“The heavens are the most constant thing we know, the skies the most inconstant… Change to us is an omen of death, and only in the timeless can we feel secure…
George Santayana, Soliloquies in England, and Other Soliloquies
Some of the oldest records we have, from the Maya to the Greeks, are star charts. These charts were made to deal with a deep problem of life, a problem involving order, predictability, and according to the ancients, the eternal. The heavens were held to be unchanging, quite distinct from the capricious clouds and wind. You couldn’t depend on the weather—no one could possibly predict what it would do next, and so it had to be propitiated with herded quadripeds. But the stars, the stars, were faithful, always returning to their proper places after the sun dipped behind the world. ‘Maybe’, someone might have thought, ‘the stars can tell me what the clouds will do’.
The distinction between the heavens and our atmosphere was never totally apparent to the ancients. In On the Heavens, Aristotle (a smart guy) was taken with the notion that meteors were atmospheric projectiles; after all, when they land, they’re just rocks1. Sagan explains this more in his Gifford Lectures, saying that while the Greeks held that all matter was composed of four fundamental substances (earth, air, fire, and water), the heavens were made of another kind entirely—the “aether”—a fifth essence from which we derive the word quintessential, which is how we refer to the best example of something. The heavens and the earth were believed to be fundamentally different, and although the line between them couldn’t be drawn, there was no way that rocky clumps belonged up there.
The ancients used the fixed things of life to help them grasp the transitory. Changing seasons often don’t have clear boundaries, but crops need to be farmed with annual regularity, so the solution was to use reference points in the sky whose behavior could be counted on from year to year2. The ancients recorded everything they saw the stars do, and where they went. But it wasn’t a chore—the stars and constellations were named after their gods and heroes. It’s fun to imagine each chart as a new spin on a story, each data point a godly scandal or triumph.
One useful aspect of narrativizing this way is compression: having characters in the cosmos helped those who made star charts meaningfully communicate to farmers when to time their harvests, as in Works and Days, where Hesiod wrote:
“But when Orion and Sirius are come into mid-heaven, and rosy-fingered Dawn sees Arcturus, then cut off all the grape-clusters, Perses, and bring them home. Show them to the sun ten days and ten nights: then cover them over for five, and on the sixth day draw off into vessels the gifts of joyful Dionysus. But when the Pleiades and Hyades and strong Orion begin to set, then remember to plough in season: and so the completed year will fitly pass beneath the earth.”
Those gifts of joyful Dionysus? Wine made from vines pruned when “the shrilly wailing daughter of Pandion, the swallow” appears just before the onset of spring.
Taking direction from the stars to inform our actions blurs the modern distinction between what are now totally different spheres of human thinking: astronomy and astrology. Myth and science were more united back when the theories we believed in resembled Genesis more than the Standard Model. The data the ancients collected were compiled into literal stories with motivated personas, stories that held prescriptions for action as much as they defined natural events. In those days, the cosmic was domestic.
Out of all this emerges the now classic aim of natural philosophy—science and philosophy before their divorce—to get at the fundamental and unchanging features of the world we find ourselves in, to use the resources at our disposal to tease buried secrets from Nature. There was an idea of truth with a capital T, a kind of Truth that compresses and predicts all experience, the discovery of which would end our entire search.
It’s hard not to think that the Truth of natural philosophy exists mostly abstractly, untethered from everyday facts. As humans, we’ve become aware of a certain order to the world, and to make sense of all the noise which contradicts it, we must continue believing in a certain meta-order, that reality possesses order intrinsically. This belief in a meta-order was recognizably religious when it got started, a reflection of the prior belief in a Creator, but the idea that the world is intelligible still persists in this more secular age. It very clearly works.
In a powerful sense, our understanding of the stars mirrors humanity’s process of self-awakening3. We learned not to take appearances at face value, and to always seek more refined explanations of the way things are. The tables and charts the ancients collected were the first steps; now we scan emission spectra to get at the composition of the heavens and watch the shadows of transiting planets on their sun to discover planets like our own. The clouds of appearances, which myths with characters can't help but add to, have always obscured scientific vision, but we learned to look past them.
Although the stuff that fills our immediate experience may be the most prone to change, it’s still comforting that it’s also what we have the ability to change. But what we see only dimly, which we have no ability to act on (yet!), is what ignites our imagination the most. This is why we reach for the stars.
This is at least partly the reason why the field studying weather is now called meteorology.
The First Scientist, Carlo Rovelli. What a treasure trove of science history
Coming of Age in the Milky Way, Timothy Ferriss