1. There being, in Sensation, the concurrence of a series of physical or physiological facts with a mental fact, the name may be inadvertently employed to express the physical, as well {66} as the mental element, or at all events to include the physical part as well as the mental. The change made on the retina by light, and the nervous influences traversing the brain, may very readily be considered as entering into the phenomenon of sensation. This, however, is an impropriety. The proper use of "Sensation" is to signify the mental fact, to the exclusion of all the physical processes essential to its production. 2. In ordinary Sensation, as in looking round a room, there is a double consciousness,--objective and subjective. In the objective consciousness, we are affected with the qualities named magnitude, distance, form, colour, &c.; these are called object properties, properties of the external and extended universe. In the subject consciousness, we are alive to states of pleasure or of pain, which may go along with the other. We do not usually exist in both modes at one instant; we pass out of one into the other. Now the word Sensation covers both, although, to the object consciousness, "Perception" is more strictly applicable; and in contrast to Perception, Sensation would mean the subjective consciousness, the moments when we relapse from the object attitude and become subjective or self-conscious, or alive to pleasure and pain. When the mind is in the object phase, it is neutral or indifferent as respects enjoyment. 3. In Sensation, a distinction may be drawn between the present effect upon the mind, or the impression that would arise if the outward agent had operated for the first time, and the total of the past impressions of the same agent, which by its repetition are recalled to fuse with the present effect. The present view of the moon reinstates the sum total of the previous views held by memory, and is not what we should experience if we saw the moon for the first time. Now, if the recall of the previous impressions, or of the joint and iterated idea, be considered an addition made by the Intellect, being dependent on the retentive power of the mind, Sensation, as opposed to Intellect, would mean the force of the present impression and nothing more; or the difference between the {67} vividness of reality, and the inferior vividness of recollection. What we can retain when we shut our eyes would represent the force of our intelligence; the additional intensity when we resume our gaze, would represent the power of sensation or the actual experience.