Does Consciousness Depend on the Brain? (cont.)
By Chris Carter
According to Bergson the brain canalizes and limits the mind, restricting its focus of attention and excluding factors irrelevant for the organism’s survival and propagation. He assumed that memories have an extra-cerebral location, but that most are normally screened out for practical purposes, and in support of this, refers to near-death experiences in which the subjects’ entire life histories flashed before their eyes. The brain is therefore both “the organ of attention to life” and an obstacle to wider awareness. He speculates that if the brain is a limiting obstacle, filtering out forms of consciousness not necessary for the organism’s biological needs, then freedom from the body may well result in a more extended form of consciousness, which continues along its path of creative evolution.
In 1898 the American psychologist and philosopher William James delivered the Ingersoll Lecture. At the start of the lecture he first remarks that “Every one knows that arrests of brain development occasion imbecility, that blows on the head abolish memory or consciousness, and that brain-stimulants and poisons change the quality of our ideas.” He then makes the point that modern physiologists “have only shown this generally admitted fact of a dependence to be detailed and minute” in that “the various special forms of thinking are functions of special portions of the brain.”
James then explores the various possibilities for the exact type of functional dependence between the brain and consciousness. It is normally thought of as productive, in the sense that steam is produced as a function of the kettle. But this is not the only form of function that we find in nature: we also have at least two other forms of functional dependence: the permissive function, as found in the trigger of a crossbow; and the transmissive function, as of a lens or a prism. The lens or prism do not produce the light but merely transmit it in a different form. As James writes
Similarly, the keys of an organ have only a transmissive function. They open successively the various pipes and let the wind in the air-chest escape in various ways. The voices of the various pipes are constituted by the columns of air trembling as they emerge. But the air is not engendered in the organ. The organ proper, as distinguished from its air-chest, is only an apparatus for letting portions of it loose upon the world in these peculiarly limited shapes.
My thesis now is this, that, when we think of the law that thought is a function of the brain, we are not required to think of productive function only; we are entitled also to consider permissive or transmissive function. And this, the ordinary psychophysiologist leaves out of his account.
James then raises an objection to the transmissive theory of the body-mind relationship: yes, the transmission hypothesis may be a logical possibility, but isn’t it just unbridled speculation? Isn’t the production hypothesis simpler? Is it not more rigorously scientific to take the relationship between brain and mind to be one of production, not transmission?