in psychiatry, as in other fields of medicine, the beginning of clinical science is the collection of observable data and the study of their interrelational patterns. The second step is methodical observation, utilizing specific means to extend and focus the scope of the observation in the experiment. Further development brings out the neurophysiological and neurochemical basis of psychiatry. Nevertheless, none of this information is necessarily etiological, for, even if the pathomechanism is revealed, the pathogenesis may remain hidden.