For example, in a biological context, an image of a rose is seen as a composition of petals, sepals, leaves and stems, whereas in an artistic context the images is seen as a composition of colour patches, shadings and edges.

Zenon Pylyshyn (1981).

Cognitively penetrable: a mental phenomenon is cognitively penetrable if it can be accessed and altered by other thought processes. For example a belief that the cat is on the mat is cognitively penetrable, because it can be altered by further information that the cat is actually a dummy.

According to Pylyshyn, those phenomenon that are cognitively penetrable are generally explained in terms of symbolic rule governed processes and operate on the more basic, cognitively impenetrable components.

Cognitively impenetrable: a mental phenomenon is cognitively impenetrable it cannot be accessed or altered by other thought processes. For example, a person’s perception of red is cognitively impenetrable, because it can’t be changed to a perception of green.

According to Pylyshyn, cognitively impenetrable phenomena are primitive explanatory concepts, because they remain basics throughout changes of context.