Assumption Inference

Assumption Inference problems require identifying the hidden assumptions or unstated premises that must be true for an argument to be logically valid. You must recognize what the argument takes for granted, what must be assumed for the conclusion to follow from the evidence.

10Worksheets
200+Practice Questions
HardDifficulty
3-4 hoursHours to Master

Introduction to Assumption Inference

Assumption Inference problems require identifying the hidden assumptions or unstated premises that must be true for an argument to be logically valid. You must recognize what the argument takes for granted, what must be assumed for the conclusion to follow from the evidence.

Prerequisites

Understanding of argument structure Premise and conclusion identification Logical gaps recognition Necessary condition concept
Why This Matters: Assumption Inference problems appear in 1-2 questions in CAT, GMAT, and Banking PO exams. They test critical analysis of arguments.

How to Solve Assumption Inference Problems

1

Step 1: Identify the conclusion and the evidence/premises

2

Step 2: Identify the logical gap between premises and conclusion

3

Step 3: Determine what unstated premise would bridge this gap

4

Step 4: Test the assumption using the negation test

5

Step 5: If negating the assumption destroys the argument, it is a necessary assumption

6

Step 6: Ensure the assumption is not already stated

7

Step 7: Select the assumption that must be true for the argument to hold

Pro Strategy: Use the negation test: If negating a candidate assumption makes the argument invalid, that assumption is necessary. Look for what the argument takes for granted without explicitly stating.

Example Problem

Example: John got promoted quickly. He must have worked very hard. What is the hidden assumption? Solution: Step 1: Premise: John got promoted quickly Step 2: Conclusion: John worked very hard Step 3: Gap: Hard work is necessary for quick promotion Step 4: Assumption: Quick promotion is achieved only through hard work Step 5: Negation test: If quick promotion can happen without hard work (e.g., luck, connections), the argument fails Answer: Hard work is the only way to get promoted quickly

Pro Tips & Tricks

  • Assumptions bridge the gap between evidence and conclusion
  • Necessary assumptions must be true for the argument to be valid
  • The negation test: If ¬A makes argument invalid, A is a necessary assumption
  • Assumptions are often about causal relationships or value judgments
  • Avoid assumptions that are already stated in the premises
  • Look for unstated generalizations or universal claims

Shortcut Methods to Solve Faster

If argument uses 'must have', assumption is about necessity
If argument uses 'therefore', assumption connects premise to conclusion
Statistical arguments assume sample represents population
Causal arguments assume no confounding variables
Comparative arguments assume relevant similarities

Common Mistakes to Avoid

Confusing stated premises with hidden assumptions
Choosing assumptions that are not necessary for the argument
Failing to apply the negation test
Identifying conclusions as assumptions

Exam Importance

Assumption Inference is an important topic for various competitive exams. Here's how frequently it appears:

SSC CGL
1-2 questions
BANKING PO
1-2 questions
RAILWAYS RRB
1-2 questions
CAT
2-3 questions
GMAT
2-3 questions
INSURANCE
1-2 questions

Ready to Master Assumption Inference?

Start with Worksheet 1 and work your way up to expert level! Each worksheet includes:

20 practice questions
Detailed solutions
Step-by-step explanations
Start Practicing Now