Critical Thinking Cheat Sheet: Lesson 1 - Recognising Assumptions
What Are Assumptions?
- Unexamined beliefs accepted as true without evidence
- The invisible foundations of our thinking
- Can be factual, value-based, prescriptive, or causal
- Necessary for thinking but problematic when unrecognized
Types of Assumptions
Type | Description | Example |
Factual | Beliefs about what is true | “Crime is increasing in my city” |
Value | Beliefs about what matters | “Freedom is more important than security” |
Prescriptive | Beliefs about what should be done | “The government should regulate this industry” |
Causal | Beliefs about what causes what | “Violent video games lead to aggressive behavior” |
Spotting Assumptions: Key Techniques
- Look for gap words: “obviously,” “clearly,” “naturally,” “of course”
- Work backwards: Identify conclusion, then ask what must be true for it to make sense
- Consider the opposite: What if the contrary were true?
- Five Whys technique: Ask “why” repeatedly to uncover deeper assumptions
- Notice emotional reactions: Strong emotions often signal challenged assumptions
Reasonable vs. Unreasonable Assumptions
Reasonable assumptions: - Based on reliable evidence or consistent experience - Acknowledged as assumptions rather than certainties - Open to revision when new information emerges - Necessary for practical functioning
Unreasonable assumptions: - Based on limited, biased, or outdated information - Treated as unquestionable facts - Resistant to revision despite contradictory evidence - More extreme or absolute than warranted
Managing Your Assumptions
- Keep an assumption journal for important decisions
- Seek diverse perspectives to challenge your default assumptions
- Practice intellectual humility
- Distinguish between observations (what you perceive) and interpretations (meaning you assign)
- Remember: Good critical thinkers don’t eliminate assumptions but recognize and evaluate them