are not the whole of our mental Phenomena. They, our sensations, are the events that occur to us without our direct voluntary effort, and seem to be the effects of something not ourselves. Whether they mean anything more than themselves is the question to be discussed in the present chapter, but they are certainly that type of occurrence or experience which enlists our curiosity and interest most distinctly. They seem to demand some explanation of their occurrence, especially in that they are extremely numerous and variable in each sense-organism, though we do not rely upon this explanation as a measure of their practical value for immediate conduct. They are conceded to be events which do not explain themselves, whether we adopt the realistic or the idealistic theory of their meaning, the one seeking their sole cause outside the subject, and the other partly in the actions or reactions of the subject. In this conception of a cause for them they seem to imply something other than themselves, and, as they represent but one class of mental phenomena instead of the sole type of them, we have to examine the complementary functions of mind that can look at these sensations and assign them a meaning. I do not here refer to self-consciousness and its numerous data, as they are not of interest in our present problem, though they are important in the final discussion of philosophic questions: but I refer to those mental acts or processes which apply alike to sensations and reflections, as the various states of consciousness may be called. These functions I shall call
judgment, thus dividing the material of the present problem into Sensations and Judgments, and so reduce the fundamental processes of the mind to two types. Sensations are facts or phenomena which are to be explained. Judgments are the acts of mind explaining them.
Judgment, as here conceived, is the act of mind which interprets and explains facts, as in referring a phenomenon to its cause or to the class to which it belongs. Such judgments are governed by certain principles or laws of thought determining their meaning. These laws are sometimes called necessary assumptions in contradistinction to those assumptions which are not well accredited, or, if well accredited, may require proof. But whatever we call them, they are those conceptions which are necessary to the interpretation and explanation of all phenomena or events. They indicate the nature of the judgments formed in connection with all facts and things with whose occurrence or existence alone we are not satisfied, as when we refer a fact to some antecedent even, or to some cause or ground, and when we refer a thing or fact to that with which it may be classed or from which it may be distinguished. What I have said indicates two general principles regulating our judgments or constitutes their meaning for our knowledge. They are the
principle of causality or ground, and the principle of kind or type. The one explains things by reference to what produces them, and the other by their classification. The judgments which represent the application of the principle of causality are found in those propositions which present the relation between substance and attribute, and the judgments which represent the application of the principle of kind or type are those propositions which present the relation between genus and species, or between class terms. We may call the first form of these judgments the qualitative or intensive judgment, and the second the quantitative or extensive judgment. But I am not concerned with a technical name that is less clear than their definition, and so leave the adoption of such titles to the reader. It is what we mean by the relation between substance and attribute on the one hand and between genus and species, or class terms, on the other, that is the important fact to keep in mind. The first type of these judgments is illustrated by such propositions as "Glass is transparent," "Wood is hard," or "Fire burns," and the second by such propositions as "Horses are quadrupeds," "Wheat is a food," or "Christianity is a religion." Now absolutely all propositions can be reduced to one or the other of these types of thought, and by the proper form of expression the meaning of one type can be converted into the other, or rather the form of expression may make apparent a meaning latent in the other.
The first judgment that we form on the occasion of sensation is that it has a cause. Of course, in adult and mature experience we form some judgment of
what the cause is, but it is probable that our earliest judgments represent very vague and indefinite conceptions of the cause, and, when we ascertain what place the subject has in determining the nature of sensation, we very quickly perceive that
what the cause may be is not so clear as we thought it was in our earlier and more naive experience. The utmost that we probably say or think in the early period of life is that sensations have a cause, and that this cause is either without or within the body, extra-organic or intra-organic. I need not here go into any minute or profound study either of the processes by which we do this or of the validity of these judgments. What the nature of things may be, whether mind or matter, both or neither, need not occupy us. Any conclusion that we might adopt regarding these will not affect the fact that our normal sensations are distinguished with practical clearness from the abnormal and are caused by external agencies.
