Mastering Assumptions in Syllogisms and Critical Reasoning
In competitive exams like the CAT, understanding how to identify assumptions is a crucial skill for dissecting arguments and arriving at correct conclusions. An assumption is an unstated premise that must be true for the argument's conclusion to logically follow from its stated premises.
What is an Assumption?
An assumption bridges the gap between the evidence presented and the conclusion drawn. It's the hidden belief or fact that the arguer takes for granted. Without this unstated belief, the argument would fall apart.
Assumptions are unstated premises essential for an argument's validity.
Think of an argument like a chain. The stated premises are the visible links, and the conclusion is the end. An assumption is the hidden link that connects the last visible premise to the conclusion.
In logical reasoning, an argument consists of premises (statements offered as evidence) and a conclusion (the statement that the premises are intended to support). An assumption is a statement that is not explicitly stated but is necessary for the conclusion to be logically derived from the premises. If the assumption is false, the argument is weakened or invalidated.
How to Identify Assumptions
A common technique to identify assumptions is the 'negation test'. If you negate an assumption and the argument's conclusion no longer follows, then the original statement was indeed an assumption.
To provide an unstated link that makes the conclusion logically follow from the stated premises.
Let's consider an example: 'This new marketing campaign is excellent because it uses vibrant colors and catchy slogans.' The stated premises are 'vibrant colors' and 'catchy slogans'. The conclusion is 'excellent marketing campaign'. What's the assumption?
The unstated assumption here is that vibrant colors and catchy slogans are sufficient indicators of an excellent marketing campaign.
Applying the negation test: If we negate the assumption ('Vibrant colors and catchy slogans are NOT sufficient indicators of an excellent marketing campaign'), the conclusion ('This new marketing campaign is excellent') no longer necessarily follows from the premises. This confirms our identified assumption.
Types of Assumptions
| Type of Assumption | Description | Example Scenario |
|---|---|---|
| Necessary Assumption | Must be true for the argument to hold. | Argument: 'The company's profits increased last quarter, so its new strategy must be working.' Assumption: The new strategy is the primary reason for the profit increase. |
| Supporter Assumption | Provides additional support or justification for the argument. | Argument: 'We should invest in renewable energy to combat climate change.' Assumption: Renewable energy is an effective way to combat climate change. |
In many exam questions, you'll be asked to identify the assumption that most weakens or most strengthens the argument. This requires understanding how different unstated premises impact the argument's validity.
Common Pitfalls to Avoid
Be careful not to confuse assumptions with the stated premises or the conclusion itself. Also, avoid assumptions that are too broad or too narrow. The correct assumption is the one that is necessary for the argument to make sense.
To verify if a statement is a necessary assumption by negating it and checking if the argument's conclusion still holds.
Practice Makes Perfect
Regularly practicing syllogisms and critical reasoning questions, specifically focusing on identifying assumptions, will build your intuition and accuracy. Pay close attention to the wording and the logical connections between statements.
Learning Resources
This blog post from PowerScore, a renowned test prep company, provides a clear explanation of assumptions in critical reasoning and how to identify them.
A concise explanation of assumptions and how they function within logical arguments, offering a foundational understanding.
A video tutorial that breaks down the concept of assumptions in logical reasoning, often applicable to competitive exam formats.
This article offers practical strategies and examples for identifying the underlying assumptions in various types of arguments.
Manhattan Prep's blog post delves into the nuances of assumptions, including common traps and effective techniques for tackling them.
This article specifically focuses on the powerful negation test method for identifying necessary assumptions in GMAT-style questions.
A comprehensive guide on GMAT Club discussing assumptions, including different types and practice strategies.
This resource focuses on assumptions within the context of syllogisms, providing examples and explanations relevant to Indian competitive exams.
Kaplan Test Prep offers insights into identifying assumptions, covering common question types and strategies for success.
While not solely about assumptions, this article from The Economist provides a broader context for identifying flawed arguments, which often involves unearthing hidden assumptions.