Physical theories can explain only physical phenomena. Consciousness arises from processes that are entirely explainable by physical theories. An explanation of physical structures and functions must be formulated in strictly physical terms. An explanation of consciousness must encompass more than an explanation of physical structures and functions.
Although consciousness seems to arise from physical processes, physical theories can explain only why physical systems have certain physical structures and how these systems perform various physical functions. Thus, no strictly physical theory can explain consciousness.
The conclusion of the argument follows logically if which one of the following is assumed?