Towards a new empiricism for linguistics

The view of linguistics which we will consider in this chapter is empiricist in the sense explored in Chapter One of this book:1 it is epistemologically empiricist, rather than psychologically empiricist; in fact, it is a view that is rather agnostic about psychology — ready to cooperate with psychology and psychologists, but from a certain respectful distance. It is empiricist in the belief that the justification of a scientific theory must drive deep into the quantitative measure of real-world data, both experimental and observational, and it is empiricist in seeing continuity (rather than rupture or discontinuity) between the careful treatment of large-scale data and the desire to develop elegant high-level theories. To put that last point slightly differently, it is not an empiricism that is skeptical of elegant theories, or worried that the elegance of a theory is a sign of its disconnect from reality. But it is an empiricism that insists on measuring just how an elegant a theory is, and measuring how well it is (or isn’t) in sync with what we have observed about the world. It is not an empiricism that is afraid of theories that leave observations unexplained, but it is an empiricism that insists that discrepancies between theory and observation are a sign that more work will be needed, and sooner rather than later. And it is an empiricism that knows that scientific progress cannot be reduced to mechanistic procedures, and even knows exactly why it cannot. Thus this chapter has four points tomake: first, that linguists can and shouldmake an effort tomeasure explicitly how good the theoretical generalizations of their theories are; second, that linguists must make an effort to measure the distance between their theories’s predictions and our observations; third, that there are actually things we working linguists could do in order to achieve those goals; and fourth, that many of the warnings to the contrary have turned out to be much less compelling than they seemed to be, once upon a time. The perspective spelled out is thus non-cognitivist, though by no means anti-cognitivist, and I emphasize to the reader that our empiricism is not one that in any sense prefers data over theory. And I do not wish to argue that this is the way, the only way to do linguistics; there are many ways to do linguistics. But in recent decades, and especially within theoretical linguistics, a view has become so widespread that it passes now for uncontroversial: that the reality claimed by a linguistic theory is the same reality claimed by a psychological theory, and I wish to respectfully disagree with that view, and suggest that it is a serious oversimplification, at the very least. The main focus of this chapter is the notion of Univeral Grammar: henceforth,UG. From a methodological point of view, UG is the set of assumptions we bring to the design of a grammar for a language. From a psychological point of view, UG is a model of the initial cognitive state of a language learner before any of the data from a particular language have been made available to the learner. I will focus on the methodological sense, for reasons that we will see, and I will offer my reasons for believing that an empirically empty version of UG is available to us, and may well be just what we need, at least for some parts of linguistics. That sounds a bit mysterious (after all, what could it mean to speak of an empirically empty UG? ), but this will become clearer as we proceed. The two most important points that I shall argue are, first, that we need a quantitative account of theory-confirmation, and second, that we should not treat theoretical mechanisms that we put in Universal Grammars as cost-free. I will suggest, on the one hand, that probability can be understood as the quantitative theory of evidence, and, on the other hand, that probability theory offers us a more comprehensive and concrete way to understand the fundamental problem of induction, which is to say, how one passes from knowledge of a finite number of particulars to a generalization, which, typically, allows us to infer an infinite number of conclusions, almost all of which have not yet been tested. One of the consequences of this perspective is the perhaps surprising principle that the value of a theoretical innovation is neither more nor less than the amount of information it would take to (merely) stipulate its intended consequences.