Schizophrenics frequently hallucinate, report delusions, behave in a strange way, react emotionally inadequately and think illogically or in a completely confused way. All these symptoms are pretty well understood within the framework of psychological theories of perception, emotion, thinking, or behavior. The fact that there is not one but many theories about these phenomena shows at least that it seems to be easy for patients as well as for clinicians to talk about the phenomena, i.e. conceptualize perceptual, thought-related, affective or behavioral problems or processes.