Liquid Knowledge

Most people would agree that the content of the classes one takes is not usually the most important thing learned from school. In fact, most students forget over 95% of what they learn in classes after just three days.

It’s skills like time management and critical thinking that are the real valuable things learned in school. What’s valuable about these skills is that they are liquid — they are easily transferrable across domains and industries and not specific to any particular subject.

For most people, memorizing the steps in the Krebs Cycle, while necessary for getting a good grade in AP Bio, will not transfer out of the class. In other words, it’s knowledge that isn’t liquid and won’t transfer across other domains.

Elon Musk puts it like this:

“It is important to view knowledge as sort of a semantic tree — make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to.”

Musk is referring to liquid knowledge here. There’s no point in memorizing all the taxonomic ranks of biology before you understand the theory of evolution. You might be able to use pneumonic devices to memorize them successfully for a test, but you won’t have any context, or “trunks”, for the knowledge and it won’t stick.

Another name for these “trunks” of knowledge is mental models. Mental models are just large chunks of knowledge that represent some understanding. You have mental models for everything you do from brushing your teeth to starting your car and you use them every day.

While our mental models inform our understanding of the world and everything we do, they are implicit for most of us — that is, we operate them subconsciously. Making these models explicit provides us the opportunity to understand our own understanding of the world.

By focusing on acquiring liquid knowledge, we can build robust mental models that improve our understanding of the world and our ability to think clearly.

For some examples of valuable mental models that contain liquid knowledge, check out this list by James Clear.

Can’t wait till we start teaching game theory in grade school :)