Whatever their precise cognitive status is, principles of linguistic organization are some part or other of our cognitive apparatus. Just what would such “principles of linguistic organization” involve? In particular, they would involve [...]: - central and peripheral members - basic-level object at the center - conventional mental images - knowledge about conventional mental images - Image-schema transformations - Metonymy applied to mental imagery - Metonymy applied to domains of experience - Metaphors (which map domains into other domains) These mechanisms are needed, no matter whether one calls them linguistic or not. Moreover, they appear to be the kinds of things that one would tend to call conceptual-mental images and image transformations do not appear to be merely linguistic. Moreover, linguistic categories can be used in nonlinguistic tasks, as Kay and Kampton (1984) have demonstrated [...]. But whether they are used in nonlinguistic tasks or not, linguistic categories are categories-and they are part of our overall cognitive apparatus. Whether or not one wants to dignify them with the term “conceptual” or not, linguistic categories are categories within our cognitive system and a study of all categories within our cognitive system will have to include them.
- Lakoff (1987), a pag.110

Linguistic categories are among the kinds of abstract categories that any adequate theory of the human conceptual system must be able to account for. Human language is therefore an important source of evidence for the nature of cognitive categories.
- Lakoff (1987), a pag.180