§71.1Fr. 71
Ὁ Θ. οὕτως ὁρίζεται τὸ ἀξίωμα "ἀξίωμά ἐστι δόξα τις, ἡ μὲν ἐν τοῖς ὁμογενέσιν ἐὰν ἴσα ἀπὸ ἴσων, ἡ δὲ ἁπλῶς ἐν ἅπασιν. "
Fr. 71 Theophrastus defines the axiom as follows: "An axiom is a certain judgment, the one being in things of the same kind, as in 'if equals from equals', and the other simply in all things."