Book 3
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(for there cannot be demonstration of everything), since demonstration must proceed from something, and have some subject matter, and prove something. Thus it follows that there is some one genus of demonstrable things; for all the demonstrative sciences employ axioms.
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On the other hand, if the science of substance is distinct from the science of these principles, which is of its own nature the more authoritative and ultimate?
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The axioms are most universal, and are the first principles of everything. And whose province will it be, if not the philosopher’s, to study truth and error with respect to them?For the answer see Aristot. Met. 4.3.
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(3.) And in general, is there one science of all substances, or more than one?Cf. Aristot. Met. 3.1.6. if there is not one, with what sort of substance must we assume that this science is concerned?
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On the other hand, it is not probable that there is one science of all substances; for then there would be one demonstrative of all attributes—assuming that every demonstrative science proceeds from accepted beliefs and studies the essential attributes concerned with some definite subject matter.
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Thus to study the essential attributes connected with the same genus is the province of the same science proceeding from the same beliefs. For the subject matter belongs to one science, and so do the axioms, whether to the same science or to a different one; hence so do the attributes, whether they are studied by these sciences themselves or by one derived from them.For the answer see Aristot. Met. 4.2.9-10, Aristot. Met. 6.1.
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(v.) Further, is this study concerned only with substances, or with their attributes as well?Cf. Aristot. Met. 3.1.8-10. I mean, e.g., if the solid is a kind of substance, and so too lines and planes, is it the province of the same science to investigate both these and their attributes, in every class of objects about which mathematics demonstrates anything, or of a different science?
