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Every LNAT Section A question — without exception — requires you to engage with the structure of an argument. Whether the question asks for the main conclusion, an assumption, the meaning of a phrase in context, or the author's tone, you cannot answer correctly without understanding how the argument is built. This lesson revisits the fundamental anatomy of an argument with the depth and rigour needed for the most demanding LNAT questions.
In everyday language, an "argument" means a disagreement. In critical thinking — and in the LNAT — an argument is something quite specific:
An argument is a set of claims in which one or more claims (the premises) are offered as reasons to accept another claim (the conclusion).
This definition contains three essential elements:
| Element | Role | Example |
|---|---|---|
| Premises | The reasons, evidence, or grounds offered in support | "Research consistently shows that rehabilitative sentences reduce reoffending." |
| Inference | The logical step from premises to conclusion | The implied reasoning: "If rehabilitation reduces reoffending, then we should favour it over punishment." |
| Conclusion | The claim the author wants you to accept | "The criminal justice system should prioritise rehabilitation over punishment." |
| Question Type | How Argument Structure Helps |
|---|---|
| Main conclusion | You must distinguish the conclusion from premises and background statements |
| Assumption | You must identify the unstated premise that connects the stated premises to the conclusion |
| Strengthening / Weakening | You must identify what the argument depends on, so you can see what would support or undermine it |
| Author's purpose | Understanding the argument structure reveals why the author includes each element |
| Inference | You must follow the logical chain from premises through to what necessarily follows |
| Specific detail | Even detail questions are easier when you know whether the detail is a premise, example, or counter-argument |
The simplest argument has this structure:
Premise: "All citizens should have equal access to justice." Premise: "Legal aid cuts have made access to justice dependent on ability to pay." Inference: If equal access requires affordability and legal aid cuts have removed affordability... Conclusion: "Legal aid cuts are unjust and should be reversed."
In practice, LNAT passages present this structure within flowing prose, without labels. Your task is to reconstruct the chain from the text.
Step 1: Find the conclusion. Ask: "What is the author trying to persuade me of?" The conclusion is the destination — everything else is the journey.
Step 2: Find the premises. Ask: "Why does the author believe the conclusion?" The premises are the reasons offered in support.
Step 3: Identify the inference. Ask: "How do the premises lead to the conclusion? What logical step connects them?" This step is often not stated explicitly — it is the inference, and it may rely on an assumption (covered in later lessons).
A simple argument has one or two premises leading directly to a conclusion:
"Compulsory voting increases turnout (premise). Higher turnout produces more representative governments (premise). Therefore, compulsory voting should be adopted (conclusion)."
The structure is linear:
Premise 1 + Premise 2 → Conclusion
Most LNAT passages contain complex arguments with multiple layers:
"Research shows that early intervention reduces youth crime (Premise A). Reduced youth crime leads to lower prison populations (Premise B). Lower prison populations save public money (Premise C). Therefore, early intervention is cost-effective (Sub-conclusion D). Moreover, it produces better outcomes for young people and communities (Premise E). Therefore, the government should invest heavily in early intervention programmes (Main conclusion F)."
The structure has layers:
Premise A + Premise B + Premise C → Sub-conclusion D
Sub-conclusion D + Premise E → Main Conclusion F
Key Insight: The sub-conclusion (D) functions as both a conclusion (supported by A, B, C) and a premise (supporting F). This dual role is what makes complex arguments challenging — and what LNAT questions exploit.