I have just said that these judgments are formed severally upon individual sensations, and when this is the case the conception of what the cause may be is very indefinite. It is little more than the fact that sensations are caused by something, and that their occurrence is not due to chance or spontaneous generation. The knowledge thus acquired is very simple and meagre. Thus, if I have a sensation of color, the judgment of causality formed on the occasion of the experience would be that
something produced it. We might be uncertain whether it was ourselves or something else. But we should not think that the sensation occurred without a cause of any kind. We should probably think of the cause in this early stage as something indefinite, and perhaps the impersonal judgment, "It has color," or "It causes this," would be the form which our mental act would take at the time. But not to go into this elaborately, the main point to be illustrated is the fact that each sensation by itself would not give the complex and systematic unity which our mature judgments actually have. They would result in a vast system of judgments without unity or connection, and the world would appear quite different from what it actually does appear in our more complex judgments. Such conceptions as are represented in the terms, "trees," "houses," "animals," "food," "morality," "politics," "religion," etc., would not appear in our thought. We should only have a class of disconnected and simple, instead of complex, things involved in our judgments. How, then, do we get any unity and complexity in our conceptions?
Such conceptions as I have enumerated, namely, "trees," "houses," etc., represent a group of qualities or properties associated with the same subject or cause. Each property corresponds to a particular kind of sensation or effect produced upon the mind. How do we get them together?
The answer to this question will be quite simple and clear. We begin the process of associating these different qualities by having
simultaneous sensations initiated from the same point in space. If I find that a sound issues from the same point as my color and tactual sensations, I refer it to the same object or cause, and so it would be with all the sensations and properties that I experience under like conditions. The fact that they occur together and are referable to the same cause, this being due to the unity of time and space for their occurrence, gives me the conception of a unified whole, a single substance or cause for a group of qualities, and I thus have the conception complex in its numerical of a single complex object, attributes, such as "Charter Oak," "Gladstone," "Plato," etc. These are individual groups of qualities which are not duplicated in our experience, and do not require comparison with others in the formation of them.
I see a yellow color and find also a certain taste associated with it and a soft tactual quality. I as a name. I with these, and retain the same name for the subject. If I have never experienced anything like this particular object, the name for it will be that of a singular term, as illustrated in the singular concepts above.
But I do not stop with this process of associating or synthetizing qualities and sensations. This is a comparatively simple and elementary process, and the conceptions which we actually denominate by all but proper names represent an additional act of judgment. Hence the next step, after forming the simple associations, or perhaps better, consociations of separate sensations and qualities in the same subject, is to compare the different objects of experience, and sign them the same subject and give it may find other qualities also associate classify or distinguish them. If we see two objects at the same time and they are essentially alike, we can apply the same term to them, and again, if we see two objects at different times and they have the same essential qualities, we may also apply the same term to them. In the former of these acts no memory is involved; in the latter memory is added to the process. In both there is comparison of one experience or object with another, and they are classified together, if they are essentially the same in nature, and distinguished if they are different in characteristics. Thus, if I find two balls of the same size, color, density, structure, weight, and uses with any other identical properties, I can denominate them by the same name, such as cannon-balls. But if the balls differ in all these qualities, I should have to denominate them by different terms, such as "apples" and "bullets." They may have other similar properties that enable us to call them
matter, but they will remain distinguished as species nevertheless, while the more general term will be the genus representative of the common properties. This whole process of classification simplifies the use of language and still further unifies experience. All objects of an essentially like character can have common conceptions and terms, and those that essentially differ may have that difference marked in the proper manner, suitable to the needs of practical life.
The principle on which our judgments of this character proceed is what I have called the principle of kind or type. In metaphysical parlance it is called the principle of identity and difference, to distinguish it from that of causality. Perhaps some would prefer to call it the principle of similarity and diversity. It is, however, well enough understood in traditional parlance as that of identity and difference, which I here denominate for the general understanding as that of kind or type. By it we compare and distinguish objects and systematize our knowledge of the world to a much larger extent than we can by the application of causality alone. We reduce the number of causes in things to a smaller quantity, and ultimately to a single one, if the facts justify it. The process applies to all our conceptions involving class terms, and so represents the unification and systematization of knowledge over the whole complex field of experience.
