In-Depth: Assumptions

CLAT Application & Relevance

Importance: VERY HIGH. Identifying unstated assumptions is a core skill tested repeatedly in CLAT Logical Reasoning. Assumptions are the unstated bridges that connect an argument's premises to its conclusion. If an assumption is not true, the argument falls apart. Recognizing these underlying beliefs is crucial for evaluating the validity of arguments, a skill directly applicable to legal reasoning.

How it's tested: Questions like "Which of the following is an assumption on which the argument depends?", "The conclusion above relies on which of the following unstated premises?", "The argument presupposes that...", "Which of the following must be true for the conclusion to follow?"

Section 1: Core Concepts & Identification Strategies

An assumption is an unstated premise that is absolutely necessary for an argument's conclusion to logically follow from its stated premises. It's something the author takes for granted as true when making their argument.

Key Characteristics of an Assumption:

Unstated: It is not explicitly written in the argument.
Necessary: If the assumption is false, the conclusion cannot be true, or the argument becomes illogical.
Bridge: It often connects new information in the conclusion to the premises, or it eliminates a potential weakness in the argument.

Distinction from Other Concepts:

Assumption ≠ Premise: Premises are stated. Assumptions are unstated.
Assumption ≠ Inference: An inference is a conclusion that *must* be true if the premises are true. An assumption is a premise that *must* be true for the conclusion to logically follow. (The Negation Test helps differentiate).
Assumption ≠ Supporting Evidence: A supporting piece of evidence (if true) strengthens an argument but isn't necessarily *required* for the argument to exist. An assumption is indispensable.

The Negation Test (Crucial Strategy):

This is the most reliable method to verify an assumption.

Identify a potential assumption (often from the answer choices).
Mentally negate it (make it false or its opposite).
If negating the statement destroys or significantly weakens the argument's conclusion, then the original statement *is* a necessary assumption.
If negating the statement has no effect on the argument's conclusion, then it is NOT a necessary assumption.

Common Types of Assumptions:

No Alternative Cause: Assumes that the stated cause is the *only* cause or the *primary* cause.
Future Resembles Past: Assumes that conditions or trends from the past will continue into the future.
Terms Used Consistently: Assumes that a key term or concept means the same thing throughout the argument.
Sufficiency of Evidence: Assumes that the presented evidence is enough to draw the conclusion.
Representativeness: Assumes a sample (e.g., in a survey/study) is representative of the larger population.

Section 2: Solved CLAT-Style Examples

Example 1: Identifying Assumption (No Alternative Cause)

Passage: "To reduce the number of traffic accidents in the city, the Municipal Corporation installed new, brighter streetlights on all major roads last month. Since then, the number of traffic accidents has decreased by 15%. Therefore, the new streetlights are responsible for the reduction in accidents."

Question: "Which of the following is an assumption on which the argument above depends?"

The Municipal Corporation had sufficient budget for the streetlight project.
The drivers in the city are generally more careful at night.
No other significant traffic safety measures were implemented last month.
The total volume of traffic on major roads remained constant.
The 15% reduction in accidents is considered a statistically significant improvement.

Detailed Solution:
1. Identify Argument: Premise: New streetlights installed. Accidents decreased by 15%. Conclusion: New streetlights caused the reduction.
2. Apply Negation Test:
a) Negate: Budget was insufficient. Does not affect whether the streetlights *caused* the reduction, only the practicality. (Not assumption)
b) Negate: Drivers are *not* more careful. Doesn't directly attack the streetlights' role. (Not assumption)
c) Negate: *Other* significant traffic safety measures *were* implemented. If so, then those other measures might be responsible for the decrease, not the streetlights, thus destroying the argument's causal link. This is a necessary assumption (no alternative cause).
d) Negate: Total traffic *did not* remain constant (e.g., it decreased). If traffic decreased, that could be an alternative cause for fewer accidents, weakening the streetlight argument. This is also a strong assumption. In CLAT, if both (c) and (d) are options, (c) is often preferred if the intervention is clear. (d) implies constant conditions. Both are common assumptions. For this example, let's proceed with (c) as the most direct "no other action" type assumption.
e) Negate: The 15% reduction is *not* statistically significant. This weakens the *strength* of the conclusion, but not the causal link itself. (Not assumption)
Answer: Option (c). (Option d is also a very strong implicit assumption for such arguments, as is "the accident reporting system remained consistent").

Example 2: Identifying Assumption (Future Resembles Past / Representativeness)

Passage: "A recent survey of 500 law students at National Law University, Delhi, revealed that 85% plan to pursue corporate litigation after graduation. Therefore, it is highly probable that the majority of all law graduates from Indian National Law Universities this year will pursue corporate litigation."

Question: "The argument's conclusion depends on which of the following assumptions?"

Corporate litigation is the most lucrative field for law graduates.
The survey accurately reflects the career plans of all NLU Delhi law students.
The career plans of NLU Delhi law students are representative of all Indian National Law University graduates.
The total number of law graduates from all Indian NLUs this year will be similar to last year.
Students who plan to pursue corporate litigation will definitely succeed in doing so.

Detailed Solution:
1. Identify Argument: Premise: 85% of 500 NLU Delhi students plan corporate litigation. Conclusion: Majority of ALL Indian NLU graduates this year will pursue corporate litigation.
2. Look for the Gap: The jump is from "500 students at NLU Delhi" (a specific sample) to "all Indian National Law University graduates" (a much larger, broader population).
3. Apply Negation Test:
a) Negate: Corporate litigation is *not* lucrative. Doesn't break the conclusion about *plans*. (Not assumption)
b) Negate: The survey *does not* accurately reflect NLU Delhi students. If the premise itself is flawed, the argument is immediately broken. This is an assumption but it is an assumption about the *premise's accuracy*. The argument's major logical leap is from *one NLU* to *all NLUs*.
c) Negate: The career plans of NLU Delhi law students are *not* representative of all Indian NLU graduates. If this is false, then drawing a conclusion about "all Indian NLU graduates" based *only* on NLU Delhi becomes illogical. This is the crucial bridge assumption for generalization.
d) Negate: Total number of graduates will *not* be similar. Doesn't break the *percentage* or *majority* claim, just the overall scale. (Not assumption)
e) Negate: Students who plan to pursue corporate litigation will definitely succeed in doing so. Doesn't break the conclusion about their *plans*. (Not assumption)
Answer: Option (c). This is the assumption of representativeness, which bridges the gap between the specific sample (NLU Delhi) and the broad conclusion (all Indian NLUs). While (b) is also an assumption about the data, (c) is the one that validates the generalization from the specific sample to the broader population in the conclusion.