The Guardian

But while nature may mete out time’s passage in these horological devices, it takes human observation of the heavens to set them. Even the most precise atomic clock must be periodically tweaked to account for variations in the earth’s rotation. Some clocks, however, are tuned more directly to nature.

You make it (somewhat) arbitrary. Divide the world into 24 time zones, and  slowly force people  — often through colonial might — to abide by one, standard time for an entire wedge. Do it in the name of commerce, of travel, of ease of communication, of  ease . Fast-forward a century and a half, and this rational/irrational time

Allow celestial bodies to set your sleep-wake pattern. Wake with the sun. Know the phases of the moon. Navigate sometimes by the light of the full moon. Navigate sometimes as dawn emerges, or as dusk falls, paying attention to the shifting of your senses as light becomes more, or less, available. Spend time outside, letting your body take cues from

However, what is clear is that our circadian rhythms influence the circadian rhythms of our gut bacteria, and that the circadian activity of the bacteria we accommodate in our gut impacts upon our metabolism.