# Types of Knowledge

This is a system for sorting types of knowledge. There are many like it, but this one is mine.

First, there is knowledge you could regurgitate on a test. In any sane world this wouldn’t be called knowledge, but the school system sure looks enthusiastic about it, so I had to mention it. Examples:

*   Reciting the symptoms of childbed fever on command 
*   Reciting Newton’s first law of motion
*   Reciting a list of medications’ scientific and brand names
*   Reciting historical growth rate of the stock market
*   Reciting that acceleration due to gravity on Earth is 9.807 m/s²

Second, there is engineering knowledge- something you can repeat and get reasonably consistent results. It also lets you hill climb to local improvements. Examples:

*   Knowing how to wash your hands to prevent childbed fever *and doing so*
*   Driving without crashing
*   Making bread from a memorized recipe.
*   What are the average benefits and side effects from this antidepressant?
*   Knowing how much a mask will limit covid’s spread
*   Investing in index funds
*   Knowing that if you shoot a cannon ball of a certain weight at a certain speed, it will go X far.
*   Knowing people are nicer to me when I say “please” and “thank you”

Third, there is scientific knowledge. This is knowledge that lets you generate predictions for how a new thing will work, or how an old thing will work in a new environment, without any empirical knowledge.

Examples: 

*   Understanding germ theory of disease so you can take procedures that prevent gangrene and apply them to childbed fever.
*   Knowing the science of baking so you can create novel edible creations on your first try.
*   Knowing enough about engines and batteries to invent hybrid cars.
*   Actually understanding why *any* of those antidepressants works, in a mechanistic way, such that you can predict who they will and won’t work for.
*   A model of how covid is spread through aerosols, and how that is affected by properties of covid and the environment.
*   Having a model of economic change that allows you to make money off the stock market in excess of its growth rate, or know when to pull out of stocks and into crypto.
*   A model of gravity that lets you shoot a rocket into orbit on the first try.
*   A deep understanding of why certain people’s “please”s and “thank you”s get better results than others.

Engineering knowledge is a lot cheaper to get and maintain than scientific knowledge, and most of the time it works out. Maybe I pay more than I needed to for a car repair; I’ll live (although for some people the difference is very significant). You need scientific knowledge to do new things, which either means you’re trying something genuinely new, or you’re trying to maintain an existing system in a new environment.

I don’t know if you’ve noticed, but our environment was changing pretty rapidly before a highly contagious, somewhat deadly virus was released on the entire world, and while that had made things simpler in certain ways (such as my daily wardrobe), it has ultimately made it harder to maintain existing systems. This *requires* scientific knowledge to fix; engineering won’t cut it.

And it requires a lot of scientific knowledge at that- far more than I have time to generate. I could trust other people’s answers, but credentials and authority have [never looked more useless](https://www.lesswrong.com/posts/h4vWsBBjASgiQ2pn6/credibility-of-the-cdc-on-sars-cov-2), and identifying people I trust on any given subject is almost as time consuming as generating the answers myself.  And I don’t know what to do about that.