I'm referring to "on the one hand... one the other hand"
καὶ τἀγαθὸν μὲν εὔκτητον,
τὸ δὲ δεινὸν εὐεκκαρτέρητον.
μὲν -_- - δὲ - - - "on the one hand - - - on the other hand - - -"
Those two little one-syllable words do a lot of work in ancient Greek and are used all the time to link two phrases/ideas together. They can often be let out of translations and replaced with "but" or even with a semi-colon. But the main idea when they are used is you have this first idea and then, on the other hand, you have this other idea. For complicated grammatical reasons, they cannot come first in a phrase which is why they show up here where they do. But anytime you see μεν in a sentence, look ahead and see if there's a δε that links the two ideas together.