In a published passage, argument components are embedded in natural prose. Here is a realistic passage excerpt with each component labelled:
"The UK's first-past-the-post electoral system regularly produces parliaments that do not reflect the popular vote. [Premise 1] In the 2019 general election, the Conservative Party won 56% of seats with just 43% of the vote, while the Liberal Democrats won 2% of seats with 12% of the vote. [Evidence supporting Premise 1] This disproportionality is not an occasional anomaly; it is a structural feature of the system. [Premise 2] A democracy that systematically misrepresents the will of its citizens cannot claim full legitimacy. [Premise 3 — a value claim] It is therefore time for the UK to adopt a proportional representation system. [Main conclusion]"
As you read, assign each claim one of these labels:
| Label | Question to Ask |
|---|---|
| Conclusion | Is this the point the author wants me to accept? |
| Premise | Is this a reason or piece of evidence supporting the conclusion? |
| Sub-conclusion | Is this supported by evidence AND does it support something bigger? |
| Background | Is this context or scene-setting that is not part of the argument? |
| Counter-argument | Is this a view the author disagrees with? |
| Rebuttal | Is this the author's response to a counter-argument? |
| Example | Is this a specific case illustrating a general claim? |
These two tests are the most reliable tools for identifying conclusions and premises.
Insert "therefore" before a claim. If the passage still makes sense, it may be a conclusion:
"The system regularly produces disproportionate results. The system cannot claim full legitimacy. Therefore, the UK should adopt proportional representation."
This works — "the UK should adopt proportional representation" is the conclusion.
Insert "because" after a claim and check whether the reasons follow naturally:
"The UK should adopt proportional representation because the current system produces disproportionate results and because a democracy that misrepresents its citizens cannot claim legitimacy."
This works — the claim before "because" is the conclusion; the claims after "because" are premises.
These tests are heuristics, not guarantees. They can mislead in two situations:
Not everything in a passage is part of the argument. Learning to distinguish argumentative content from non-argumentative content saves time and prevents errors.
| Type | Description | Example |
|---|---|---|
| Background information | Facts that set the scene but do not support the conclusion | "The UK has used first-past-the-post since the 19th century." |
| Narrative / Anecdote | A story used for illustration, not as evidence | "When I first voted at 18, I assumed my vote would count equally..." |
| Rhetorical flourish | Language designed for effect rather than logical support | "It is a travesty of democracy." |
| Digression | A tangential point that does not advance the argument | "Interestingly, Australia uses a different form of preferential voting..." |
LNAT questions may include answer options that quote non-argumentative content. If a question asks for the main conclusion or a premise, selecting background information or a rhetorical flourish is always wrong.
"The rise of artificial intelligence poses significant challenges to employment. A 2023 report by the OECD estimated that 27% of jobs across member countries are at high risk of automation. While new technologies have historically created more jobs than they destroy, the pace of AI development may outstrip the economy's ability to adapt. Workers in routine cognitive and manual roles are particularly vulnerable.
Some economists argue that the market will self-correct — that displaced workers will retrain and new industries will emerge. This optimism, however, ignores the evidence from recent decades: wage stagnation, rising inequality, and the hollowing out of middle-skill employment suggest that the adjustment process is neither smooth nor equitable.
Governments cannot afford to wait for the market to resolve this. Proactive investment in education, retraining, and social safety nets is essential to ensure that the benefits of AI are widely shared rather than concentrated among a technological elite."
| Passage Element | Component |
|---|---|
| "AI poses significant challenges to employment" | Background / scene-setting |
| "27% of jobs at high risk of automation" | Evidence (supporting the challenge claim) |
| "The pace of AI may outstrip the economy's ability to adapt" | Premise 1 |
| "Workers in routine roles are particularly vulnerable" | Premise 2 |
| "The market will self-correct" | Counter-argument |
| "Wage stagnation, rising inequality, hollowing out of middle-skill employment" | Evidence against the counter-argument |
| "The adjustment process is neither smooth nor equitable" | Sub-conclusion (rebuts the counter-argument) |
| "Governments cannot afford to wait" | Premise 3 (urgency claim) |
| "Proactive investment in education, retraining, and social safety nets is essential" | Main conclusion |
Every LNAT passage presents an argument — a set of premises connected by inferences to a conclusion. Understanding this structure is not one skill among many; it is the foundation for every question type. Use the "therefore" and "because" tests to identify conclusions and premises. Distinguish argument components (premises, conclusions, sub-conclusions) from non-argumentative content (background, anecdote, rhetoric). Recognise the difference between simple and complex arguments, and note that sub-conclusions function as both conclusions and premises. Master this structure, and every subsequent lesson in this course becomes easier.