entire at a glance; something within us must unify the various parts of the object, and perceive them simultaneously. If the brain is a sensitized plate on which the impression of the object is made, each atom contained in the cellule, or group of cellules, over which the impression is spread, would have its share of the impression; but must there not be some simple, indivisible principle pervading the brain substantially united to it, to explain the synthesis of these partial perceptions? Two objects are united in a judgment, and simultaneously perceived; the act of reasoning is still more complex. In fine, there is a supreme unity of the whole psychic life apparently pointing to the absolute unity and simplicity of its substratum, whereas the nervous system becomes increasingly complex.
That is the argument which finds most favour with scientifically-minded spiritualists. However, my professor at Louvain and several of the most distinguished Catholic philosophers rejected it, and through their criticism I came to see its weakness—its confusion of undividedness and indivisibility. A suggestion of Professor Huxley had always troubled me—the brain might not actually be a congeries of separate atoms. It is possible that Sir W. Thompson’s theory of atoms—that they are merely vortices in a continuous medium—may be correct; if so, the basis of the argument is destroyed. In any case, granting that consciousness may possibly be an efflorescence of nerve tissue, there seemed no great difficulty, when the nervous system is thoroughly studied, in ascribing the unity of conscious life to the unity of the nervous system.
Thus my criterion proved faulty, and I am unable to find any other grave reason for thinking that a spiritual and imperishable substance underlies our mental life. The apparent freedom of the will dissolves upon a careful study of the relation of motive to voluntary action. The power of reflection, from which springs the artistic faculty, does not present serious difficulty when we are dealing with a highly-developed nervous system, once the initial difficulty of consciousness is overcome. Much emphasis is often laid upon the fact that we are at all able to think about things spiritual; it is implied that matter, however elaborated, could not rise to such a level. But our ideas of the spiritual world, like our idea of the infinite, are only negative, in so far as they represent the immaterial; we abstract material characters and limitations from our ideas of objects, and they are spiritualized. And this power of abstraction, like the power of fusion or generalization, no more postulates the spirituality of the principle of thought than does the power of reflection.
Another argument that has become very popular is taken from the permanence or identity of consciousness at successive periods of life; it is here that science is supposed to give reluctant evidence in favour
