The concept of logical form has had almost as many ups and downs in language theory as the Dow Jones in Wall Street. It played an important role in the early decades of this century in the philosophy of language of the middle period Russell (1914) and of the early Wittgenstein (1929).¹ Later, it has been appealed to by Davidson (1984) and Quine (1960).² It was not much in evidence in Chomsky's published oeuvre before the late seventies. Recently, however, it has been restored to a place of honor in the linguistic work inspired by Chomsky or carried out by him. Indeed, most of the work that has been labelled "Government and Binding Theory" can be viewed as dealing essentially with the logical forms of natural-language sentences.³