τὰ ἀφανῆ τοῖς φανεροῖς τεκμαίρου → analyze the unknown based on the known
Dor. for ἦμεν, 1pl. impf. of εἰμί (
A sum).
ἦμες: Δωρ. ἀντί ἦμεν, = εἶναι, ἀπαρ. τοῦ εἰμί.