Philosophers themselves, as well as scholars and inquirers of all sorts, have long compared philosophy invidiously with the natural sciences, especially contrasting it with physics. Those who were not unkind enough to attribute this to the intellectual inferiority of philosophers were inclined to the view that the problems of philosophy were inherently intractable and insoluble. But Immanuel Kant was convinced that he had a different answer here. He wrote as follows:

Here Kant has put his finger on a sensible and sensitive spot. One salient difference between natural science and philosophy is that science controls its problem agenda and can dismiss awkward questions. If a question is not tractable in terms that science finds convenient, then science can simply reject it as meaningless. It has—or rather takes—control over its question agenda. But philosophy has not been in a position to do this.

Consider an example: “What is the cause of cancer?” “What is the mass of phlogiston?” Science can dismiss the issue with the reply: “There just is no such thing: concern is not a single-cause phenomenon, phlogiston does not exist.” Science can send an entire issue agenda into exile—witness alchemy, astrology, shamanism, and the occult. Even medicine can reject entire ranges phenomenon—as with acupuncture and hypnosis, saying “The day may well come when we can deal with this—but not yet.” But philosophy—unlike science—is not really in a position to eject questions: it has to do the best it can with the questions it confronts. Science can dissolve and reject questions based on erroneous presuppositions. Philosophy has not enjoyed this privilege: It must take the issues at face value and cope with them but has simply struggled on as best it can.

Science—and especially physics—limits its concerns to matters of generality and precision.