large room full of people who are talking all around you in many independent groups. A mass of sound comes to your ear. Consciousness interferes to make you pick out one or another of the series of sounds, an act which is indeed made possible by the natural analytic tendency of the human auditory sense, but which does not take place without a noticeable effort of attention. When you are learning a foreign lan¬ guage, and are for a while much among those who speak it, there comes a time when your ear and mind are well enough trained to follow and under¬ stand ordinary speakers with only a little effort of attention; but yet, at this stage, you are able, by simply withdrawing your attention a mere trifle, to let very common phrases run through your sense without your understanding them one whit. You can thus, by a slight change of attention, convert the foreign language from a jargon into a familiar speech, and back again into a jargon, just as, in the fixed visual field, you can make yourself see an ob¬ ject pretty plainly, or lose it altogether, by ceasing to give attention.
All these instances, which could be indefinitely multiplied, prove, first, that what we call attention modifies the knowledge that we at any moment get; and secondly, that this modification, through atten¬ tion, may take place without any change in the im¬ pressions that at any moment come from without. The first stage in getting knowledge from bare senseimpressions is therefore the modification of sense by attention — a process belonging wholly to the sub¬ jective side; i. e. to our own minds.
But what is attention? and how. does it modify sensation? Apparently, attention in the previous instances has been merely a power to increase or to diminish the intensity of impressions. But is this all that attention does? No: there are many cases in which attention directly affects the quality, at least of our complex impressions. This direct modi¬ fication is commonly attended by some alteration of our emotional state. It is a familiar fact, that in listening to a series of regular and even beats, such as the strokes of an engine, or of a pendulum, or the ticking of a watch, we have a tendency to modify the impressions by introducing into their series the more elaborate regularity of rhythm. In paying at¬ tention to them, we increase, at our pleasure, the in¬ tensity of every third or fourth beat as heard, and so make a rhythm, or series of measures, out of the actually monotonous impressions. Now attention, which here first acts by modifying the intensity of impressions, soon produces the effect of qualitatively modifying our total impression of the whole series.
If I have taken the fancy to listen to the even strokes in quadruple time, intensifying by my own act every fourth stroke, the character of the series is changed for me. The impressions are less monoto¬ nous, and they arouse new associations. They seem to be caused by some force that rhythmically in¬ creases and decreases. Perhaps a melody, or some phrase of a few words, arises in my mind, and per¬ sists in associating itself with the strokes. Probably some vague feeling, as of rhythmic motion through the air, or of pleasure or of displeasure in the pres¬ ence of some rhythmically moving living being, is awakened. Qualitatively, my consciousness is thus altered through my attention. I seem to be experiencing something that, as an objective reality, I do not experience. More striking becomes this quali¬ tative alteration of experience through attention, in case you bring two watches of different beat, or a watch and a clock, and listen to both at once at the distance of a few inches, first, perhaps, stopping one ear to avoid confusion. Here, by attention, you make or try to make a compound rhythm, and this effort alters a good deal the total impres¬ sion that you derive from the sound. If the two series are such that a simple small multiple of the interval of one gives you a simple small multiple of the other’s interval, you can combine the two series into one rhythm, and then there is an immediate impression as if the two series were really but the complex ticking of one source of sound. But if the series will not agree, there is an odd sense of some¬ thing wrong, a disappointed effort to combine, joined, perhaps, with a tendency to hasten one of the series, so as to make it agree with the other. An¬ other case where attention alters the quality of total impressions, and not merely the intensity of any part, appears in certain psychological laboratory ex¬ periments, described by W undt in his “ Physiologische Psychologie.” Here, for the sake of deter¬ mining the actual time taken by an act of attention, an observer is to make an electric signal as soon as he becomes conscious of a certain impression, while the impression itself is produced by an assistant at a time exactly determined. The source of the impres¬ sion is the ringing of a bell, the flash of an electric spark, or something of the kind agreed upon at the THE WORLD OE THE POSTULATES outset. To distinguish from one another the various causes of the delay of the signal, the conditions of experiment are variously modified. In one set of experiments, the observer does not know beforehand whether he is to experience a flash of light, or a sound, or some sensation of touch, nor how intense the sensation will be, nor when it will come; but he knows that he is to be on the lookout for one of the three kinds of sensation. He waits, with attention all aroused. In this case, it always takes him longei to signal than if he knew beforehand the kind and O the strength of the coming sensation. Moreover, his attention now makes him uneasy; the coming sen¬ sation is expected, with signs of excitement, and is often received with a start. Here the feeling of ef¬ fort that accompanies attention affects by its strength the character of the impression received. Moreover, in many of these experiments there appear phenom¬ ena that show that attention alters our perception of time, not merely as to length, but also as to se¬ quence; so that under circumstances, an impression that really precedes another can appear in conscious¬ ness as succeeding it. Yet more: attention some¬ times serves to combine two sets of simultaneous im¬ pressions, and to make them seem as if proceeding from one source.
