A nice passage from Jean Grondin’s bio, Hans-Georg Gadamer:
“We never understand anything completely, never quite manage to cope with this world, every truth is only a half truth, all certainties are provisional, but in this twilight state all human understanding takes place. Understanding is, so to a speak, a flickering wakefulness in a night that envelopes us more completely than that momentary brightness. Between these two poles of wakefulness and night, Heidegger’s whole thought vacillates. Perhaps he emphasised the darkness in his gloomiest moments” (p.104).