To the mind of any individual man the real existence (as also the real essence) of any being whatsoever, not excepting his own, can be known only through its ideal presence in his mind, through the concept or percept whereby it becomes for him a “known object,” an _objectum cognitum_. But this actual presence of known being to the knowing mind must not be confounded with the real existence of such being (4). Real being does not get its real existence in our minds or from our minds. Our cognition does not produce, but only discovers, actually existing reality. The latter, by acting on the mind, engenders therein the cognition of itself. Now all our knowledge comes through the senses; and sense cognition is excited in us by the direct action of material or phenomenal being on our sense faculties. But through sense cognition the mind is able to attain to a knowledge both of the possibility and of the actual existence of suprasensible or spiritual realities. Hence we cannot describe existence as the power which material realities have to excite in us a knowledge of themselves. Their existence is prior to this activity: _prius est esse quam agere_. Nor can we limit existence to material realities; for if there are spiritual realities these too have existence, though this existence can be discerned only by intellect, and not by sense. 13. ESSENCE.—In any existing thing we can distinguish _what the thing is_, its _essence_, from its actual _existence_. If we abstract from the actual existence of a thing, not considering whether it actually exists or not, and fix our attention merely on _what the thing is_, we are thinking of its _real essence_. If we positively exclude the notion of actual existence from our concept of the essence, and think of the latter as not actually existing, we are considering it formally as a _possible essence_. There is no being, even the Necessary Being, whose essence we cannot think of in the former way, _i.e._ _without including_ in our concept the notion of actual existence; but we cannot without error _positively exclude_ the notion of actual existence from our concept of the Necessary Being, or think of the latter as a _merely possible_ essence.