So much for the influence of attention alone. But what is attention? We reply, evidently an active process. When impressions are modified by atten¬ tion, they are actively modified. And if you ask about the nature of this active process, the reply is, attention, in its most elementary forms, is the same activity that in a more developed shape we commonly call will. We attend to one thing rather than to another, because we will to do so, and our will is here the elementary impulse to know. Our attention leads us at times into error. But this error is merely an accompaniment, the result of our will activity. We want to intensify an impression, to bring it within the sphere of knowledge. But in carrying out our impulse, we do more than we meant. W e not only bring something into clearer consciousness that was before out of clear consciousness, but we quali¬ tatively modify this thing in attending to it. I want to observe a series of beats, and in observing it, I make one beat in three or four seem heavier than the others, or I even alter the apparent length of one in¬ terval in three or four, by making it seem longer than the others. I observe a series of visual im¬ pressions, and at the same time a series of auditory impressions; if there is a certain agreement between them, I irresistibly unite these two series by my act of attention into one series, and refer them to a com¬ mon cause. And so in the other cases. Attention seems to defeat, in part, its own objfct. Bringing something into the field of knowledge seems to be a modifying, if not a transforming, process.
W e all know how this same law works on a higher plane. Giving our whole attention for a time to a particular subject seems necessary for the growth of our knowledge. Yet such attention, if long kept up, always modifies our power to know, affects our whole mental condition, and thus injures our power to ap¬ preciate the relations between the subject of our study and the other things in the world. Constant attention to one thing narrows our minds, until we fail to see the very thing we are looking at. Our lives are thus really passed in a constant flitting from one more or less partial and distorted view of things to another, from this one-sided judgment to that. Change the book you are reading, and your whole notion of the universe suffers some momentary change also. Think this week in the fashion of Carlyle, attending to things as he brings them to your attention, and human life — in fact, the whole world of being as you thought of it last week, when you were following some other guide — becomes mo¬ mentarily clouded. This truth seems out of relation to that. Your change of attention qualitatively alters your apprehension of truth. Attending now even to the same things, you view them in new lights. The alteration of mental attitude becomes confusing to yourself. But refuse to make any such changes, set¬ tle down steadfastly to some one way of regarding all things, and your world becomes yet more misty. You see only a few things, and those in such a bad light that you are in danger of utter darkness. Fre¬ quent change of mental view (we of course do not mean constant change of creed or of occupation, but only frequent alteration of the direction of our thought) is essential to mental health. Yet this alteration implies at least some temporary change in our knowing powers, and so some change in our ap¬ preciation of truth.
Before going on to speak of the effect of our own activity upon our knowledge, when attention is com- 316 THE RELIGIOUS ASPECT OE PHILOSOPHY bined with active recognition' of impressions, we want to formulate the law that governs the action of attention upon sense-impressions apart from rec¬ ognition. This law seems pretty well established by experience, and is, at all events, quite simple. It is this: Any act of attention tends, first, to strengthen the particular set of impressions to which it is at the moment adapted; and secondly, to modify those im¬ pressions in such a way as shall make the total im¬ pression derived from them all as simple an impres¬ sion as possible. These two statements could be reduced to one, thus: Attention constantly tends to make our consciousness more definite and less complex; that is, less confused and more united.
