If we have Epicurus, On Nature, Book 34, P.Herc. 1431, col. 16: Ἀ[να]γκαῖον αὐταῖς ὑπάρχειν κατὰ τὰς πρὸ[ς] ἀλλήλας κρούσεις – ὡς ἐν τῆι πρώτηι γραφῆι εἴρηται – οὐθὲν ἧττον παρὰ τὰς [ἐξ] ἡμῶ[ν], τ[ις] σ[υμ]μετρ[ία] αὐτ[αῖ]ς γίγνε[σθαι]...
I think it can be translated: It is necessary for [atoms] to exist with collisions with each other – as it has been said in the first writing – nevertheless, from those [atoms] that come from us, a certain symmetry with them does occur...
Which I think can be interpreted: You do not feel the atoms that form your body moving because in a certain way they are all moving together.
Happy for any other ideas. At lot hangs on σ[υμ]μετρ[ία], probably too much.