Argument Analysis
Topic overview
Argument analysis tests your ability to evaluate the strength of arguments: identifying premises and assumptions, judging what would weaken or strengthen a conclusion, and pointing out flaws in reasoning. This is the part closest to the LNAT and to legal thinking — a lawyer's core work is precisely dissecting arguments.
Key concepts
Premises are the reasons given, the conclusion is the claim being supported, and an assumption is a premise that is necessary for the argument to hold but is not stated.
How to find assumptions: ask "for the premises to genuinely support the conclusion, what must also be tacitly assumed in between?" If negating an option makes the argument collapse, it is a key assumption.
Key points
- ◆An assumption is an "implicit and necessary" bridge
- ◆Negate the assumption → the argument collapses (negation test)
- ◆Don't choose something the passage already states explicitly — that is a premise, not an assumption
Weaken: find an option that, if true, would shake the conclusion or sever the bridge from premises to conclusion. Strengthen: conversely, supply the missing link or provide supporting evidence.
The strongest weakening usually attacks the core assumption directly or provides reverse causation/a counterexample; irrelevant, minor options do not count.
Key points
- ◆Weakening/strengthening targets the "conclusion", not just any random sentence
- ◆Experimental control (changing one variable and observing the result) is strong causal evidence
- ◆Subjective, marginal information such as 'some people dislike' is usually irrelevant
- Correlation ≠ causation: two things occurring together does not mean one causes the other (it could be the reverse, or there could be a third factor).
- Slippery slope: assuming that allowing one case necessarily slides into a chain of extreme consequences.
- Either/or (false dilemma): reducing a continuum/multiple options to just two extremes.
- Ad hominem: attacking the person making the argument rather than the argument itself.
- Circular reasoning: using the conclusion itself as the reason.
- Hasty generalisation: generalising from a small sample to the whole.
Key points
- ◆Seeing "A and B occur together, therefore A causes B" → think correlation vs causation
- ◆"Once... then it will inevitably go all the way to..." → slippery slope
- ◆Inferring "all cities should do it" from "it works in some cities" → overgeneralisation
Quickly 'draw the skeleton' of the passage: which sentence is the claim, which are the reasons, where is the concession, where is the rebuttal. Common structures:
- Claim + reasons, followed by counter-evidence (introduced by 'But / Yet').
- Concession ('There is something to this') + qualifying challenge.
- Definition + example.
Once the structure is clear, the questions often answer themselves.
Key points
- ◆'But / Yet / However' are the watersheds of structure
- ◆A concession is not agreement — it often sets up a rebuttal
- ◆Mark the conclusion first, then look at the role each sentence plays relative to it
Worked examples
Try each example yourself before checking the explanation.
Argument: 'Free evening classes will reduce crime, because learners will have no time to commit crimes.' What is the implicit assumption?
'The teenagers who use social media most are also the most anxious, so social media causes anxiety.' Where is the flaw?
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