He who wants to know too much knows in the end nothing, and he who conversely believes that some things do not concern him, often victimizes himself, when, for example, the philosopher believes that history is dispensable to him.
“But it’s a nice thing, surely, to be familiar with a lot of subjects.” Well, in that case let us retain just as much of them as we need. Would you consider a person open to criticism for putting superfluous objects on the same level as really useful ones by arranging on display in his house a whole array of costly articles, but not for cluttering himself up with a lot of superfluous furniture in the way of learning? To want to know more than is sufficient is a form of intemperance. Apart from which this kind of obsession with the liberal arts turns people into pedantic, irritating, tactless, self-satisfied bores, not learning what they need simply because they spend their time learning things they will never need.
-Immanuel Kant, Logic
While we’re on the subject, here’s another:
-Seneca, Letter 88