Today I am thinking about thresholds – but not physical doorways, gateways, borders, or frontiers. No, I am thinking of thresholds we use to mark the passage of time. Last night I watched a stunning sunset on Playa Tamarindo, and this morning I rose early and made my way to the playa in the dark in order to watch the full moon set over the same waters, just as the sun was beginning to peek above the eastern horizon. It was an unforgettable spectacle.

Ursula Le Guin writes, “A frontier has two sides. It is an interface, a threshold, a liminal site, with all the danger and promise of liminality.” I find the thresholds between day and night, between the presence and absence of the moon, equally infused with danger and promise. And yet in this case the promise lies in the confidence that this is a cycle that will repeat itself. After night, day will come again. The moon, too, will reappear in the eastern sky. And as it wanes into a mere sliver, I know that it will grow again to the bright disk of light I saw in the sky this morning. The tides that made the beach so broad, will soon make it a mere narrow strip.

What we remark most, what we find most enchanting, are the markers, the thresholds we impose on time – sunrise, sunset; the full moon and new moon. In fact, the sun holds its place while our planet slowly, regularly, turns on its slightly off-kilter axis. Likewise, the moon circles our little planet on its regular path, unconcerned with which portions of the globe currently enjoy its soft, reflected light.

It’s all a matter of perception.