Full Idea
All demonstrative science [apodeiktike episteme] is concerned with three things: what it posits to exist (the kind), the axioms (primitives basic to demonstration), and the attributes.
Clarification
'Axioms' are unquestioned assumptions
Gist of Idea
All demonstration is concerned with existence, axioms and properties
Source
Aristotle (Posterior Analytics [c.327 BCE], 76b12)
Book Reference
Aristotle: 'Posterior Analytics (2nd ed)', ed/tr. Barnes,Jonathan [OUP 1993], p.15