I’ve written before about the dichotomy of descriptive vs theoretical sciences, but I’ve recently noticed another apparent dichotomy within theoretical sciences—expansionary vs focusing sciences. Expansionary sciences are those whose domain tends to expand—(neo)classical economics seems to claim all human interaction in its domain; formal semantics now covers pragmatics, hand gestures, and monkey communication—while focusing sciences tend to rather constant domain or even a shrinking one—chemistry today is about pretty much the same things as it was in the 17th century; generative syntactic theory is still about the language faculty. Assuming this is true,^[1]It’s pretty much a tautology that a science’s domain will either grow, stay constant, or shrink over time the question is, whether it reflects some underlying difference between these sciences. I’d like to argue that the distinction follows from how firm its foundations are, and in particular what I’ll call its empirical conjecture.

Every scientific theory, I think, basically takes the form of a conjoined sentence “There are these things/phenomena in the world and they act like this.” The second conjunct is the formal system that give a theory its deductive power. The first conjunct is the empirical conjecture, and it turns the deductions of the formal system into predictions. While every science that progresses does so by positing new sorts of invisible entities, categories, etc., they all start with more or less familiar entities, categories, etc.—planets, metals, persons, etc. This link to the familiar, is the empirical foundation of a science. Sciences with a firm foundation are those whose empirical conjecture can be uncontroversially explained to a lay person or even an expert critic operating in good faith.

Contemporaries of, say, Robert Boyle might have thought the notion of corpuscles insanity, but they wouldn’t disagree that matter exists, exists in different forms, and that some of those forms interact in regular ways. Even the fiercest critic of UG, provided they are acting in good faith, would acknowledge that humans have a capacity for language and that that capacity probably has to do with our brains.

The same, I think, cannot be said about (neo)classical economics or formal semantics.^[2]Now obviously, there’s a big difference between the two fields—neoclassical economics is extremely useful to the rich and powerful since it let’s them justify just about any … Continue reading Classical economics starts with the conjecture that there are these members of the species homo economicus—the perfectly rational, self-interested, utility maximizing agent—and derives theorems from there. This is obviously a bad characterization of humans. It is simultaneously too dim of a view of humans—we behave altruistically and non-individualistically all the time—and one that gives us far too much credit—we are far from perfectly rational. Formal semantics, on the other hand, starts with the conjecture that meaning is reference—that words have meaning only insofar as they refer to things in the world. While not as obviously false as the homo economicus conjecture, the referentialist conjecture is still false—most words, upon close inspection, do not refer^[3]I could point you to my own writing on this, the works of Jerrold Katz, and arguments from Noam Chomsky on referentialsm, or I could point out that one of the godfathers of referentialism, Ludwig … Continue reading, and there is a whole universe of meaning that has little to do with reference.

Most economists and semanticists would no doubt object to what the previous paragraph says about their discipline, and the objections would take one of two forms. Either they would defend homo economicus/referentialism, or they would downplay the importance of the conjecture in question—“Homo economicus is just a useful teaching tool for undergrads. No one takes it seriously anymore!”^[4]Though, as the late David Graeber pointed out, economists never object when homo economicus is discussed in a positive light. “Semanticists don’t mean reference literally, we use model theory!”—and it’s this sort of response that I think can explain the expansionary behaviour of these disciplines. Suppose we take these objections to be honest expressions of what people in the field believe—that economics isn’t about homo economicus and formal semantics isn’t about reference. Well then, what are they about? The rise of behavioural economics suggests that economists are still looking for a replacement model of human agency, and model theory is basically just reference delayed.

The theories, then, seem to be about nothing at all—or at least nothing that exists in the real world—and as a result, they can be about anything at all—they are unmoored.

Furthermore, there’s an incentive to expand your domain when possible. A theory of nothing obviously can’t be justified by giving any sort of deep explanation of any one aspect of nature, so it has to be justified by appearing to offer explanations to a breadth of topics. Neoclassical economics can’t seem to predict when a bubble will burst, or what will cause inflation, but it can give what looks like insight into family structures. Formal semantics can’t explain why “That pixel is red and green.” is contradictory, but it provides a formal language to translate pragmatics into.

There’s a link here to my past post about falsification, because just as a theory about nothing can be a theory about anything, a theory about nothing cannot be false. So, watch out—if your empirical domain seems to be expanding, you might not be doing science any more.