 Adherents of the direct realist model are thus criticized by those of the causation model for admitting improper, non-existent apprehended objects (namely, the concept and the hallucinated object), and for blurring the difference between the respective modes of operation of non-conceptual and conceptual cognitions. In return, the causation model is criticized in that it does not enable direct access to real objects; those can, at best, be inferred.