More definite, less confused attention tends to make consciousness; since, out of many vague impressions, attention fixes upon one or a few, and helps them to crowd out the others. Less complex and more united or integrated attention makes the impressions attended to; as when, for the indefinite multiplicity of the successive even beats of a watch or of an en¬ gine, attention substitutes the simpler form of a ris¬ ing and falling rhythm of more and less emphatic beats, or as when two parallel series of impressions are reduced to one, by combination. If impressions are so complex and so imperative in their demands as to impede greatly the simplifying and clarifying efforts of attention, the result is a disagreeable feel¬ ing of confusion, that may increase to violent pain.
This law, that our consciousness constantly tends to the minimum of complexity and to the maximum of definiteness, is of great importance for all our knowledge. Here we have a limitation that cannot be overleaped. Whatever we come to know, what¬ ever opinions we come to hold, our attention it is that makes all our knowing and all our believing possible; and tbe laws foDowed by this, our own activitv of attention will thus determine what we are to know and what we are to believe. If things have more than a certain complexity, not only will our limited powers of attention forbid us to unravel this complexity, but we shall strongly desire to believe the things actually much simpler than they are. For our thoughts about them will have a constant ten¬ dency to become as simple and definite as possible. Put a man into a perfect chaos of phenomena, sights, sounds, feelings; and if the man continued to exist, and to be rational at all, his attention would doubt¬ less soon find for him a way to make up some kind of rhythmic regularity, which he would impute to the things about him, so as to imagine that he had dis¬ covered some law of sequence in this mad new world. And thus, in every case where we fancy ourselves sure of a simple law of Nature, we must remember that a good deal of the fancied simplicity may be due in the given case not to Nature, but to the ineradi¬ cable prejudice of our own minds in favor of regular¬ ity and simplicity. All our thought is determined, in great measure, by this law of least effort, as it is found exemplified in our activity of attention.
But attention is not the only influence that goes to transform sense-impressions into knowledge. At¬ tention never works alone, but always in company with the active process of recognizing the present \ as in some way familiar, and of constructing in the present ideas of what is not present. At these two other active processes we must very briefly glance.
Recognition is involved in all knowledge. Recog¬ nition does not always mean a definite memory of a particular past experience that resembles a present one. On the contrary, recognition is frequently only a sense of familiarity with something now pres¬ ent, coupled with a more or less distinct applying of some predicate to this present thing. I recognize a horse, a landscape, a star, a friend, a piece of music, a book, when I feel more or less familiar with the impression of the object in question, and when, at the same time, I predicate more or less distinctly something of it. This, I say, is my friend, or the north star, or Webster’s Dictionary, or Smith’s horse. Or, perhaps, in recognizing, I recognize, not merely the whole object, but one of its qualities, or of its relation to other things. Then I say, this is large or small, good or bad, equal or unequal to another thing, and so on. In all these cases, recog¬ nition involves a lively reaction of my mind upon ex¬ ternal impressions. Recognition is not found apart from attention, though attention may exist more or less completely without recognition. Recognition completes what attention begins. The attentive man wants to know, the recognizing man knows, or thinks that he knows. Recognition implies accom¬ panying attention. Attention without recognition implies wonder, curiosity, perplexity, perhaps terror. But what is the law of this process of recognition? Does the process affect the impressions themselves that are the basis of the recognition? The answer is: Very distinctly, recognition does affect the im¬ pressions. The activity involved in recognition al¬ ters the data of sense, and that in almost every case. Two of the ways in which this alteration occurs are these: (1.) In recognizing, we complete present data by remembered past data, and so seem to expe¬ rience more than is actually given to our senses. Thus, then, in reading, we read over misprints (even against our own will), thinking that we see words when we do not see them, or when we see only parts of them. Again: in listening to an indistinct speaker we often supply what is lacking in the sounds he makes, and seem to hear whole words when we really hear but fragments of words. Or, merely whistling a few notes, we recall to ourselves, and seem to have present, the complex instrumental har¬ mony of some music that we have heard played.
