"The fox knows many things, but the hedgehog knows one big thing."
Isaiah Berlin made much of this fragment Archilochus, which contains a beautiful and intuitive distinction. If you want to apply philosophy to understanding our world, there are worse places to start than the difference between hedgehogs and foxes. Platonic realists, who are in search of the structures of things, are like hedgehogs, while nominalists, who doubt that things have distinct structures, are like foxes. Today, foxes are in short supply.
Platonic realism and nominalism are at two ends of a spectrum of views about the structures of ordinary things. When we organize things, saying that this particular object is a chicken and this is a coop, are we pointing to structures that are basically independent of these physical objects, some sort of Chickenness and Coopness? Or are the chicken and the coop primary, and the structures just ways of organizing these objects? What came first, the chicken or the Chickenness?
On the platonic realist end of the spectrum, Plato taught that Chickenness exists separately from actual chickens. Chickenness is an abstract object, a Form, so independent of actual chickens that even if they all died, the Form would remain as the essence of any potential chickens. At the other end of the spectrum, nominalists think that only individual objects are real, for there is nothing that all chickens share. Between any two individuals (or between their DNA, or between their atomic structure) we discover differences as well as similarities. Chickens resemble each other in the difficult-to-articulate way that family members resemble each other, even though there is no single, family face.
Let me lay my cards on the table. I am a nominalist. I think the best reason for being a nominalist is reflecting on your own ideas. When you consider Chickenness, what colour is it? It can't be white, or red, or black, or any colour of actual chickens, because it must somehow contain all these colours at once. Is it a big chicken or a small one? Well, both at once. Is it shaped like a bantam or a silkie or a Polish chicken - it must be like all of them, without the particularities of any of them. Now I ask you, do you have an idea of Chickenness in mind that meets all these criteria? I don't. Take away the colour, the shape and the size, and I find I'm not thinking of anything at all. I conclude that there is no such thing as Chickenness. And that is why I am a nominalist.
You may not be convinced by my quick resolution of this ancient debate. I may have better luck convincing you that the debate matters. Suppose you are trying to solve a problem. It does not matter whether you are trying to run a company or a state, learning to get along with girls or figuring out how to fix cars. Hedgehogs and foxes have different prescriptions for doing so. The platonic realist tells you that you need to figure out what all states or companies or girls or cars have in common, and work downward towards your problem from those general principles. You need to know one big thing, and then you can apply it to individual cases. The nominalist thinks that you need to avoid abstractions and build up your experience, whether that be experience of running things, getting along with girls or fixing cars. Unfortunately, experience requires time and exposure to the world. The hedgehog thinks that when you get to the abstraction, the messy reality falls away. The fox thinks that reality is messy, and ignoring the mess means ignoring the world.
What emerges are two very different pictures of human success. On the one hand, you have the platonic theoretician. He is searching for the universal behind the particular. His skill is, as we would say today, managerial, and consequently transferrable between positions. And because his skill is detached form the world, a gift from the gods, even a child can be a theoretician wunderkind. On the other hand, the nominalist picture of success is mastery. The master gains his knowledge slowly, through repeated exposure to reality, through what Aristotle would call experience of particulars. Much of the master's knowledge cannot be articulated, or if it can, only in the form of "you'll understand when you've been at this as long as I have." There are no shortcuts to mastery, which is why children are never masters.
We are living through the triumph of the theoretician, and the consequent eclipse of the master. Just think of how many times in a day you witness one big thing trump many things. The theoretician management consultant who 'streamlines' a task over the objections of the experienced foreman. The education theoretician lectures the weathered teacher about the latest ways of teaching. The freshly minted theoretical doctor (once upon a time, there were also empirical doctors) scoffs at the ministrations of the nurse. Theory replaces mastery, though it is not obvious that work, school or medicine is much improved.
Because the triumph of the theoreticians is so complete, and because it bubbles up from such a deep philosophical wellspring, it blinds us to alternative possibilities. We see this at work. Finance, business and bureaucracy are almost entirely concerned with abstractions, to the wordless pain of many who toil in these areas, but even they cannot imagine a return to a world before metrics and quarterly reports. We see this in natural science, where we discount the mastery of the laboratory and imagine that the scientist's real contribution is flashes of insight into some one big thing. That is also why we tolerate economics, as it lurches from one big disastrous prediction to the next. Even in politics, theory is desired above all things. One of the criticisms routinely leveled at populist leaders is that their guiding doctrines are not, and perhaps cannot be articulated. And since we imagine that the world tends toward theory, we are puzzled and a perhaps little embarrassed by the persistence of mastery in folk remedies, nursing, the wisdom of the old (we prefer ‘wise’ children), craft, combat, tradition and religion.
The fox knows many things, but the hedgehog knows one big thing. Platonic realists are ever on the search for the one big theory that will unlock the world. The fox knows that the world is not like that. But we all live in hedgehog country now.