Have you ever heard a legal scholar criticize a doctrine because it does several different things, but it isn’t really good at any one of those things? That kind of criticism of a doctrine is much less common from a judge. Why is that? If you want the answer to these questions, there’s a Green Bag article I wrote a few years ago called On Doctrines That Do Many Things. It starts this way:
Every kitchen has two kinds of tools. Some of these tools do many things well, like a chef’s knife. Other tools do only one thing, but they are meant to do that one thing exceedingly well, like a garlic press. The same distinction appears in legal doctrines. Some doctrines do one thing and are meant to do it very well. Others do many different things. They serve multiple functions, though perhaps all imperfectly.