Healy believes this oversimplified neurotransmitter "language" supported psychiatry’s transition from dimensional to categorical thinking. Temperament, personality, psychodynamics, culture, social circumstances, and personal misfortune as dimensions of the human experience of depression became relatively unimportant to neurotransmitter psychiatry, which increasingly thought in axis I neo-Kraepelinian categories. At the center of neo-Kraepelinism, Healy places Gerald Klerman, Eli Robins, Donald Klein, Robert Spitzer, and others dubbed an invisible college that produced the DSM-III revolution. Robert Michels is credited with the best critical line about the making of DSM-III: diagnosis in medicine aims "to carve nature at its joints," as one might disarticulate the Thanksgiving turkey, but the invisible college decided to carve by the feathers (p. 234).