The moon looks wonderful in this warm evening light, just as a candle flame looks beautiful in the light of the morning. Light within light. [...] It seems to me to be a metaphor for the human soul, the singular light within the great general light of existence. (1.8.11-12)
Light is a recurring image in Gilead, a bright sign of John Ames's graceful and hopeful perspective on life, the universe, and everything else. To him, the individual is a light, a thing of beauty, someone to love to matter what. No matter how rotten people make it, the world is good, and they, at base, are good.
"It has all been one day, that first day," he writes later. "Light is constant, we just turn over in it" (1.20.14). You could say that darkness is also constant, but this doesn't occur to Ames, or if it does occur to him, he doesn't mention it. He probably wouldn't think it worth mentioning. To him, light is beautiful, as the world is. Perhaps what's more important to note is that light is the source of light, and darkness is simply the absence of light. That's what John Ames knows.
Ames isn't ignorant or naïve; he's seen some of the worst humanity can do. He knows evil inside and out. And yet he keeps his focus and attention on the light of life, the beauty of it, the hope it has to offer. He's dying, but, as the saying goes, he's already seen the light.
Sorry, we couldn't help ourselves.