A more significant distinction between associa tion and thought is that between the characters of the connections involved. Association-connections arc random; there is no internal logical consis tency. An unknown dog may suggest a familiar eat, and the latter may by some queer freak of association call up the word catastrophe, and the image of some horrible experience. In this mere association-process each step taken is ex plicable by the familiar laws of association, but there is no logical coherence between the first step and the lost. The unknown dog and the fatal railway wreck (To not belong together. On the other hand, in thought-processes the whole series from beginning to end is controlled by some central interest. The final stage of the process is as closely connected with the initial stage as with the intervening stages. All the ideas tra versed in the movement form a consistent whole. Such a thought-process completely domi nated by some single interest is not frequent. Generally our thoughts are only loosely con nected; we break the continuity of the train and then reconnect the broken ends. Sometimes the breaks are rare; sometimes they are annoy ingly frequent. There is no hard and fast line of difference between association and thought. Very little of our thinking is absolutely direct and altogether pertinent. The difference between asso ciation and thought is one of degree. Association is loose-jointed and random thinking; thought is compact and coherent association. If this is so, we may say that there is no experience that we can conceive from which thought is absent; and that so far from its being true that the less thought there is, the more reality, it is rather the reverse which is true. The more coherence and consistency there is between all the parts of our sense-experience, the more sure we are of their reality. The better our thinking, the nearer we are to reality, provided of course we have some sense-content in our thinking. Mere think ing would be of no more value, if it really could exist, than mere sense. We never get at such reality as we know without thought upon sense data. In this coliperation of thought and sense toward the production of knowledge of reality, it cannot be said that sense is nearer to reality than thought. Neither is nearer than the other any more than the father is nearer to the child by procreation than the mother, or rice versa.
Only one more objection to the validity of knowledge can be considered here. After all, it. will be urged, we have knowledge of reality only by means of ideas or sensations, which are them selves not the reality. Hence there is always the possibility that our means are defective inasmuch as we can never get directly at the ohjeet known, in order to compare it with our sensations and ideas. We have to assume the validity of knowl edge, it is conceded; but we must, it is urged, realize that it is, when all is said, a gigantic assumption, or simply a working hypothesis. We can never know that we really know, although wo must always take that knowledge for granted. This objection, although very popular at present, is as futile as all the others we have examined, for if it is a valid objection, it must be backed by reasons. These reasons can be stated in the words of Prof. Karl Pearson: "How close then can we actually get to this supposed world out side ourselves? Just as near as but no nearer than the brain terminals of the sensory nerves. We are like the clerk in the central telephone ex change who cannot g,et nearer to his customers than his end of the telephone wires. We are in deed worse off than the clerk, for to carry out the analogy properly we must suppose him never to have been outside the telephone exchange, never to hare seen a customer, or any one like a cus tomer—in short, never, except through the tele phone wire, to hare come in contact with the oniside vnircrse. . . Very much in the posi tion of such a telephone clerk is the conscious ego of each one of us seated at the brain ter minals of the sensory nerves. Not a step nearer than these terminals can the ego get to the 'outer world,' and what in and for themselves are the subscribers to its nerve exchange it has no means of ascertaining. . . . The sounds from tele phone and phonograph correspond to immediate mid stored sense-impressions. These sense-im pressions we project as it were term the real world outside ourselves. Ilot the things-in-themsel•es which the sense-impressions symbolize, the 'reality,' as the metaphysicians wish to call it, at the other end of the nerve, remains unknown and unknowable." The objection thus admirably stated may be called the psycho-physical argument against knowledge of reality. The reply to it can best be introduced with a question: How do we know that the ego is seated at the brain terminals of the sensory nerves? How, indeed, do we know that there are any sensory nerves at all? If all that we know are sensations, considered as merely sub jective and psychical, what right have we to talk about brain terminals? A very little reflec tion will convince any one that without any knowledge of the external world one would never come to think of his own experiences as internal and subjective. We first conic to know the ob
jects about its, among others the bodies of our neighbors. By dissection of some of these bodies we come to know that there is a brain in the human head and that there arc nerves running from innumerable points in the periphery of the human body back to the brain. By observation and experimentation we come to know that cer tain stimuli applied to the ends of certain nerves are followed, or accompanied, by conscious pro cesses. Because in the ease of human subjects any sundering of the nerve is followed by cessa tion of the specific conscious process that ordi narily is coordinated with the stimulation of the nerve, we reason that the conscious process is only indirectly coordinated with the action of the nerve, and directly with some sort of disturbance in the brain. The only justifiable meaning then of the expression, "the conscious ego of each of us seated at the brain terminals of the sensory nerves," is 'the unitary complex of conscious pro cesses that arise when the brain is stimulated.' These processes are not seated at the terminals of the sensory nerves and subsequently ejected into the space outside the body. At least no scientific observer has ever found, say, a color sensation seated at the terminal of his optic nerve and subsequently extruded into outer space. All this talk about. the 'seat' of conscious pro cesses is the sheerest mythology, if anything else is meant than that very careful research based on known facts of external stimulus and nerve-dis turbance has led scientists to locate within the brain the physiological processes with which the psychical processes are correlated. The psychical processes are not experimentally located there; and any one who interprets the findings of psycho-physics into a location of psychical pro cesses at the terminals of sensory nerves is the dupe of a simple and transparent metaphor. But it will he said that if the brain is the last object disturbed before consciousness arises. then con sciousness must he somewhere in the neighbor hood of the brain. This contention is obviously based on the very questionable principle that no object can act at a distance. Even in mere physical action it is by no means certain that the principle is true. A physical body attracts another physical body at vast distances, and it is by no means certain that this action is medi ated by some intervening ether. But even if it he coliceded that the principle is true in mechanical physics, \ vhat right have we to assume that it is also true in psycho-physics? As psychic pro c•sses are facts, it is necessary to observe them impartially, i.e. without any prepossessions. in order to tied out what principles govern their action. It is very queer science that assumes. to begin with, that they must be subject to a prin ciple that possibly obtains in the merely physical world. Now, observation of the fact of visual perception, for example, does not confirm the sup position that the color-sensations are at first 'seated' at the terminals of the optic nerves, and that afterwards we 'project' them 'as it were, outwards.' So far as any actual visual experi ence can he interrogated, the answer always is that color-sensations are always located in objects before the eves. If the ease is different in in fants, we cannot ascertain that fact directly. but must infer it, and the only principle that would warrant the inference is that doubtful one just discussed, viz. that no object can net at a (Hs lance. It is obvious therefore that the session of the ego at the terminals of the sensory nerves must not be used as a proof of the fact that we cannot know anything of the outer world; that session is itself a very dubious inference from known facts of the outer world, viz. anatomi cal and physiological facts which we come to know in exactly the same way in which we conic to know any other facts of that same outer world. We use our senses; and we thoughtfully compare the results we get by their use, and after criti cism come to some conclusion as to the facts. In fine, this whole doctrine of the subjectivity of knowledge is itself only a suicidal inference from known objective facts. It is suicidal because if it were true the only reasons that can be urged for its truth, viz. certain psycho-physical facts, would be deprived of their validity, inasmuch as these reasons can claim validity only on the ground that they are known facts of the objective world. De•e, as heretofore, we see that knowledge cannot be impugned without presupposing In summary of this criticism of agnostic views. it may be said that no known fact can lie consist ently and logically used to demonstrate the im possibility of knowledge. Knowledge is a fact as indubitable. as real. as inevitable as any fact of sensation, and the validity of any knowledge cannot he assailed except from the vantage ground of better knowledge.