Or, in dim twilight, we imagine the form of a man, and seem to see it plainly in detail, when, in fact, a mass of shrubbery, or a coat on a chair, is the one source of our impressions. In all these cases, the activity of recognition alters the data of sense, by adding to them, by filling out the sketch made by them. (2.) However, even the qualities of sense-im¬ pressions are altered according to the way in which we recognize their objects. The colors of a landscape are dimmer, and less significant as colors, so long as we recognize the objects in the landscape. Look under your arm, with head inverted, and the colors flash out with unwonted brilliancy. For when you so look, vou lose sight of the objects as such, and give your attention solely to the colors. Mistake a few brown leaves in some dark corner of a garden for some little animal, and the leaves take on for the moment the distinctive familiar color of the animal; and when you discover your blunder, you can catch the colors in the very act of fading into their dull, dry-leaf insignificance. Many facts of this sort are recorded by psychologists and by artists, and can be observed by any of us if we choose. To separate a sensation from its modifications that are produced by recognition is not a little difficult.
Now, in both these kinds of alteration a law is observed, very similar to the one previously noted. The alterations of the data of sense m the moment of recognition are alterations in the direction of simplic¬ ity and definiteness of consciousness. The present is assimilated to the past; the new is made to seem as familiar as possible. This reaction of the mind upon new impressions is easily seen in our thoughts and words in the first moment of great surprise or fright. When Macbeth turns from his door to the table, and sees the ghost of Banquo in his chair, his first words are not the “ Avaunt, and quit my sight 1 ” wherewith he greets the second appearance of the ghost, nor yet even the “ Which of you have done this? ” that he utters as soon as he recovers himself. No: his first conscious reaction, in pres¬ ence of the horrible impression, is a quiet remark, “ The table ’s full.” And when they tell him that there is a place reserved, he persists with a “ Where? ” In this scene, Shakespeare’s instinct is perfectly accurate. Our effort always is to make the new as familiar as possible, even when this new is inconceivably strange. It takes us some time to realize, as we say, a great change of any sort. Rec¬ ognition, however, is yet further modified by the in¬ terest with which we at any moment attend to things. But when we speak of interest, we are led to the third kind of active modification by which our minds determine for us what we know.
At every moment we are not merely receiving, at¬ tending, and recognizing, but we are constructing. Out of what from moment to moment comes to us, we are building up our ideas of past and future, and of the world of reality. Mere dead impressions are given. We turn them by our own act into symbols of a real universe. We thus constantly react upon what is given, and not only modify it, but even give it whatever significance it comes to possess. Now this reaction takes a multitude of forms, and cannot be fully discussed without far more than our present space. But we can name one or two prominent modes of reaction of mind upon sense-data in this province of mental life.
1. Definite memory is possible only through pres¬ ent active construction from the data of feeling. Nothing can come to us certifying for itself that it formed a part of our previous experience. M hen we know a thing as past, we actively project our idea of it into a conceived past time. Without this active interference of our own minds, eveiy thing would be but a present, and there would be no time for us, only fleeting life from moment to moment.
2. Definite belief in external reality is possible only through this active addition of something of our own to the impressions that are actually given to us. No external reality is given to us in the mere sense-impressions. What is outside of us cannot be at the same time within us. But out of what is in us, we construct an idea of an external world. To be sure this belief needs higher justification, like all other beliefs. But at the outset it is just an activ¬ ity of ours.
3. All abstract ideas, all general truths, all knowl¬ edge of necessary laws, all acceptance of doctrines, begin in like fashion, through an active process com¬ ing from within. Change the fashions of our men¬ tal activity, and nobody can tell how radically you would change our whole conception of the universe.
