Some of the most instructive approaches to cognitive semantics explicitly claim that the investigation of particular properties of scientific concept formation belongs, among other things, to their intended applications. In this respect, the present paper attempts to reveal the capability of two very different cognitive semantic theories to account for the structure of theoretical terms in Chomsky's generative linguistics. Firstly, it shows that if the cognitive theory of metaphor were accepted, then in generative linguistics the relevant aspect of theoretical terms would be that they are assumed to be metaphorical expressions which are manifestations of metaphorical concepts. Secondly, if the two-level approach to cognitive semantics were accepted, then in generative linguistics the relevant aspect of theoretical terms would be that they are semantically underdetermined, because they rest on the relation between their semantic representation & their conceptual representation. These two findings yield far-reaching methodological consequences. (András Kertész)