[Zeno said that] “That which does not make something bigger or smaller when it is added or taken away is not real.”

 

ὃ γὰρ  µήτε προστιθέµενον µήτε ἀφαιρούµενον ποιεῖ µεῖζον

µηδὲ ἔλαττον, οὔ φησιν εἶναι τοῦτο τῶν ὄντων

 

From Zeno of Elea, a student of Parmenides.  Famous for paradoxes (he even appears as an interlocutor for Socrates in Plato’s Parmenides).

(Not the Zeno who founded Stoicism)