Light came out of this river since—you say Knights? Yes; but it is like a running blaze on a plain, like a flash of lightning in the clouds. We live in the flicker—may it last as long as the old earth keeps rolling! But darkness was here yesterday.
This passage caught my eye from the very beginning. Actually Marlow's whole speech here caught my attention, but not in the way I think it was intended to. I read mainly the fantasy genre and I am also currently writing a fantasy trilogy. In this genre, the terms "light" and "darkness" come up a lot. And even though these terms mean slightly different things in every story, they still follow the lines of people's hearts. Light and darkness almost always refers to their actions, emotions, and motivation. So upon reading this passage, I immediately took it as one, or both, of two meanings. That Marlow was talking about the hearts of men and how there is light but darkness was just here. Or that he was talking about light and darkness as in events that happen.