• Martial arts are individual pursuits. They are typically practiced in a social context, yes, students practicing together, masters passing their wisdom on to students. But they’re mostly not about fighting together, just training. Rationalists, like other humans, need to work together to complete large projects.
• Martial arts are personal. They are specifically about what a human mind can do with a human body. Rationalists are encouraged to make and use tools.
• Martial arts are only good for one thing: physical conflict with other humans. Rationality is broadly applicable, in almost any context or for any purpose.
• It’s straightforward to identify skilled martial artists by holding fighting tournaments. What sort of tournament do you hold to test rationalists? Assessing rationality in humans is Hard.
• Martial arts are competitive. They are about becoming the best fighter (comparative) and not about becoming the true fighter (absolute), whatever that would even mean.
• In martial arts, your opponents are always human.

Instead I propose a metaphor of rationality as the mental toolkit you use to understand the world, plan, and make decisions.  Now, a toolkit is not the single perfect true metaphor for this purpose, but it does have one very nice property that the martial arts metaphor does not: other metaphors for rationality are themselves part of the toolkit.

Mental tools (or mental technologies) like Bayes’ Theorem or Postmodernism can be invented. They can be passed from person to person, but they’re no good unless you know how to use them. They can be designed for many purposes or for very specific purposes. Your capabilities expand as you acquire a broader range of tools, and you can produce finer work with more specialized tools.

You can use tools to build better tools.

You can use tools to build.

One other nice property of the toolkit metaphor is that metaphor is itself a part of the toolkit of rationality, as is self-reference.