One of the magnificent technologies we humans have specialized in since the beginning of the agricultural revolution is cultivation. People focus on some small piece of the universe, like an arable valley or a nice spot at the bend of a river, and pull resources from far and wide, gathering them into that one spot. Cultivation means concentration, where the resources that were naturally spread out are gathered together to make something more intense than was otherwise arising. So farms and ranches make more food consistently in a smaller area than the same area of wild land, and cities make more industrial and knowledge products.
Because this is a systems model, it’s morally empty—neither good nor bad, necessarily. It’s considered wholesome to gather up food scraps and lawn trimmings to make compost to amplify the growing power of your garden soil. But unwholesome to tax the poor to starvation in order to build your Versailles or mega-yacht. Both are resource concentration. Think about the defilement the Buddha called craving (taṇhā, literally “thirst”). Our bodies concentrate the nutrients of water, food, air, and other substances into life force. Thirst is natural, so that can’t be directly the defilement. What the metaphor must be talking about is the thirst that is in excess of need.
We have an impulse for cultivation baked into us as living beings, but when no limits are placed on that impulse—when we become unstoppable as a species—we concentrate too much resource, leaving barren wastelands behind, stripped of their own life force. The second Noble Truth, that craving must be uprooted, is telling humans that in order to stop despoiling the world, we must learn to restrain our instinct for endless cultivation. This is called renunciation. Most animals don’t do this willingly, but are held in check by natural forces when ecosystems are at equilibrium.
Many Indigenous cultures knew how to restrain themselves, generally through teaching stories that contain moral limits, like those Robin Wall Kimmerer in Braiding Sweetgrass tells of not taking all of a given plant when you’re foraging. But the Buddha is from an agricultural society, as we were until quite recently (and the metaphor still holds for industrial cultures like ours). He knows what unfettered cultivation looks like, and it already didn’t look good. His solution was a tribal-style culture where renunciation was maintained through social restraints (the monastic code and the precepts for lay people), and finalized through individual cultivation of the heart. The next step in this metaphor is to look at how inner cultivation replaces outer cultivation as we enter onto the path.