I would characterize such artifacts [terciary], abstracted from their direct representational function, as ‘tertiary’ artifacts, and suggest that they constitute a domain in which there is a free construction in the imagination of rules and operations different from those adopted for ordinary ‘this-worldly’ praxis. Such possible worlds may indeed reflect the limits of perceptual praxis in a given ‘actual world’ – i.e. a world in which direct outward and necessary productive praxis takes place, in accordance with rules, and ontologies evolved through this praxis. That is to say, just as in dreams our imagery is derived from our ordinary perception, but transcends or violates the usual constraints, so too in imaginative praxis, the perceptual modes are derived from and related to a given historical mode of perception, but are no longer bound to it.
Wartofsky, M. W. (1979). Perception, representation, and the forms of action: Towards an historical epistemology. En A portrait of twenty-five years (pp. 215-237). Springer: Dordrecht.