Moreover, if relativity hasn't been invented yet, it makes sense to stick with Newtonian gravity as the _best_ theory you have _so far_, even if there are a few anomalies [like the precession of Mercury](https://en.wikipedia.org/wiki/Tests_of_general_relativity#Perihelion_precession_of_Mercury) that it struggles to explain.
-The same general principles of reasoning apply to psychological theories, even though psychology is a much more difficult subject matter and our available theories are correspondingly much poorer and vaguer. There's no way to make precise quantitative predictions about a human's behavior the way we can about the movements of the planets, but we still know _some_ things about humans, which get expressed as high-level generalities that nevertheless admit many exceptions: if you don't have the complicated true theory that would account for everything, then simple theories plus noise are better than _pretending not to have a theory_. As you learn more, you can try to refine more complicated theories that explain some of the anomalies that looked like "noise" to the simpler theory.
+The same general principles of reasoning apply to psychological theories, even though psychology is a much more difficult subject matter and our available theories are correspondingly much poorer and vaguer. There's no way to make precise quantitative predictions about a human's behavior the way we can about the movements of the planets, but we still know _some_ things about humans, which get expressed as high-level generalities that nevertheless admit many exceptions: if you don't have the complicated true theory that would account for everything, then simple theories plus noise are better than _pretending not to have a theory_. As you learn more, you can try to pin down a more complicated theory that explains some of the anomalies that looked like "noise" to the simpler theory.
+
+What does this look like for psychological theories? In the crudest form, when we notice a pattern of traits that go together, we give it a name.
-What does this look like for psychological theories?
[If a category seems to come into types, you can reify those as separate sub-categories, like bipolar I and II. The idea that there's something to the idea that bipolar I and II are "different", is s]