or what helps/hurts it.