It is interesting to note, however, that Dr. Frederick Peterson, of Columbia University, New York, has lately put forward the theory that there is, or may be, a seat of consciousness, after all! In a striking article in the Journal of Abnormal Psychology (vol. iii. No. 5), he says:—
"I will say at once that the 'seat' of that power which produces the manifestations of consciousness is in the basal ganglia (probably the corpora striata), and that consciousness is a peculiar summation of energy at that point, capable of being directed, like the rays of a searchlight, into this or that portion of the brain."
Dr. Peterson then goes on to give some facts which seem to him to support this view. Among these are the phenomena of sleep (the reasons being too long to detail here); the fact that, although every individual brain is stored full of experiences, only a small area is illuminated by consciousness at any one moment; and the phenomena of epilepsy—concerning which Dr. Peterson speaks in the following terms:
"The one disorder which has led me to think much of this subject is epilepsy, in which disease, loss of consciousness is the most extraordinary and often the only symptom. I allude chiefly to such remarkable conditions as the tic de salaam and the other forms of petit mal, in which the patient drops suddenly to the floor with loss of consciousness, and quite as suddenly rises again in full possession of his faculties. I have watched such cases for hours, and always with increasing marvel. The loss of consciousness is complete, and often lasts but a fraction of a second. How account for such phenomenon! If consciousness were a diffused attribute of the whole brain, what spasm of blood-vessels or other physical process familiar to us could act and be adjusted with such speed? If, however, the 'seat' of consciousness be limited to some very small portion of the brain, some physical process such as is suggested could easily account for the instantaneous loss and regaining of consciousness."
Other facts in support of this theory are given, and the statement of Dr. C. L. Dana that, in poisoning by illuminating gas, the chief symptom is loss of consciousness, and the only lesion discovered is softening of the corpora striata; then the following:
"Assuming now that it were proved that the power which creates consciousness has some definite seat, and that it is a summation of energies physiologically varying in sleep and waking, which may be directed to any part of our store of experiences for purposes of illumination, what portion of the brain is so constructed as to be in apparently intimate connection with every other? The corpora striata!... There is no portion of the brain we know so little of.... Here we have a portion of the brain which must be of enormous significance, otherwise it would not be always present, from the fish up to man."
It will be seen that Dr. Peterson is here opposed to the doctrine maintained by both Lotze[5] and MacDougall,[6] who both maintained that: "There are a number of separate points in the brain which form so many 'seats' of the soul. Each of these would be of equal value with the rest; at each of them the soul would be present with equal completeness." But whether there be one or several "seats" of consciousness, it is obvious that there must be contact of some sort, at one or several points (granting the correctness of the theory that spirit acts upon matter at all), and the question is: How may this action be supposed to take place?
In discussing this question in a former book[7] I said:
"It is more than probable, it seems to me, that there exists some sort of etheric medium between mind and even organic nervous tissue, upon which the mind must act first of all. Thus, we should have the chain of connection: mind, vital or etheric medium, nervous tissue, muscle, bone. So mind acts upon matter; and it will be seen that there is an increasing density of structure, and that just in proportion to this density is mind incapable of affecting matter directly. We must, it seems to me, always postulate some sort of etheric medium through which mind acts, in order to affect and move matter—organic or inorganic. And without this vital intermediary there can be no action, and consequently no manifestation."
Now, it would appear rational to suppose that some action of this sort takes place when mind acts upon, or influences, matter. Air is invisible, and practically imperceptible to our senses—when stationary. But set into motion, a current of air will close a door with a bang—will have the effect of definitely moving a heavy mass of inanimate matter, in the manner indicated. It may be that in somewhat the same way mind affects brain. Mind may reside in a sort of etheric vehicle, and be more or less stable or stationary, save at the times when volition or intense, active conscious operations are in progress—when, in short, effort is exerted. At such times, it is surely conceivable that what was static becomes dynamic; something is set into motion which in turn brings into activity some more "physical" energy, and so on, until sufficient material momentum has been gained to affect that most unstable and mobile substance, nervous tissue. It is certainly quite conceivable that certain nervous centres in the brain (which centres, we cannot say) might be set into actual operation by some such process; or at least that the impulse or energy supplied in this manner might be sufficient to release the nervous energy stored in the cell, much as the trigger of a rifle would, when pressed, release the energy contained within the cartridge. Such "hair trigger" action has been postulated by both William James and Bergson, and is certainly in line with modern speculations in this direction. There are also certain analogies to be drawn from physical science to guide us here.