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The LNAT Section A presents you with approximately 12 argumentative passages, each followed by multiple-choice questions that test your ability to read critically. A significant proportion of these questions — directly or indirectly — require you to recognise flawed reasoning. Understanding logical fallacies is therefore not an academic luxury; it is a practical necessity for achieving a strong LNAT score.
A logical fallacy is an error in reasoning that undermines the logical connection between an argument's premises and its conclusion. The premises may sound persuasive, the language may be eloquent, and the conclusion may even be true — but if the reasoning that connects them is flawed, the argument is fallacious.
| Term | Definition |
|---|---|
| Fallacy | A pattern of reasoning that is logically invalid or misleading |
| Formal fallacy | A flaw in the logical structure of an argument (e.g., affirming the consequent) |
| Informal fallacy | A flaw in the content, context, or presentation of an argument (e.g., ad hominem) |
Key Distinction: Most LNAT passages contain informal fallacies — errors in how evidence is used, how opponents are characterised, or how conclusions are drawn from premises. You do not need to memorise Latin names; you need to recognise the patterns.
LNAT questions rarely ask, "Which fallacy is committed in this passage?" Instead, they test your ability to spot flawed reasoning through questions such as:
Each of these question types requires you to identify what has gone wrong in the reasoning — and that is precisely what fallacy recognition equips you to do.
Consider this short argument:
"Professor Williams has argued that the criminal justice system should focus more on rehabilitation than punishment. But Professor Williams was once arrested for tax evasion. We should therefore reject her views on criminal justice entirely."
A question might ask: "Which of the following is a flaw in the above argument?"
The correct answer would identify that the argument attacks the person rather than addressing her reasoning — a classic ad hominem fallacy. The author's arrest record has no bearing on whether rehabilitation is an effective approach to criminal justice.
Not every weak argument commits a named fallacy. Some arguments are weak because the evidence is thin, the sample size is small, or the conclusion overstates the premises. A fallacy, by contrast, involves a specific, identifiable pattern of flawed reasoning.
| Type | Description | Example |
|---|---|---|
| Weak argument | Evidence is insufficient but reasoning pattern is not inherently flawed | "One study found X, so X must be true everywhere" |
| Fallacious argument | A recognisable error pattern undermines the reasoning | "You cannot trust his argument about taxation — he is a millionaire" (ad hominem) |
LNAT Tip: When evaluating LNAT answer options, look for the option that identifies the most specific and structural flaw. Generic criticisms like "the author has not considered all perspectives" are usually weaker answers than precise identifications of reasoning errors.
Fallacies persist because they feel convincing. Understanding why they are psychologically compelling helps you resist being drawn in during the exam.
Many fallacies exploit emotions rather than logic. An appeal to fear ("If we do not act now, civilisation will collapse") can feel urgent and compelling, even when the causal chain is unfounded.
Fallacies like appeal to popularity ("Everyone agrees that...") or appeal to authority ("The Prime Minister says...") leverage social trust rather than logical evidence.
Our brains are wired to take shortcuts. When someone provides a vivid anecdote, we instinctively treat it as representative — even though a single example proves nothing about general patterns.
LNAT Relevance: The passages in Section A are written to be persuasive. They are drawn from opinion columns, academic essays, and policy debates — genres where fallacious reasoning is common precisely because it is effective at persuading readers. Your job is to see through the persuasion and evaluate the logic.
When reading any LNAT passage, apply this systematic approach:
| Category | What goes wrong | Covered in lesson |
|---|---|---|
| Attacking the person | The argument targets the speaker, not the claim | 2 |
| Misrepresenting arguments | The argument distorts or ignores the real issue | 3 |
| False choices | The argument presents fewer options than actually exist | 4 |
| Unfounded predictions | The argument assumes unjustified chain reactions | 5 |
| Circular reasoning | The argument assumes what it is trying to prove | 6 |
| Misuse of authority/popularity | The argument appeals to status rather than evidence | 7 |
| Overgeneralisation | The argument draws broad conclusions from limited data | 8 |
| Language exploitation | The argument shifts meanings or exploits vagueness | 9 |
Over the next nine lessons, you will study each major category of fallacy in depth, with:
By the end of this course, you will be able to recognise fallacious reasoning quickly and reliably — a skill that will directly improve your performance on LNAT Section A.
Logical fallacies are patterns of flawed reasoning that undermine the connection between premises and conclusion. The LNAT tests your ability to spot these flaws through questions about argument weaknesses, vulnerabilities, and logical gaps. Fallacies are persuasive because they exploit emotions, social pressure, and cognitive shortcuts — which is why deliberate, systematic analysis is essential. This course will equip you with the specific fallacy-recognition skills you need for a strong LNAT Section A performance.