The Basic Double Crux pattern

I’ve spent a lot of time developing tools and frameworks for bridging “intractable” disagreements. I’m also the person affiliated with CFAR who has taught Double Crux the most, and done the most work with it.

People often express to me something to the effect,

The important thing about Double Crux is all the low level habits of mind: being curious, being open to changing your mind, paraphrasing to check that you’ve understood, operationalizing, etc. The ‘Double Crux’ framework, itself is not very important.

I half agree with that sentiment. I do think that the low level cognitive and conversational patterns are the most important thing, and at Double Crux trainings that I have run, most of the time is spent focusing on specific exercises to instill those low level TAPs.

However, I don’t think that the only value of the Double Crux schema is in training those low level habits. Double cruxes are extremely powerful machines that allow one to identify, if not the most efficient conversational path, then at least a very high-efficiency conversational path. Effectively navigating down a chain of Double Cruxes, resolving a disagreement at the bottom of the chain, iterating back to the top, and finding that you’ve actually changed you mind, is like magic. So I’m sad when people write it off as useless.

This post represents my current best attempt to encapsulate the minimum viable Double Crux (TM) skill: a basic conversational pattern for steering toward and finding double cruxes. I’m going to try and outline the basic Double Crux pattern, the series of 4 moves that makes Double Crux work, and give a (simple, silly) example of that pattern in action.

Again, this is only a basic schema. These four moves are not (always) sufficient for making a Double Crux conversation work. That does depend on a number of other mental habits and TAPs. And real conversations can throw up all kinds of problems that require more specific techniques and strategies. But this pattern is, according to me, at the core of the Double Crux formalism.

The pattern

For simplicity, I have described this in the form of a 3-person Double Crux conversation, with two participants and a facilitator. Of course, one can execute these same moves in a 2 person conversation, as one of the participants. But that additional complexity is hard to manage for beginners, so I usually have people practice in a facilitation role, to factor out the difficulty of steering the conversation from the difficulty of introspecting on one’s own mental content.

The pattern has two parts, finding a crux, and finding a double crux, and each part is composed of 2 main facilitation moves.

All together, those four moves are…

  1. Clarifying that you understood the first person’s point.

  2. Checking if that point is a crux

  3. Checking the second person’s belief about the truth value of the first person’s crux.

  4. Checking the if the first person’s crux is also a crux for the second person.

In practice

The conversational flow of these moves looks something like this:


This is an intentionally silly, over-the-top-example, for demonstrating the the pattern without any unnecessary complexity.

Two people, Alex and Barbra, disagree about tea: Alex thinks that tea is great, and drinks it all the time, and thinks that more people should drink tea, and Barbra thinks that tea is bad, and no one should drink tea.

Facilitator: So, Barbra, why do you think tea is bad?

Barbra: Well it’s really quite simple. You see, tea causes cancer.

Facilitator: Let me check if I’ve got that: you think that tea causes cancer?

Barbra: That’s right.

Facilitator: Wow. Ok. Well if you found out that tea actually didn’t cause cancer, would you be fine with people drinking tea?

Barbra: Yeah. Really the main thing that I’m concerned with is the cancer-causing. If tea didn’t cause cancer, then it seems like tea would be fine.

Facilitator: Cool. Well it sounds like this is a crux for you Barb. Alex, do you currently think that tea causes cancer?

Alex: No. That sounds like crazy-talk to me.

Facilitator: Ok. But aside from how realistic it seems right now, if you found out that tea actually does cause cancer, would you change your mind about people drinking tea?

Alex: Well, to be honest, I’ve always been opposed to cancer, so yeah, if I found out that tea causes cancer, then I would think that people shouldn’t drink tea.

Facilitator: Well, it sounds like we have a double crux!

[They high five, write down their double crux, and then recurse, seeking a double crux on the claim “tea cause cancer.”]

Caveats and complications

Obviously, in actual conversation, there is a lot more complexity than this example, and a lot of other things that are going on.

For one thing, I’ve only outlined the best case pattern, where the participants give exactly the most convenient answer for moving the conversation forward (yes, yes, no, yes). In actual practice, it is quite likely that one of those answers will be reversed. If a participant gives an “inconvenient answer”, the facilitator has to effectively respond in light of that.

For another thing, this formalism is rarely so simple. You might have to do a lot of conversational work to clarify the claims enough that you can ask if B is a crux for A.

In particular, in a real conversation, the first step (checking whether you’ve understood), usually requires a fair amount of distillation. Most often, folks won’t express their point in a simple, crisp sentence. Rather they’ll produce many many paragraphs, triangulating around their key point. Part of the facilitator’s function is finding a simple statement (or, often, a micro-story) that the participant (enthusiastically) agrees captures their point without leaving out any important detail. [I might write more about how to do distillation sometime.] Only after you’ve done that distillation to get to a crisp, if highly conjunctive, statement, can you move on to doing the crux checking.

Getting through each of these steps might take fifteen minutes, in which case rather than four basic moves, this pattern describes four phases of conversation. (I claim that one of the core skills of a savvy facilitator is tracking which stage the conversation is at, which goals have already been successfully hit, and which is the current proximal subgoal. Indeed, the facilitator will sometimes need to summarize the current state of the conversational stack, to help the participants reorient when they get lost.)

There is also a judgment call about which person to treat as “participant 1” (the person who generates the point that is tested for cruxyness). As a first order heuristic, the person who is closer to making a positive claim over and above the default, should usually be the “p1”. But this is only one heuristic.

All of which is to say, in a real conversation, it often doesn’t goes as smoothly as our caricatured example above. But this is the rhythm of Double Crux, at least as I apply it.