It's hard to pinpoint - sometimes at all - the genesis of ideas. The Greeks is the general cry, but that usually includes the western Mediterranean, and takes no account of the perhaps 6,000 years of thinking preceding them. Thales, e.g., famously predicted an eclipse. Apparently no one knows how, but he likely didn't just get out of bed one morning and predict it.

So I will assign it to Plato in his Phaedrus, wherein he attributes it to Socrates: " I am myself a great lover of these processes of division and generalization; they help me to speak and to think. And if I find any man who is able to see "a One and Many" in nature, him I follow, and "walk in his footsteps as if he were a god."

I suppose that people then and before were capable of genus, species thinking, which is what Plato means, but that in practice they didn't. And to me this makes sense. We see a lion, e.g., and think Panthera leo, and suppose ourselves done. The ancient, no doubt, thought (in translation of course), "Yikes, a f**king lion, where the f**k is my spear?!" In other words, particulars all the way down. Sense?

it's a heuristic or a model that has predictive power over a range of content and circumstance.

Pointing a word (or other symbol) at more than one thing.

I suppose that people then and before were capable of genus, species thinking, which is what Plato means, but that in practice they didn't. — tim wood

Biologists constructing a taxonomy, ancient philosophers an account of nature's essence, prehistoric humans a spear, animals a nest, are these all analogous as conceptual or neural structuring, a cognition of particulars into functional kinds?

Perhaps some dynamic of neural or otherwise substantiated structuring exists that is common to all the most cognitive species, responsible for grouping of particulars into kinds as a basic conceptual phenomenon, in behaviors as diverse as mate selection, social stratifying, nest-building, technological inventiveness, naming, philosophical reasoning towards superordinate essences and fundamentals, scientific classification, theoretical modeling, and so on. Maybe the act of generalizing will one day be correlated primarily with tissues of the cerebrum, a brain structure which is unique to the biggest macroscopic animals, comprised of the most intricately interconnected and rewritable neuronal wiring and synesthesia, possibly responsible for generating an experience of so to speak “knowing what you are doing” psychically, the integrating of vastly dispersed perceptual phenomena via both more or less inferential reasoning and various degrees of self-awareness, a process of association-making that facilitates behavioral priming.

Do I know what I'm doing yet? lol