 Qua practical scientist of nature, the physician absolutely presupposes a handle or manipulability conception of causation which makes it possible to intervene in nature to achieve certain intended results, i.e., to restore health. This sense of causation is at work in statement such as “The cause of malaria is the bite of a mosquito” (EM 1998: 299) or “the cause of a man’s sweating is a dose of aspirin” (EM 1998: 299). The presupposition is absolute because it could not be questioned without at the same time undermining the kind of inquiry it makes possible. Absolute presuppositions in this respect differ from relative presuppositions. A physician prescribes a dose of aspirin on the assumption it will cause a patient to break into a sweat. This presupposition is relative because it could potentially be overthrown by future research. But the underlying conception of causation is a condition sine qua non for practising medicine. It is these absolute presuppositions that philosophy seeks to uncover by regressing from propositional answers to the questions they are answers to, and from the questions to the presuppositions which must be made for the questions to arise.