The two general kinds of judgment which we have been discussing, and which I previously named the intensive and extensive, may be called, for greater clearness, causal and classifying judgments. Causal judgments are those which refer experiences and facts to the agents that produce them. Classifying judgments are those which reduce experiences and facts to specific and generic types. As I have remarked above, the former judgments represent the relation between substance and attribute; the latter that of genus and species, or class terms. These processes represent the whole of our normal activities of thought in the interpretation and explanation of facts, and whatever principles we shall have to appeal to in the study of exceptional facts must be adjustable to these facts in some manner. We in some way get beyond sensations or phenomena in these processes, and so satisfy our expectation that facts do not occur of themselves, and that they are so related to each other as to give a world of unity and connection. The next step is to see what means we have for distinguishing between normal and abnormal judgments in this field.
There are two important ideas which these fundamental judgments represent. They have been mentioned above, but I recur to them here that I may formulate them for future use when I come to study the claims of supernormal knowledge. They are (1) that the causal judgment goes outside the organism for the explanation of the occurrence of normal sensations, and (2) that the classifying judgments reduce the number of causes to a minimum. We shall have occasion later to use these maxims frequently.
The point, however, at which skepticism begins in regard to the causal judgments of sense is that which represents the doubt about our primitive and naive perceptions, and it may admit the general principle and raise the doubt about the special application of it. The skeptic may well admit that sensations are caused, but he may wish to ask whether this cause may not be the action of the mind and not an external agent. The fact which may seem to favor his doubts is that which represents sensations and states of consciousness as
our own. In some way we relate them to ourselves, that is, the mind or organism, and not as events or states of an external object, and with this we may ask whether the subject might not thus be the cause of them, instead of the external world being the cause. The additional circumstance that suggests this view is the discovery that our sensations are not presentative or representative of objects, but actions or reactions of our minds or brains. This, as we have remarked before, requires us to look at the subject as well as the object, at the organism as well as the external thing, for some explanation of the facts. If, then, we rest satisfied that our minds are the cause of sensations, and not the external world, we have no credentials for extraorganic causes of any kind, and the causal judgment could not be used to guarantee external reality.
I doubt, however, whether any one seriously entertains these assumed difficulties as genuine ones. The question may be put, and however it is answered by the skeptic the normal mind will not be greatly puzzled by it, especially if it is given to the analysis of its conceptions, as this habit will quickly suggest the equivocations in the term cause that give the skeptic the whole apparent force of his query. But, though we see easily enough that the difficulty is not a real one, it does suggest, if it does not make imperative, the study of facts which are held to illustrate and prove the complexity of our mental states and convictions, and the illusions to which we are now and then exposed.
But there are facts which seem to vindicate the judgment of external causality against all suspicion. Some of them have been suggested in the discussion of sense-perception. But I was there discussing the meaning of sensation for practical life and action, without involving it in the problem of causality and even supposing that it was a wholly subjective affair. Here, however, I am concerned with the additional factor introduced into the problem of knowledge by the judgment of causality, and especially by that of external causality. We may distinguish between values in experiences, and we may determine that type which we have to regard in our actions and expectations without raising the question of causality external or internal. But we do not thereby escape the necessity of reckoning with such causality, especially if the external causal agency be intelligent, human or divine. The test of its existence, therefore, becomes a matter of some importance. Hence we may have to repeat in this new relation some of the points concerned in the last chapter, and in repeating them add others to the list of criteria that may enable us to distinguish between normal and abnormal phenomena.
