simple, naive habits of thought and speech, which were those of a man of the world rather than of a scholar, were quite incompatible with the adoption and consistent use of a finely discriminated terminology; he is very free with sive, and not very careful with the expressions actio, passio, perceptio, affectio, volitio.  First he equates activity and willing, for the will springs exclusively from the soul—­it is only in willing that the latter is entirely independent; while, on the other hand, passivity is made equivalent to representation and cognition, for the soul does not create its ideas, but receives them,—­sensuous impressions coming to her quite evidently from the body.  These equations, “actio—­the practical, passio = the theoretical function,” are soon limited and modified, however.  The natural appetites and affections are forms of volition, it is true, but not free products of the mind, for they take their origin in its connection with the body.  Further, not all perceptions have a sensuous origin; when the soul makes free use of its ideas in imagination, especially when in pure thought it dwells on itself, when without the interference of the imagination it gazes on its rational nature, it is by no means passive merely.  Every act of the will, again, is accompanied by the consciousness of volition.  The volitio is an activity, the cogitatio volitionis a passivity; the soul affects itself, is passively affected through its own activity, is at the same instant both active and passive.

[Footnote 1:  For details cf. the able monograph of Dr. Anton Koch, 1881.]

Thus not every volition, e.g. sensuous desire, is action nor all perception, e.g. that of the pure intellect, passion.  Finally, certain psychical phenomena fall indifferently under the head of perception or of volition, e.g., pain, which is both an indistinct idea of something and an impulse to shun it.  In accordance with these emendations, and omitting certain disturbing points of secondary importance, the matter may be thus represented: 

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