Full Idea
Demonstrations are both from a starting-point and have a sort of end, namely the deduction or the conclusion.
Gist of Idea
Demonstrations move from starting-points to deduced conclusions
Source
Aristotle (De Anima [c.329 BCE], 407a25)
A Reaction
A starting point has to be a first principle [arché]. It has been observed that Aristotle explains demonstration very carefully, but rarely does it in his writings.
Book Reference
Aristotle: 'De Anima (on the psuche)', ed/tr. Reeve, C.D.C. [Hackett 2017], p.11
Related Idea
Idea 24047 An account is either a definition or a demonstration [Aristotle]