There is an interesting parallel between Dick's emphasis here on a societally based definition of hallucinations -- as perceptions unshared by others -- and the insight offered by the eminent anthropologist Edward T. Hall in his Beyond Culture: "Perceptual aberrations are not restricted to psychoses but can also be situational in character, particularly in instances of great stress, excitation, or drug influences."* Instances, that is, in which, in Dick's words, "too much is emanating from the neurological apparatus of the organism."

* Edward T. Hall, Beyond Culture (New York: Anchor Books, 1976, 1981), p. 229.

In his 1965 essay "Schizophrenia and the Book of Changes" (also included), Dick sought to give the fearful and isolated perceptions of the schizophrenic an analytical coherence that might extend beyond the purely personal to a new viewpoint on human experience:

What distinguishes schizophrenic existence from that which the rest of us like to imagine we enjoy is the element of time. The schizophrenic is having it all now, whether he wants it or not; the whole can of film has descended on him, whereas we watch it progress frame by frame. So for him, causality does not exist. Instead, the a-causal connective principle which [quantum physicist] Wolfgang Pauli called Syncronicity is operating in all situations -- not merely as one factor at work, as with us. Like a person under LSD, the schizophrenic is engulfed in an endless now. It's not too much fun.

Dick described himself, in this essay, as "schizoid effective" -- a "pre-schizophrenic personality." This fearful dancing on the high wire of self-diagnostics is a recurrent element in Dick's essays and journals.