The title of the book that I am working on now is Language Faculty Science: how it becomes an exact science―a proposal and illustration.

The draft of Chapter 1 starts as follows, disregarding the font formatting and the footnotes.

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1.1. The Goal
It is an indubitable fact that, once they have reached a certain maturational stage, the members of the human species, barring any serious impairment, are able to produce and comprehend sentences of the language that they are exposed to. One of the most fundamental working hypotheses adopted in the present work is that there exists the language faculty underlying this ability of ours. The existence of the language faculty has been assumed by many and it has been the point of departure of Chomsky's research program although there is also a contrary view accepted by many, as indicated in N. J. Enfield's recent (2010) review article in Science "Without Social Contexts?." Chomsky has maintained over the years that we should approach the language faculty just as natural scientists approach their subject matters. It has, however, remained unclear how hypotheses about the language faculty can be put to rigorous empirical test. The problem manifests itself most acutely once we consider how the hypothetico-deductive method―the most commonly acknowledged hypothesis-testing "method" in a mature science such as physics―can be applied to language faculty science.

The present work articulates how predictions about the language faculty can be deduced from our hypotheses, how such predictions can be tested against experimental results, what should count as the relevant data in language faculty science, whether and how such data can be of a categorical nature, what kind of experimental design would maximize the significance of the experimental results, how we can make various aspects of experimental devices maximally effective, how rigorous a match we could expect between the prediction and the experimental results, along with many other related issues. It attempts to pursue and defend the thesis that it is possible to investigate the language faculty by applying the hypothetico-deductive method, i.e., by rigorously comparing the predictions deduced by our hypotheses with experimental results and observations. Insofar as we can carry this out successfully, with compelling empirical demonstration, that will constitute support for the existence of the language faculty.

1.2. Reproducibility and measurability

In physics, what is predicted and compared with experimental results (or observations) is something that is measurable (ultimately in terms of temporal and spatial values). The measurability of the relevant "data" is what makes it possible to compare a prediction with an experimental result and also to determine how much reproducibility there is to the experimental results and observations. Given that reproducibility and measurability are two prerequisites for effectively adopting the hypothetico-deductive method, it follows that predictions in language faculty science must be about something reproducible and measurable as long as we adopt the hypothetico-deductive method.

One may wonder whether it is reasonable to apply the hypothetico-deductive method to research concerned with the language faculty. After all, it is commonly understood that the "predictions" in fields outside the extremely limited domains of inquiry including physics are about differences and tendencies and that it is not possible to deduce point-value predictions in such fields. One may thus object that physics is not the right field for us to turn to as a model of our research program. One may also point out that the hypothetico-deductive method is not the only method adopted even in physical sciences. My response, briefly put, is: if it is possible to get to know something by following the hypothetico-deductive method, why would one want to adopt a less rigorous method?
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