One of the most important developments in the contemporary social and human sciences is `the turn to language'. The science of language itself –– modern Western linguistics –– ironically, has seemed slow in responding to this language project but has remained largely preoccupied with its perennial search for general notions and rules of the sentence or the text. In the present study, I take up the discourse of linguistic theorising as the focus of attention, especially the ways in which basic assumptions about `language' are formulated and discussed. My aim is to show that the very object of linguistic investigation is a social, discursive construction and that therefore there is a profound kinship of the language of enquiry with enquiry itself. As data I shall be looking at the theoretical writings of Chomsky and Halliday, the leading exponents of formalism and functionalism, respectively. It will be seen that their foundational concepts (such as `cognitive device', `meaning potential') are grounded in and partially constituted by metaphors. It will also be observed that such figuratively engendered concepts serve not only the rhetorical function of justifying one's own practice but also the ideological purpose of excluding rival approaches.