(1)　b.　An outcome β of an experiment confirms a prediction γ iff β is in accordance with γ; β disconfirms γ otherwise.

We should certainly address what is meant by an 'experiment' here. The failure to articulate the basic structure an experiment in generative grammar (at least in the domain where we deal with 'meanings') seems to be a serious shortcoming of the paper when its stated goal is to illustrate how generative grammar is, or can be, an empirical science. A more satisfactory work would therefore contain (i) explicit characterizations, as it is deemed appropriate and relevant, of concepts such as observations, generalization, theory/hypothesis/analysis, predictions, falsifiability, and experimental designs and (ii) their concrete illustration on the basis of specific empirical materials.