The first fact vindictive of external causality is the circumstance that we do not voluntarily and directly produce our own sensations. We may produce voluntary movements in our organism, from which sensations follow as physical or other consequences, but we cannot produce any particular sensation directly, at least normally, by a
feat of will. Sensations are purely involuntary affairs and also unconscious affairs in so far as they are not consciously caused. We may be aware of them after they occur, but we are not aware of what sensations are going to occur, and cannot anticipate them until experience has taught us the law of their occurrence, and even this anticipation is in no respect related to the causal agency of consciousness as a direct influence. Hence we do not produce sensations by thinking of them in any normal manner, or by expecting them. They may be purely subjective affairs, nevertheless, as subliminal creations, but this possibility does not affect their relation to our voluntary and conscious activity. This is not their direct cause, and, as they do not follow any known law of subconscious causation, we have every reason to suppose that the cause is foreign to the subject, at least in all instances which we have ground to believe are normal.
The reply to this would be the comparatively recent fact of science, alluded to above, that there are all sorts of phenomena occurring within the organism that are not externally initiated in any such way as normal sensations are supposed to be. There are involuntary muscular actions that are not traceable to any such correlation with external events as is noticeable with many voluntary actions. There is also the whole field of subliminal mental activities that are neither voluntary nor conscious, and yet they do not seem to be coordinated with any known external stimuli. They are manifest in somnambulism and hypnotic states, in automatic writing and the phenomena of secondary personality, and many facts that exhibit themselves in deliria. These facts suggest that, even though sensations may not be consciously produced by ourselves, they might be produced unconsciously by the organism or that part of ourselves which represents the basis of subliminal acts, sensory or motor. I say suggest, because I am far from admitting that they are evidence of a subjective origin for sensation normally understood. I have mentioned them only in deference to that skeptical temperament which can often give evidential trouble more than it can influence conviction even on its own side. Of course, if some things are produced subjectively, why may not all of them be? But, while facts, like subliminal actions, may demand that we seek and establish an adequate criterion for the distinction we make between objective and subjective causality, it is another thing for it to treat its queries as implying a totally subjective agency in the phenomena concerned. We might have as good reason for supposing that they are all objectively instigated because some of them are, and that is a position which even the skeptic cannot admit or urge without eliminating the ground of his doubts about the objective. We may have as good evidence of external causality as we have of the internal, though we may have difficulty in applying a criterion to distinguish between them in concrete instances, while not being in doubt about the majority of them.
But the point of defence for the external causal judgment here is that there is no such system in the occurrence of such phenomena supposedly initiated by unconscious activities as we find in normal experiences, at least so-called. There are plenty of systematic mental conceptions so originated, but not sensations, in so far as we are able to test them. Especially there is no such synthetic or associated grouping of different sensations as we find them in the cases where the ordinary judgment holds good. That is, sensations of touch and hearing do not follow supposed, or even proved, subjective visual experiences, as they should follow them if all were subjective, because that is the law of our supposedly normal sensations. Hence we feel constrained by the systematic way in which our normal sensations occur to refer them to an external source, whatever we may say or think about their being our own, and whatever we admit about the occasional influence of subjective agencies in simulating them. There is no such systematic association of simulated sensations in different senses by subjective causes as we rely upon to test our objective realities.
There is another important fact pointing in the same direction. It is that the vindication of the external causal judgment does not depend upon denying the function of the mind or brain, either to determine the nature of sensation or to originate subconscious states that issue occasionally in abnormal sensations or the simulation of real sensations. All that the notion of external causality requires is that it should be responsible for the
occurrence of sensations and not for their nature. We may grant all that the skeptic may wish to claim about the agency or influence of the mind on the character of sensations. This claim does not carry with it the explanation of the time, regularity, and systematic occurrence and association of different sensations, but only their nature or qualitative character; that is, their non-representative content in relation to the real or supposed external cause. The objective cause is the primary agent in determining whether normal sensations shall occur at all, and the subject, mind,
or organism is the agent that determines their nature, that is, their quality, when they do occur.
