ποταμῷ γὰρ οὐκ ἔστιν ἐμβῆναι δὶς τῷ αὐτῷ → it is impossible to step twice in the same river, you cannot step twice into the same rivers
λόγος, τέκμαρσις, εἰκασία, δόκησις, δόξασμα, προσδοκία, ὑπόληψις, ὑπόνοια, εἰκασμός, καταστοχασμός, στοχασμός, στόχος, ὑπόθεσις