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“Don’t make assumptions.” The third agreement from Don Miguel Ruiz’s The Four Agreements is simple yet transformative. We’ve all heard the old cliché that the word “assume” makes an “ass” out of “u” and “me.” Ruiz takes this idea and applies a spiritual and psychological lens to it.
Making assumptions is dangerous because we often have no idea what’s actually happening in a given situation. We fill in the gaps in our knowledge with imagination, convince ourselves our “truth” is reality, and then act on those mistakes—leading to unnecessary suffering. Read on to learn why we make assumptions and how to master the third agreement.
Originally Published: June 18, 2019
Last Updated: December 31, 2025
Why We Make Assumptions (And Why It’s Dangerous)
Making assumptions comes naturally to us. We are often impressed by our own “insight,” but Ruiz warns that this is often the Mitote—the chaos of the mind—at work. He offers the third agreement (“Don’t make assumptions”), warning that assumptions follow a predictable, destructive cycle:
- The assumption: We create a story to fill an information gap.
- The misunderstanding: We misinterpret someone’s words or actions.
- Taking it personally: We get offended (linking to the second agreement).
- Reaction: We lash back or gossip to defend ourselves.
- Drama: A small spark turns into a forest fire of conflict.
The “Universal Perspective” Fallacy
The biggest assumption we make is thinking everyone sees life exactly as we do. We assume others judge, think, and feel the way we do. In reality, everyone perceives the world through a unique lens. Without clear communication, these different “realities” are bound to collide.
Assumptions in Relationships and Daily Life
Assumptions act as blinders, especially in our closest relationships. We often see what we want to see rather than what is actually there.
- The Romantic Fantasy: Imagine you’re at the mall and someone you like smiles at you from a distance. You might assume they’re deeply in love with you, creating a fantasy that has no basis in reality. This sets you up for heartache or embarrassment.
- The “Mind Reader” Trap: We often assume our partners know what we’re thinking. We might enter a relationship thinking, “My love will change her.” But real love accepts people as they are. When we don’t communicate our expectations (such as views on monogamy or time spent together), anger and resentment take root.
- The Digital Misinterpretation: In the modern world, this happens via text. If a friend sends a “curt” message, you might assume they’re mad at you and preemptively distance yourself. In reality, they might just be busy, and your assumption creates a rift where there was none.
Assumptions About Yourself
The danger isn’t just external; we make assumptions about our own limits. We either underestimate ourselves (leading to self-doubt) or overestimate our current capacity (leading to recriminations), rather than seeking the truth of our potential.
How to Stop Making Assumptions: The Power of Clarity
The antidote to assumptions is communication and clarification. If you have the courage to ask questions, you can seek the truth. When you know the truth, you no longer have a “need” to assume.
(Shortform note: Be comfortable asking questions you’re afraid might be too simple or dumb, such as “Why do you feel that way?” “What motivated you to do that?” or “What would you do in my situation?” If you ask these in the right tone, these are fantastic questions to get rid of assumptions on both sides.)
Example: You see a coworker go to lunch with the boss and assume they got the promotion you wanted. Instead of stewing in anxiety, ask for a meeting. Find out the status of the promotion and what you need to do to reach your goals. Focus on facts, not signals.
(Shortform note: While Ruiz focuses on stopping the habit of assuming, other experts suggest a shift in mindset. In Difficult Conversations, Douglas Stone, Bruce Patton, and Sheila Heen make a similar point that we should replace certainty with curiosity. However, they also add a few nuances to Ruiz’s advice: First, they say to acknowledge that both perspectives are valid. Your feelings might be hurt, even if your assumption about another person was wrong. Second, you should avoid negative assumptions, but they recommend assuming the other person has positive intentions. And, lastly, if someone accuses you of having bad intentions, avoid being reflexively defensive and question yourself to examine your true intentions. They argue that these steps will help you start difficult conversations on the right foot.)
Steps to Master the Third Agreement
- Awareness: You cannot change a habit you don’t notice. Catch yourself when you start “filling in the blanks.”
- Ask questions: Have the courage to seek clarity. Facts are the enemy of assumptions.
- Communicate openly: Don’t expect others to be mind-readers. Be clear about what you want and how you feel.
- Assume positive intent: When in doubt, lean toward curiosity rather than judgment.
- Take action: Forge a new habit through repetition. Every time you choose truth over a “guess,” you strengthen this agreement.
When you make the third agreement and stop making assumptions, the blinders fall away. You begin to understand your life as it truly is, leading to a foundation of honesty and peace.
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