These arguments have been discussed on the assumption that we have no other criterion of external causality than the mere regularity of individual sensations unassociated with each other. But in actual experience the test is somewhat different, especially when we wish to know the particular concrete object or cause, and this will be true whether this different test is any more valid or not than the one just indicated. This additional fact is that of testing the judgment formed on the occasion of one sensation by the proper occurrence or concurrence of a sensation in another sensory organism. This is to test the case by a number of associated sensations in different organs, or technically, by synthetically associated experiences. Thus, if we have a visual sensation whose external cause we may suspect as illusory, we may test its objective source by trying to touch the apparent object, or obtain from it experiences of taste, sound, or other sensation. I am not supposing here that every visible object is tangible. There may be visible or audible objects that are not tangible, so far as I know, and I shall not deny their existence, but this is not the condition of our usual experience. Generally we find that any visible reality is also tangible, and we have the right to expect on the basis of this usual experience that tangibility will follow upon visibility. For our normal experience, as we know it usually, objects are a complexus of qualities that affect different senses, and that is what we usually mean by concrete external realities. Hence, whatever existence may be for merely visual experience, we can test our usual conception of externality only by an appeal to synthetic experience. This is correcting the possible illusion of interpretation in one sense by the action of another, and on the assumption that the probabilities are against mere chance of both senses being deceived in the causal inference. For in every sensory experience involving a possible synthesis of sensations there is the causal inference as well as the causal judgment. The causal judgment merely asserts that the sensation has a cause, or that its cause is external, but it does not assert that the cause is also tactual or audible. It infers or expects this from previous experience of their association or synthesis.
Thus, to illustrate the whole case, if I see an image in a mirror and take it for a real object, as children and savages often do, I may in various ways ascertain whether it represents a reality where it is seen or not. I may try to touch the apparent object, and, failing in this expected result, I come to the conclusion that there is an error of judgment somewhere. I may study the constancy of this image in relation to other facts, and if I find that it moves with the object which the image supposedly represents, I do not attempt to touch it or to test it in that way, perceiving that the phenomenon is not a normally usual one. Or I may try to see it from different points of view, and failing that, I may also conclude that the phenomenon is in some way subjective. It will be the synthetic association of tactual and other sensations, as well as the synthesis of recurrent sensations in the same organ from different points of view and at different times, that will assure the conviction of externality, as usually conceived, where individual and transient experiences will not certify for us. It is important to remark, however, that the illusion in the instance under notice is not regarding the externality of the cause, its external
existence, but the locus of it, its position in space. We find on all examination of such cases that the mistake was in the localization of the object, and not in its external existence. It may be much the same with other experiences. Hence the very reference to such illusions may only confirm, instead of nullify, our ordinary judgments.
It is the failure to secure other sensations than the given one that strengthens the suspicion of error when it is feared, and to the same extent their association or synthesis encourages the belief in objectivity. The casual instead of causal synthesis of illusions would be hard to accept. But the skeptic would have to assume a causal connection between different sensations when he supposes that two or more of them are associated regularly and without a correlative external cause. Otherwise he could not expect any coincidence of the phenomena as he finds them, and anything like a causal nexus in such cases would involve him in the want of a test for illusion itself, since the usual criterion of an illusion is just this absence of causal connection or the properly associated sensation when the external causal judgment would require it. Let me illustrate.
The savage thinks at first that the image which he sees in a mirror is a real object, where it is apparently situated behind the glass. Perhaps in some cases we may not know of the mirror, and have to discover it by first ascertaining the error of our judgment about the apparent object. The inference of the savage is natural enough, and would be made by any one who had not grown familiar with the phenomenon. But the savage proceeds to test his inference by seeking the object behind the mirror, and, failing to find it, he is more or less assured that there is some illusion. He does not realize his expectations where they would be realized if the proper external object were there as apparently seen, or if there were any causal nexus between the first visual image and the expected tactual sensation. If the object were not there and the occurrence of the appropriate sensations took place, we should have to suppose the causal connection to be between the sensations. But the absence of this sequence indicates that we must seek the causal nexus elsewhere than between the sensations themselves. In my normal experience, as we name the usual order of mental events, I do not find any such invariable synthesis or nexus of sensations as the causal judgment would require. Under one set of conditions I find a given association and under another a totally different association of them. This fact shows that there is no inherent causal relation per se between the sensations, and if that causal nexus does not naturally exist between them, it would be extremely improbable that two or more senses would have so regularly simultaneous
illusions about the same apparent object. If this, however, were an actual fact in an occasional instance, it would still be quite improbable that the coincidence would be a constant one. If it were a constant one, we might have evidence of a causal connection which would prevent the discovery of illusion in any case, and certainly, whatever we should call the phenomenon in such a case, it would not be illusion as we now understand it.
