The view that the study of cognitive processes should consider those processes in abstraction from the environment in which the subject is placed. The most powerful motive for this suggestion is the comparison between cognitive processing and the following of a computer program. Any interpretation the elements of a computer program may have in the outside world (such as the fact that the symbol $ means a unit of currency) is irrelevant to the execution of the program. The doctrine may also be motivated by the idea that the psychological states of a person must supervene upon the states of the brain and on nothing else. Environment indeed affects the state of the brain, but then it is that state alone that creates and fixes the resultant psychology. This line of thought has been severely challenged, notably in the debates over wide and narrow content.
Philosophy dictionary. Academic. 2011.