Lavrentivs wrote:<We> who understand them must speak more clearly about these things.
I expected imperfect, since I assumed that the understanding referred to was an enduring state. Perhaps: we who have understood them?
Ahh. You are mixing lexical aspect — the inherent meaning of the verb — and grammatical aspect, which is related to how we organize our discourse. I can say, "I was sleeping last night" or "I slept last night." Both sentences describe situations of identical duration. The different aspect choices are about presentation
, not (necessarily) actual duration.