Moreover, the very fact that we can recognize subjective agency at all, and clearly distinguish in most cases between it and what we regard as objective or external, is in favor of the belief that some experiences represent a causality not our own, even though we cannot prove the contention, and we only await a suitable criterion for determining this source. This capacity for distinguishing the different types of experience requires us to look for different causes, and sensations of the normal and involuntary class show such a relation to all that we can easily trace to our conscious and unconscious causality that the only natural thing for us to do is to refer their Origin, that is, their occasioning cause, to something else than ourselves and so make them incident to extra-organic initiation.
Perhaps the most decisive proof of this extraorganic causality for normal sensations is a certain characteristic difference in them in comparison with Such as we believe or can prove to be subjective. The normal sensations have a fixity and regularity in their associations or occurrence in certain conditions which the subjective do not have in the same conditions. An illusion will not persist so long as a normal sensation, and yields to investigation and experiment when the normal will not be eliminated. A normal sensation will preserve its character and uniformity of occurrence with the change of all conditions but that of its actual cause objectively considered; an illusion is more variable. The least modification of our environment, say as in case of the image in a mirror, will dispel many illusions, when a normal sensation will not undergo any alteration in the same circumstances. Again the illustration of the image in the mirror applies. A real object would be found to respond to experiment, though the place of the observer change, while an illusory sensation would disappear or show certain changes that betrayed its purely subjective character. For instance, again our normal perception of the sun has a fixity and uniformity of relative position with reference to various associated sensations that our after-image of it does not have. We have to be definitely related to a fixed environment in order to have a certain sensation of the sun that even purports to be real, but the after-image can be seen anywhere under the proper conditions. This objective fixity of something in contrast with the subjective caprice and variability of what we discover in illusion is a circumstance of great importance, and it coincides with all the other facts that point to a cause necessarily distinguishable from subjective agency alone. But the conviction of it will not be accomplished by any off hand methods. It will require the scientific spirit and method to protect judgment from mistakes.
I have not discussed the processes of inference and reasoning. They are in fact forms of judgment, but since they represent an application of such as one either a little different from the simplest causal or classifying judgments or are more complex instances of them, they should receive some notice as interpreting functions of our minds. We may consider inference and reasoning as identical, if we wish so to characterize the inductive and deductive processes as reasoning acts. But as one gives a certitude which the other does not, it is customary with some writers to call the inductive process inference, and the deductive process reasoning. I regard the two as essentially the same psychologically, but as different in the content and certitude of the conviction produced by them. In fact, some writers as readily use inference to describe the deductive reasoning in the conclusion as they would inductive ratiocination. But if the reader will understand the matter better by confining inference to inductive expectations and reasoning to deductive certitude, I shall not object to that usage of the terms. I mean here to speak indifferently of inference in both processes.
