Since literal darkness is both the trigger and the metaphor for almost all the other kinds, this seems like the place to start. There is so much folklore about darkness, so much baggage packed by people whose hopes and fears are far different from mine, that it seems important to pay attention to the arrival of it for once, letting curiosity take the place of evasion. Even if it is just for one night, what can I learn about darkness by lying in wait for it like this?

According to the U.S. Naval Observatory, every day ends with three different twilights. Civil twilight begins a little before dark, when you first notice that it is time to use the headlights on your car. For some, this realization does not come until the last three approaching cars have blinked their headlights at you. Mild confusion ensues—did you leave your pocketbook on top of the car again? —until the brain puts dark and dark together and turns the headlights on.

Civil twilight is over by the time I take up my post in the yard. The moon is at half-mast, lying low over the darkening horizon. It will be full tonight—what the first people who lived here called a Grain Moon since the hay in the field is ripening for the second time this summer. The sky still has enough light in it that every now and then I see something that looks like a miniature biplane flying past—either a dragonfly or a pair of insects into adventurous sex. The bat has apparently called it a night.

Nautical twilight comes next, when the brightest stars are visible enough to steer by. That means Venus will be a front-runner, showing up low over the western horizon while the cicadas kick up their chorus of thrumming in the woods. There are fewer crickets tonight, but they send their messages too, along with a pair of night birds trying to find each other in the dark. When the compressor for the air conditioning in the house turns on, I feel apologetic. I had no idea how loud it was out here, clearly interrupting a whole valley full of creatures that are trying to say something to one another.

Above all our heads, the arrival of nautical twilight is not looking good. The thin gray blanket of clouds has grown, covering the moon along with the rest of the sky. What do people do, on nights like this, in countries where the start of a festival or a month of fasting depends on a clear view of the moon? Every now and then it shows through the clouds that are moving across its face. One moment it looks like the eye of a hawk in profile. The next it looks like the eye at the top of the pyramid on a dollar bill. Why does it never look simply like the moon behind clouds? I do not know. All I know is that I never tire of pulling the moon to earth by likening it to something I know down here.

When the thickening clouds leave no doubt that nautical twilight will not be happening tonight—much less astronomical twilight, which begins when even the faintest stars are visible—I think that I should go inside, but I do not go inside. The sky changes every couple of seconds. The breeze is slight but delectable. The sounds come from all directions at once. If I put out my hand to touch the flagstones beneath my raft, I can still feel the heat of the day in them, as if the earth were a sleeping animal giving off warmth.

To go inside would be like putting down a glass of cool spring water to go drink a store-brand cola. It would be like blowing out a pearl-colored candle to go read by a compact fluorescent light. Why would someone do that? The only reason I can think of is because she does not know what to do with so much night, especially since nothing she can do in it counts as productive, useful, or even moderately aerobic.