Now you can apply yourself voluntarily to reading and learning, but you cannot really apply yourself to thinking: thinking has to be kindled, as a fire is by a draught, and kept going by some kind of interest in its object, which may be an objective interest or merely a subjective one. The latter is possible only with things that affect us personally, the former to only those heads that think by nature, to whom thinking is as natural as breathing, and these are very rare. That is why most scholars do so little of it.
Arthur Schopenhauer, On the Suffering of the World
