[…] in the technical sense, linguistic theory is mentalistic, since it is concerned with discovering a mental reality underlying actual behaviour.
- Chomsky (1969), a pag.4

Mentalistic linguistics is simply theoretical linguistics that uses performance as data (along with other data, for example, the data provided by introspection) for the determination of competence, the latter being taken as the primary object of its investigation. The mentalist, in this traditional sense, need make no assumptions about the possible physiological basis for the mental reality that he studies.
- Chomsky (1969), a pag.193