Logical Reasoning: Argument Structure and Evidence
What Logical Reasoning tests
CLAT logical reasoning is largely critical reasoning: identify the conclusion, assumption, strengthening or weakening evidence, inference, flaw, and method of argument. It tests structure, not whether you agree with the conclusion.
Core rules
- Label premises and conclusion. The conclusion is what the argument wants you to accept.
- An assumption is unstated but necessary; negate it and see whether the argument collapses.
- Strengthen and weaken choices must affect the link between evidence and conclusion.
- Correlation is not causation; look for alternative causes, reverse causation, and biased samples.
- For inference, accept only what must follow, not what could follow.
Worked example
Argument: "After the city banned plastic bags, street litter fell by 20% in one year. Therefore, the ban caused the reduction." Question: Which fact most weakens the argument? A. The ban was popular. B. A separate cleanup drive began the same year. C. Some shoppers disliked the ban. D. Plastic bags are cheap. Reasoning: The conclusion is causal. B supplies an alternative cause for the same drop, so the ban is no longer the only explanation. A and C concern opinion; D is irrelevant to the causal link.
Traps
Reject choices that merely restate a premise. Do not attack the speaker instead of the reasoning. For assumption questions, a sufficient condition is not always necessary. For "except" questions, track the polarity. An out-of-scope comparison cannot strengthen or weaken the argument.