The Best of LessWrong

In a universe with billions of variables which could plausibly influence an outcome, how do we actually do science? John gives a model for "gears-level science": look for mediation, hunt down sources of randomness, rule out the influence of all the other variables in the universe.

Trees are not a biologically consistent category. They're just something that keeps happening in lots of different groups of plants. This is a fun fact, but it's also an interesting demonstration of how our useful everyday categories often don't map well to the underlying structure of reality.

Most problems can be separated cleanly into two categories: things we basically understand, and things we basically don't understand. John Wentworth argues it's possible to specialize in the latter category in a way that generalizes across fields, and suggests ways to develop those skills.