Abstract
THE doctrine that there is a distinct organ for the realisation of Sensations only, apart from that for Perception, has been very generally taught, and has been insisted on by no one more strongly than by Dr. Carpenter in his otherwise most able and suggestive expositions of nervous physiology. He says:* “The general rule of action appears to be that the impressions made by external objects upon the afferent nerves, when transmitted to the spinal cord, ascend towards the cerebrum without exciting any reflex movements in their course. When such an impression arrives at the sensorium,† it excites the consciousness of the individual, and thus gives rise to a sensation and the change thus induced being further propagated from the sensory ganglia to the cerebrum, gives occasion to the formation of an idea” And that Dr. Carpenter here means by the word ‘idea’ what we have previously spoken of as that complex intellectualised sensation generally called a ‘perception’ seems obvious from the following passage occurring on another page, where the same author says: “It is further important to keep in mind the distinction between the sensations themselves and the ideas which are the immediate results of those sensations when they are perceived by the mind. The ideas relate to the cause of the sensation or the object by which the impression is made”(p. 711). But since, in Dr. Carpenter's view, the sensory ganglia constitute the sensorium, in which impressions become conscious sensations; and because he naturally thinks it very improbable that there are two distinct organs of consciousness, he is compelled to adopt the hypothesis that the superficial grey matter of the cerebral hemispheres, in which intellectual operations are principally carried on, is not itself endowed with the function of consciousness. Thus he assumes—as the most probable inference to be drawn from various kinds of evidence—“that the sensory ganglia constitute the seat of consciousness not merely for impressions on the organs of sense, but also for changes in the cortical substance of the cerebrum; so that until the latter have reacted downwards upon the sensorium we have no consciousness either of the formation of ideas or of any intellectual processes of which these may be the subject.”‡ And, although we are quite-unable to agree with the conclusions themselves as to the absence of consciousness in connection with the activity of the cerebral hemispheres, and as to its presence as a functional attribute of the sensory ganglia alone, still it is sufficiently interesting, in a philosophical point of view, to find Dr. Carpenter declaring so confidently in favour of a distinct organ of consciousness, even altogether separate from those parts of the cerebral hemispheres in which what we have called § potential knowledge is produced—meaning by this term what is called knowledge, so far as it can exist minus the attribute of consciousness. The elaboration of this potential knowledge is, in fact, a process the possibility of which has been ably discussed by Dr. Carpenter in the section in which he speaks of “unconscious cerebration.”
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BASTIAN, H. Sensation and Perception: II. Nature 1, 309–311 (1870). https://doi.org/10.1038/001309a0
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DOI: https://doi.org/10.1038/001309a0