The psalmist voices the actual temptation: “surely the darkness will hide me.” That's not someone else's doubt he's refuting in the abstract — it's his own assumption, spoken honestly, before being corrected. And the correction isn't gentle vagueness; it's total reversal: darkness and light are described as identical to God — “darkness is as light to you.” Not “God can see a little in the dark.” Total equivalence. That's uncomfortable if you've been counting on the dark to keep something private. But it's also the same comfort as the rest of the psalm turned toward a harder application: the presence that guides and holds you in your best and worst moments is the same presence that already sees what you've hidden in the dark — and it hasn't left either time.