"The present book is our latest contribution to the history and philosophy of linguistics. It continues a series of previously published monographs and papers which have attempted to discuss foundational problems of linguistic inquiry systematically. This long-term programme aims at the clarification of issues which have not been dealt with extensively in the literature we know, although their relevance seems to be beyond doubt. Among others, the topics we have already tackled include the structure and the function of linguistic data and evidence; the structure of linguistic theories; the peculiarities of thought experiments and real experiments in linguistics; fallacies in linguistic theorising; the relation between the social and the cognitive factors that shape the content of linguistic theories; the historiography of linguistics etc. In raising these and further issues, we have proceeded parallelly on two levels. First, we have based our metatheoretical research on a great number of detailed case studies in the fields of generative syntax, cognitive semantics, pragmatics, and phonology. Second, we have put forward a metatheoretical framework - called the p-model - capable of accounting for the foundational problems at hand and of analysing the subject matter of diverse case studies"--.