The empiricist approach has assumed that the structure of the acquisition device is limited to certain elementary "peripheral processing mechanisms" - for example, in recent versions, an innate "quality space" with an innate "distance" defined on it [...] a set of primitive unconditioned reflexes [...] or, in the case of language, the set of all "aurally distinguishable components" of the full "auditory impression" [...] Beyond this, it assumes that the device has certain analytical data processing mechanisms or inductive principles of a very elementary sort, for example, certain principles of association, weak principles of "generalization" involving gradients along the dimensions of the given quality space, or, in our case, taxonomic principles of segmentation and classification such as those that have been developed with some care in modern linguistics […].
- Chomsky (1969), a pag.47

In the particular case of language acquisition, the empiricist approach begins its investigation with the stipulation that certain arbitrarily selected data-processing mechanisms (e.g., principles of association, taxonomic procedures) are the only ones available to the language-acquisition device. It then investigates the application of this procedures to data, without, howewer, attempting to show that the result of this application corresponds to grammars that can be shown, independently, to be descriptively adequate.
- Chomsky (1969), a pag.207