On Trails

To find the origin, Moor went looking for the oldest trail on Earth. It led him to the fossil beds of Newfoundland, at a place called Mistaken Point, where the rock preserves marks left by some of the first mobile animals — soft, simple creatures that lived on the seafloor roughly 565 million years ago, before there were legs or eyes or anything we would recognize as a head. Among the impressions is a faint, meandering groove: evidence that one of these organisms moved across the mud in a deliberate line. It may be the earliest trail we have ever found.

The lesson he drew from it is disarmingly basic. A trail begins the moment a living thing needs something that is somewhere else. Food, warmth, a mate, safety — the body reaches toward it, and in reaching, leaves a mark. That first mark is not yet a path. It becomes one only when a second creature reads it and finds it useful enough to follow. A trail, in other words, requires at least two: one to write, one to read. It is the oldest form of communication that does not need a voice.

Between the fossil and the hiker sit the animals, and this is where Moor's investigation gets its richest material. He spends time with the trails of sheep, deer, and especially elephants, whose ancient migratory routes across Africa were so intelligently laid — always finding the lowest pass, the reliable water, the firmest footing — that early human road-builders often simply followed them. Some modern highways trace lines first surveyed, in effect, by animals that could not read a map but could feel a slope through their feet.

The key idea he draws from herds is that a good trail does not require a single smart individual. It emerges from many ordinary ones, each making a mediocre local choice, whose choices average out into something wise. A lone ant wandering is nearly random. But an ant that stumbles onto a shorter route home lays down a little more scent, which pulls a few more ants onto it, which lays down more scent — and within hours the colony has collectively solved a routing problem that no ant understood. The trail is smarter than any of its makers.

Step back from the dirt and Moor's argument opens wide. The trail, he suggests, is a template we have used for almost everything we build together. It is our oldest technology for taking the hard-won experience of many bodies and compressing it into a form the next person can use without repeating the effort. Once you see paths that way, you start finding them where there is no ground at all.

Language works like a trail. A word is a groove worn smooth by millions of mouths, a route to a meaning that we follow without ever having to reinvent it. Roads are literal trails hardened into asphalt, most of them tracing lines that footpaths and cart tracks proposed centuries earlier. The internet, Moor points out, is described in the vocabulary of the trail almost by instinct — we speak of navigating, of pages we visit, of the paths a signal takes through cable laid, often enough, along old railway beds that themselves followed rivers and passes. The medium keeps changing. The logic of the worn line does not.

Moor came off the Appalachian Trail with a blister collection and a question, and the question turned out to be bigger than the walk. The line he had followed so mindlessly for five months was, he learned, the same kind of thing as the groove in the Newfoundland rock, the elephant route under the highway, the word in his mouth, the cable under the sea. All of them are experience made walkable — the labor of many bodies saved up and handed forward, free, to whoever comes next.