might not know, for we might lose the organ of conscious memory on the way down to the beginning of things, a path up which, in a very real sense, every human being has come in person.
If the question whether living things are conscious can be answered positively in only one case, and with great probability for the rest of our fellow-men and some few of the higher animals, but not at all for the lower forms or the early stages in the development of the higher, practical needs force us to act on our ignorance, and to deal with these matters as they appear to be and not as they might be, although we cannot dogmatize and must grant the reasonableness of William Keith Brooks when he says: “As for myself, I try to treat all living things, plants as well as animals, as if they may have some small part of a sensitive life like my own, although I know nothing about the presence or absence of sense in most living things; and am no more prepared to make a negative than a positive statement.” I do not know whom we should consider the greater fool, the man who went abroad declaiming about the unconsciousness of the oak, or him whom we should discover trying to teach an oak the Greek alphabet.
This is where we stand on the question of consciousness, but the question of the vital X is even more difficult, for we have no experience of it comparable to our first-hand knowledge of consciousness. I have not the faintest idea what living is like except as I know this consciously, for unconscious knowledge or experience is altogether outside my line of business. Hence if there is a vital X in ourselves other than consciousness, I know nothing about it, and if I can not even be sure of consciousness in most living things, I certainly can have no good reason for assigning to them an X of which I not only know nothing, but have no present means of knowledge.
The progress which scientific explanation has made in our own lives, however, should warn us that no one can tell what will come next. It is by no means inconceivable that some day we shall be so familiar with the physical-chemical changes which to-day we know as feelings and thoughts, that we shall be able to infer consciousness from these reactions with the same certainty with which we infer now that a match lit under the nose of a fellow-man has hurt him in much the same way as it would have hurt us.
To my way of looking at things, there are only two possibilities with respect to the vital X, and when the day comes on which the inference of consciousness from its physical symbols shall seem safe and just to the man of science, these possibilities will stand out even more sharply than they do in the present scientific dawn, for the man of the future, equipped with the knowledge with which we have endowed him, will be able to decide whether the X in question is a variety of extra-personal consciousness or a variety of nonsense.