4. All this active construction from sense-impres¬ sions expresses certain fundamental interests that our human spirit takes in reality. We want to have a world of a particular character; and so, from sense-impressions, we are constantly trying to build up such a world. We are prejudiced in favor of regularity, necessity, and simplicity in the world; and so we continually manipulate the data of sense for the sake of building up a notion of a regular, necessary, and simple universe. And so, though it is true that our knowledge of the world is deter¬ mined by what is given to our senses, it is equally true that our idea of the world is determined quite as much by our own active combination, completion, anticipation of sense experience. Thus all knowing is, in a very deep sense, acting; it is, in fact, react¬ ing and creation. The most insignificant knowledge is in some sense an original product of the man who knows. In it is expressed his disposition, his power of attention, his skill in recognition, his interest in reality, his creative might. Exact knowledge is, in fact, best illustrated by cases where we ourselves make what we know. So only is mathematical knowledge possible; mathematical ideas are all prod¬ ucts of a constructive imagination. And so it is in all other thought-life. Mentally produce, and thou shalt know thy product. But we must remember, for what we produce we are in some sense morally responsible; and thus, in discussing the nature of knowledge, we are trespassing on the border-land of ethics.
To sum up all in a few words: Plainly, since ac¬ tive inner processes are forever modifying and build¬ ing our ideas; since our interest in what we wish to find does so much to determine what we do find; since we could not if we would reduce ourselves to mere registering machines, but remain always build¬ ers of our own little worlds, — it becomes us to con¬ sider well, and to choose the spirit in which we shall examine our experience. Every one is certain to be prejudiced, simply because he does not merely re¬ ceive experience, but himself acts, himself makes ex¬ perience. One great question for every truth-seeker is: In what sense, to what degree, with what motive, for what end, may I and should I be prejudiced? Most of us get our prejudices wholly from the fash¬ ions of other men. This is cowardly. We are re¬ sponsible for our own creed, and must make it by our own hard work. Therefore, the deepest and most important of all questions is the one, “ For what art thou at work V' It is useless to reply, “ 1 am merely noting down what I find in the world. I am not responsible for the facts' ’ The answer is, “ A mere note-book thou art not, but a man. These are never simply notes; thy thoughts are always transformed reality, never mere copies of reality. For thy transforming activity, as well as for thy skill in copying, thou art answerable.”
V.
V.
It is not then that postulates occur here and there in our thoughts, but that, without postulates, both practical life and the commonest results of the¬ ory, from the simplest impressions to the most valu¬ able beliefs, would be for most if not all of us ut¬ terly impossible; this it is which makes active faith so prominent a subject for philosophical considera¬ tion. An imperfect reflection makes that appear as blind faith which ought to appear as postulate. In¬ stead of saying that he takes all these things on risk, and because they are worth the risk, the natu¬ ral man is persuaded by such imperfect reflection to say that he trusts very ardently that he is running no risk at all. Or again: the natural man is moved to fear any examination into the bases of his thought, because he does not wish to discover that there is any risk there. And so we live dishonestly with our thoughts. Where there is a deeper basis, that involves more than mere risk, let us find it if we can. But where we have nothing better than active faith, let us discover the fact, and see clearly just why it is worth while to act in this way.
To speak more particularly of the postulates of developed science. The ancient discussions about the basis of physical knowledge of all sorts have had at least this as outcome, that it is useless to pre¬ tend to make science of any sort do without assump¬ tions, and equally useless to undertake the demon¬ stration of these assumptions by experience alone. No one has ever succeeded in accomplishing such a thing, and the only difference among thinkers about these assumptions is that some think it worth while to seek a transcendental basis for them all, while others insist that a transcendental basis is as impos¬ sible as a purely experimental basis is inadequate, and that in consequence we can only use the form of threat and say: Unless you make these assumptions, the spirit of science is not in you. As for the exact form that in more elaborate scientific work ought to be taken by these postulates, opinion differs very much, but an approximation to their sense may be attempted very briefly as follows.
In addition to those postulates that, as we have seen, accompany and condition all thinking alike, science may be considered as making a more special assumption. This assumption has been well defined by Professor Avenarius, in his well-known essay on “ Die Philosophic als Denken der Welt Gemass dem Princip des kleinsten Kraftmasses.” He regards it as an outcome of the general law of parsimony that governs all mental work. The world of phenomena is conceived at any stage in the simplest form, and