Drawing Valid Inferences from Passages

The previous lesson introduced what inferences are. This lesson focuses on the practical skill of drawing valid inferences from longer, more complex passages — the kind you will encounter on the LNAT. You will learn a systematic method for determining what logically follows from a passage and, crucially, what does not.

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The Golden Rule of Inference

An inference must be supported by the passage. If you need information from outside the passage to justify the inference, it is not valid.

This rule sounds simple, but it is remarkably difficult to apply under time pressure. Your brain naturally fills in gaps using your existing knowledge and beliefs. On the LNAT, you must consciously resist this tendency.

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Types of Information in a Passage

When reading an LNAT passage, recognise that it contains different types of information:

Type	Description	Can you infer from it?
Explicit statements	Directly stated facts or claims	Yes — but the inference must go beyond mere restatement
Implicit information	Not stated directly but logically implied by what is stated	Yes — this is the core of inference questions
Tone and emphasis	The author's attitude, conveyed through word choice and structure	Sometimes — if the tone clearly implies something
Absence of information	What the passage does NOT say	Rarely — you generally cannot infer from silence

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Method: The Three-Step Inference Test

For each potential inference, apply these three steps:

Step 1: Identify the Relevant Evidence

Which specific statements in the passage relate to the proposed inference?

Step 2: Check the Logical Connection

Does the evidence actually support the inference? Is the connection strong (must be true or very likely true) or weak (merely possible)?

Step 3: Check for Over-Interpretation

Are you adding anything that is not in the passage? Are you making assumptions based on general knowledge rather than the text?

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Worked Example 1: A Straightforward Passage

Passage:

"The council's decision to close the community swimming pool has been met with widespread local opposition. A petition with over 3,000 signatures was submitted within a week, and two protest marches have taken place. The council argues that the pool operates at a significant financial loss and that the funds could be better spent on services that benefit a larger number of residents."

Proposed inferences:

Inference	Valid?	Reasoning
The community swimming pool is currently open	Valid	The passage discusses the decision to "close" it — it cannot be closed if it is not currently open
At least 3,000 people live in the local area	Valid	Over 3,000 people signed the petition. They must exist, so the local population is at least 3,000
The council will reverse its decision	Invalid	The opposition is described, but nothing suggests the council will change course
Fewer people use the swimming pool than use other council services	Valid (implied)	The council says funds could be "better spent on services that benefit a larger number of residents", implying the pool benefits fewer people
The council does not care about local residents' views	Invalid	The passage describes opposition but does not indicate the council is dismissing it. The council has provided a reason for its decision

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Worked Example 2: A More Complex Passage

Passage:

"Proponents of autonomous vehicles frequently cite safety as the primary benefit. Human error is responsible for approximately 94% of road traffic accidents, and computers do not get tired, distracted, or drunk. However, this argument overlooks the fact that autonomous vehicle technology is still in development, and current systems struggle with unpredictable situations — a child running into the road, unusual road layouts, or adverse weather conditions. Furthermore, widespread adoption of autonomous vehicles would require a complete overhaul of road infrastructure and liability law, at enormous cost. The safety benefits, while real in principle, are far from guaranteed in practice."

Question: Which of the following can be inferred from the passage?