In social science, Thatcher’s philosophical position [that “There is no such thing as society; there are individual men and women, and there are families”] goes by the name of methodological individualism, which claims that until one has succeeded in explaining some social phenomenon—the popularity of the Mona Lisa or the relation between interest rates and economic growth—exclusively in terms of the thoughts, actions, and intentions of individual people, one has not fully succeeded in explaining it at all. Explanations that ascribe individual psychological motivations to aggregate entities like firms, markets, and governments might be convenient, but they are not, as the philosopher John Watkins put it, “rock bottom” explanations.

Unfortunately, attempts to construct the kind of rock-bottom explanations that methodological individualists imagined have all run smack into the micro-macro problem. In practice, therefore, social scientists invoke what is called a representative agent, a fictitious individual whose decisions stand in for the behavior of the collective.

…By ignoring the interactions between thousands or millions of individual actors, the representative agent simplifies the analysis of business cycles [for instance] enormously. It assumes, in effect, that as long as economists have a good model of how individuals behave, they effectively have a good model for how the economy behaves as well.

…In practice, however, methodological individualists have lost the battle, and not just in economics. Pick up any work of history, sociology, or political science that deals with “macro” phenomena, like class, race, business, war, wealth, innovation, politics, law, or government, and you will find a world populated with representative agents. So common is their use in social science, in fact, that the substitution of a fictitious individual for what is in reality a collective typically happens without so much as an acknowledgement, like the magician placing the rabbit in the hat while the audience is looking elsewhere. No matter how it is done, however, the representative agent is only and always a convenient fiction. And no matter ho we try to dress them up in mathematics or other finery, explanations that invoke representative agents are making essentially the same error as commonsense explanations that talk about firms, markets, and societies in the same terms that we use to describe individual people.

—Duncan Watts, Everything I Obvious* *Once You Know the Answer, 65-67

Snipped for later. I’m not a sociologist — are there examples of fields within sociology and other social sciences which aggressively tackle this “micro-macro” problem? Most of the theory I engage with takes representative agents as a matter of course.