The Subject of Consciousness
© C.O. Evans

Chapter 4

Unprojected Consciousness - 4.3.8
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3. Unprojected Consciousness and Executive Attention

[8] Since Ribot has referred to the physical signs of attention - respiratory modifications, frowning, and so forth - it will avoid confusion if at this point something is said about the physiological aspects of attention.

The study of attention from the physiological point of view has revealed other bodily changes besides the changes in muscular activity with which I have been dealing. It is claimed, for instance, that during attention the blood supply to the brain increases. It has also been suggested that the mysterious alpha-waves in the brain

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have a connection with attention. 94 Putative changes of this sort must be distinguished from the changes that take place in muscle activity, because the latter sort of changes are subject to voluntary control, while the former are not (except indirectly). Those bodily changes, the occurrence of which are not directly subject to the control of our will, I shall call processes. By contrast the bodily changes that are subject to our will, I shall call activities. It must be appreciated that bodily changes do not need to be willed in order for them to be activities. They are activities in virtue of the fact that they can be willed.

A minor difficulty exists in that it can legitimately be claimed that the ability to contract muscles at will is a sophisticated performance, and that what we normally will are movements of our bodies, and not contractions of our muscles. For instance I will that my arm should go up: I do not will the contraction of the muscles which must occur if my arm is to go up. I, in all probability, do not even know what these muscles are. That is to say, I know how to move parts of my body, but I do not necessarily know how to move the relevant muscles. I know how to move my eyes about, but I need know nothing of the existence of the six muscles by means of which the eye movements are effected. This point can be admitted without further ado. 95 We need only remember that when muscle activity is said to be voluntary, what is meant is that certain movements can be performed at will only when the relevant striated muscles are brought into play. Those muscular changes that cannot be innervated by willing are to be excluded from the class of voluntary muscular activities. The muscles for increasing the tension of the tympanum in the ear belong to this latter category. The 'smooth' muscles of the body, and the cardiac muscle are the main types of muscle over which we cannot (normally) exert direct control.

What I call bodily processes are such things as the beat of the heart, digestive action, etc. These processes are governed by the autonomic nervous system, and they go on whether we are conscious of them or not, or indeed whether we are conscious or not.

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Although it is possible to exercise some degree of voluntary control over some of these processes, this can only be done indirectly. I can, for instance, make my heart beat faster, but I cannot do it by simply willing my heart to beat faster. I have to use my knowledge that exertion makes the heart beat faster, and first exert myself by making a movement I can will. My heart will then beat faster. The difference between the way I raise my arm on willing it, and the way I make my heart beat faster, is the measure of the difference between my control over my bodily activities, and my control over bodily processes. What is of philosophical interest is the connection between bodily activity and attention, and this is of interest only because we seem to have discovered a conceptual link between the two. The connection between attention and bodily process, on the other hand, is contingent. We would not be obliged to alter our concept of attention if it were found that there was no increase of blood to the brain during attention, or that alpha-waves had nothing to do with it either.

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Footnotes

94. The EEG record of the electrical activity of the brain reveals a characteristic alpha-rhythm while the subject is not paying attention to anything, but as soon as he attends the alpha-wave disappears. See, W. G. Walter, The Living Brain (Pelican, 1963).
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95. For an argument to the effect that we will certain muscular movements primarily and not our limbs, see, C A. Campbell 'Self-Activity and Its Modes', Contemporary British Philosophy, ed. H. D. Lewis (London, 1956).
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