_Involves a twofold Element._--Looking more closely at the character of this faculty, we find it to involve a twofold element, which we cannot better indicate than by the terms _subjective_ and _objective_. There is, in the first place, the knowledge or consciousness of our own sentient organism as affected, and there is also the knowledge of something external to, and independent of the mind itself, or the me, as the producing cause of this affection of the organism. We know, by one and the same act, ourselves as affected, and the existence and presence of an external something affecting us. This presupposes, of course, the distinct independent existence of the _me_ and the _not-me_--of ourselves as thinking and sentient beings, and of objects external to ourselves, and material,--a distinction which lies at the foundation of all sense-perception. All perception by the senses involves, and presupposes, the existence of a sentient being capable of perceiving, and of an object capable of being perceived. It supposes, also, such a relation between the two, that the former is affected by the presence of the latter. From this results perception in its twofold aspect, or the knowledge, on the part of the sentient mind, at once of itself as affected, and of the object as affecting it. According as one or the other of these elements is more directly the object of attention, so the subjective and the objective character predominate in the act of perception. If the former, then we think chiefly of the me as affected, and are scarcely conscious of the external object as the source or the producing cause; if the latter, the reverse is true. § II--ANALYSIS OF THE PERCEPTIVE PROCESS. _Simple Sensation._--The nature of the presentative power may be better understood by observing closely the different steps of the process. As we come into contact with the external world, the first thing of which we are conscious, the first step in the process of cognition, is doubtless simple sensation. Something touches me, my bodily organism is thereby affected, and I am conscious, at once, of a certain feeling or sensation. I do not know as yet what has produced the sensation, or whether any thing produced it. I do not as yet recognize it as the result of an affection of the bodily organism, or even as pertaining to that organism in distinction from the spiritual principle. I am conscious only of a certain feeling. This is simple _sensation_--a purely subjective process. _Recognition of it as such._--We do not, however, stop here. The mind is at once aroused by the occurrence of the phenomenon supposed, the attention is directed to it. I cognize it as sensation, as feeling. If it be not the first instance of the kind in my experience, I distinguish it from other sensations which I have felt.