42. The case is the same with love and wisdom, the only difference being that the substances and forms which constitute love and wisdom are not visible to the eyes as the organs of the external senses are. But still, no one can deny that substances and forms constitute those elements of wisdom and love that are called thoughts, perceptions and affections, and that these are not aerial entities flying about or flowing out of nothing, or things abstracted from real and actual substance and form which are the subjects of which they are predicated. For the brain has in it countless substances and forms which are the seat of every interior sense connected with the intellect and will. All affections, perceptions and thoughts in those substances and forms are not exhalations from them, but are actually and really subjects which emit nothing from them, but simply undergo changes of state in accordance with the incoming stimuli that affect them, as may be seen from the observations above regarding the outward senses. (Regarding the incoming stimuli that affect them, more will be said below.)