Comments on Chomsky's Chapter, "On the Representation of Form and Function"

I would like to focus on two aspects of the framework outlined in Chomsky's paper: (1) the distinction trace/PRO and, in general, the theory of "missing elements"; (2) the types of evidence on the basis of which the language learner fixes the parameters of Universal Grammar and determines core and marked properties of the particular grammar acquired. I discuss some facts that in my opinion significantly support the relevant aspects of the proposed framework. I then make a shorter remark, much less structured and conclusive, on the properties of Logical Form in configurational and non-configurational languages.