In this paper, we propose a reasoning model aimed at helping to decide on the virtual status of a given situation, from a human point of view rather than from a technological one. We first describe how a human and his environment interact. The notion of “reality” will be seen through this description. Then, we propose a set of possible “cognitive deviations” of reality leading to situations of virtual reality. This model provides three major benefits to the field of Virtual Reality: first, a global definition and a systematic mean of categorizing related situations; secondly, the ability to discuss on the virtual status of real situations and not only synthetic, computer generated ones; thirdly, a demonstration on how the field of Tele-Operation is heavily related to virtual reality concepts, and some perspectives on future tele-operation intelligent user interfaces.