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Double-Crux

Double-Crux is a structured dialogue technique designed to help people with opposing views find productive common ground by identifying the key beliefs that, if changed, would alter their overall position on a topic.

Core Concept

The technique is based on finding "cruxes" - specific beliefs or pieces of evidence that are central to someone's position. A crux is something where:

  • If you became convinced it was false, you would significantly change your mind about the overall topic

  • It's a load-bearing belief that supports your broader conclusion

A double-crux occurs when both parties identify a shared sub-question where:

  • Person A thinks X is true, and this belief is a crux for their position

  • Person B thinks X is false, and this belief is a crux for their opposing position

  • Both agree that resolving question X would significantly change their minds

The Process

1. Identify Individual Cruxes

Each person asks themselves: "What would need to be true or false for me to change my mind about this topic?"

2. Share and Compare Cruxes

Participants share their cruxes and look for overlaps - areas where they disagree about the same underlying question.

3. Focus on the Double-Crux

Instead of debating the original broad topic, focus intensively on the shared crux that both find decisive.

4. Investigate Together

Collaboratively explore the evidence and reasoning around the double-crux question.

Example Scenario

Topic: Should we increase funding for public schools?

Person A's crux: "If I believed that additional funding doesn't improve educational outcomes, I would change my mind about increasing school funding."

Person B's crux: "If I believed that additional funding significantly improves educational outcomes, I would support increasing school funding."

Double-crux identified: "Does additional funding improve educational outcomes?"

Now both can focus on examining evidence about funding and educational outcomes rather than debating the broader policy question.

Benefits

More Productive Disagreement

  • Moves from position-based arguing to collaborative truth-seeking

  • Reduces defensive responses and emotional escalation

  • Focuses discussion on resolvable empirical questions

Deeper Understanding

  • Forces people to examine their own reasoning chains

  • Identifies which beliefs are actually central vs. peripheral

  • Reveals hidden assumptions and unstated premises

Relationship Preservation

  • Maintains respect and good faith between disagreeing parties

  • Creates shared goals (understanding the truth about the crux)

  • Reduces the social cost of changing one's mind

Challenges and Limitations

Difficulty Finding True Cruxes

  • People often think they know what would change their minds but may be wrong

  • Some beliefs are more entrenched than people realize

  • Social and emotional factors may outweigh logical considerations

Asymmetric Cruxes

  • Sometimes cruxes don't line up cleanly between participants

  • One person's crux may not be relevant to the other's reasoning

  • Different people may have entirely different foundational assumptions

Implementation Challenges

  • Requires significant skill and practice to facilitate well

  • Participants need to be genuinely open to changing their minds

  • Can be time-consuming and emotionally demanding

Skills and Prerequisites

For Participants

  • Intellectual humility: Genuine openness to being wrong

  • Self-awareness: Understanding your own reasoning process

  • Good faith: Honest engagement rather than trying to "win"

  • Curiosity: Interest in understanding rather than just persuading

For Facilitators

  • Active listening: Understanding each person's actual position

  • Question-asking: Helping people dig deeper into their reasoning

  • Neutrality: Not taking sides or pushing toward particular conclusions

  • Process management: Keeping focus on the method rather than content

Applications

Personal Relationships

  • Resolving ongoing disagreements between friends or family

  • Working through relationship conflicts

  • Parenting decisions between partners

Professional Settings

  • Strategic business decisions with multiple stakeholders

  • Research collaborations with methodological disagreements

  • Policy discussions in organizations

Public Discourse

  • Political discussions between people with different ideologies

  • Community decision-making processes

  • Academic or intellectual debates

Steel-manning

  • Presenting the strongest version of the opposing argument

  • Complementary to double-crux by ensuring fair representation of views

Collaborative Truth-Seeking

  • Broader category of methods that emphasize finding truth over winning arguments

  • Includes techniques like Socratic questioning and structured debate

Active Listening

  • Foundation skill for understanding others' actual positions

  • Essential for identifying genuine cruxes rather than strawmen

Origins and Development

Double-crux was developed and popularized by the Center for Applied Rationality (CFAR) as part of their rationality training curriculum. It draws from:

  • Cognitive science research on belief updating

  • Conflict resolution and mediation techniques

  • Philosophical traditions of collaborative inquiry

The technique continues to evolve through practical application in workshops, online discussions, and research into effective communication methods.

Key Takeaways

Double-crux is most powerful when both parties genuinely want to understand the truth rather than win an argument. It works best on questions that have factual answers rather than pure value differences, though it can help clarify value disagreements by separating them from factual disputes.

The technique recognizes that most complex disagreements involve multiple layers of reasoning, and that finding shared points of inquiry can be more productive than debating conclusions directly.