Cause and Effect Reasoning

Many LNAT passages make claims about what causes what. "X leads to Y", "Y is the result of Z", "A is responsible for B". Causal reasoning is fundamental to argumentative writing — and it is also where many arguments go wrong. The LNAT frequently tests your ability to evaluate causal claims and identify errors in causal reasoning.

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Correlation vs Causation

The single most important principle in evaluating causal reasoning is:

Correlation does not prove causation.

Two things occurring together (correlation) does not mean that one causes the other. This is the most commonly tested causal reasoning concept on the LNAT.

Example

"Countries with higher chocolate consumption have more Nobel Prize winners per capita."

This is a real statistical correlation. But it would be absurd to conclude that eating chocolate causes Nobel Prizes. Both variables may be correlated with a third factor — national wealth, which funds both luxury food consumption and research institutions.

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Four Errors in Causal Reasoning

1. Post Hoc Fallacy (Post Hoc Ergo Propter Hoc)

"After this, therefore because of this."

Just because event B occurred after event A does not mean A caused B.