COGITATIO. ¦ ¦ ACTIO ¦ PASSIO ¦ ¦ ¦ (Mens sola; clarae et distinctae ¦ (Mens unita cum corpore; ideae.) ¦ confusae ideae.) ¦ VOLITIO: ¦ 6. Voluntas. 3b. Commotiones ¦ 3a. Affectus. 2. Appetitus naturales. ¦ intellectuales¦ ¦ ¦ ¦ ¦ \ / ¦ ¦ --------v------- Judicium. ¦ Sensus interni ---------------------------------+----------------------------------- ¦ ¦ PERCEPTIO: 4. Imaginatio ------^------ / \ 5. Intellectus 4b. Phantasia. ¦ 4a. Memoria. 1. Sensus externi. Accordingly six grades of mental function are to be distinguished: (1) The external senses. (2) The natural appetites. (3) The passions (which, together with the natural appetites, constitute the internal senses, and from which the mental emotions produced by the intellect are quite distinct). (4) The imagination with its two divisions, passive memory and active phantasy. (5) The intellect or reason. (6) The will. These various stages or faculties are, however, not distinct parts of the soul, as in the old psychology, in opposition to which Descartes emphatically defends the _unity of the soul_. It is one and the same psychical power that exercises the higher and the lower, the rational and the sensuous, the practical and the theoretical activities.