In a broad sense inference is reasoning to what we do not see at the time. It may be expectation of future facts or the presence in reality of concealed facts. Thus, in any particular sensation, I may infer that another is possible if tried. If I see a certain yellow color, I may infer that the object having this color will have a certain taste, say that of an orange. If I see a certain type of cloud, I may infer that it will rain, or if I see dew on the grass regularly after clear nights, I may infer that it is due to the radiation of the earth's heat absorbed during the day. And so on with many similar illustrations. In all of them we are supposing the existence of some fact, present or future, that is not an object of immediate observation or is not a part of the present sensation or experience. I have virtually indicated this conception of it in the instances mentioned to illustrate the process of testing the correctness of the inference for the judgment of external causality. The judgment of causality is most intimately connected with the explanation of the given sensation, and it is only an inference of the existence of another than the given quality in the same cause that suggests the need of certifying the objectivity of meaning in the present sensation. But this process of anticipating experience, of conjecturing the existence of realities not immediately revealed, is the one that lies at the basis of all scientific and philosophic reflection and gives rise to the systems of philosophic and other types of theories taking us far beyond present facts.
But the condition of doing this legitimately is the nature of previous experience. We do not and would not infer to future events or to the concealed presence of facts not actually observed were it not that the association of the inferred fact and the present sensation has been a more or less frequent experience in the past. We have to realize a synthesis or association of certain experiences frequently enough to suggest the probability that the presently unobserved fact will reveal itself at the proper time an under the appropriate circumstances. The various judgments of causality and kind have to be frequent facts of experience, and their associated incident have to be such a law of that experience that we would have to surrender the unity and uniformity of the world to discredit inferences of expectation. Hence inferential and reasoning processes depend on experience for their justification, and so they have all the liability to mistake and illusion that all anticipations and expectations have. The less frequent the experiences which suggest them, and the less constant a given set of syntheses and associations, the greater the exposure to mistake, and hence the dubious character of those speculative constructions which are based upon small inductions or few data in experience. Here we need especially to be on our guard, as actual experience has first to suggest an inference and to confirm it when suggested. The field of immediate certitude is an exceedingly small one.
We have then these three processes of interpretation and explanation. Two of them, the judgments of causality and of classification, relate facts, the one to a cause and the other to kind or type, to similar or different things. The third anticipates other facts than those immediately present in consciousness. The causal judgment may apply to what is present or what is concealed, and so also the judgment of kind. We may see the causal connection between two present facts or refer a fact to something not, seen, and we may classify or distinguish two present facts or similarly relate one to a fact or facts not present. In both we may include in our view of things much that is beyond the present sensations. In inferences and reasoning we go still farther, and the measure of assurance that we can rightly possess in the act will depend upon the amount of experience and observation that we have in the association of facts and the care with which we have done our work. Or perhaps we may have an illegitimate assurance from the very carelessness with which we have made our observations and neglected the essential for the unessential relations of things. But he who has raised the question about the right connections in facts will have his assurances determined by the insight and care with which he has made his observations of phenomena. Otherwise he will be the victim of all sorts of illusions. The actually observed constancy of phenomena and their association or synthesis, often for a long period of time, is necessary to distinguish a casual from a causal, a contingent from a necessary connection or relation, and many minds rush off into speculative theories of the wildest type just for the lack of that care which distinguishes the scientific temperament, a temperament that may not be characterized so much by doubt and denial as by prudence and suspense of judgment until proper credentials can be secured for its convictions.
I have dwelt upon the problem of illusion and external causality for our sensory experience because I have wished to emphasize the difficulty of captious assertion about such an agency right in our normal life, especially by the reflective mind. I quite accept the fact that in our ordinary experience we have no trouble in deciding what is normal and objective and what is abnormal and subjective. The very number of our illusory experiences, to say nothing of their intrinsic character, makes them a negligible quantity in our practical life usually; and it is our immediate practical life that is mainly concerned, though a remoter life may be equally concerned in the more careful determination of the relations between the normal and the abnormal, to say nothing of the value attaching to the more scientific and definite knowledge of the abnormal and its relation to all sorts of ethical demands in our social relations to each other. When we come to scientific reflection and the search for an infallible mark of the objective and the subjective, we begin to encounter a certain kind of difficulty, and we find that we have often only been measuring off one illusory certainty against another. The importance of the reflective standard in the study of experience shows itself in the investigation of those abnormal phenomena about which there is no doubt rather than in those of the average normal experience, for it teaches us prudence and care in the classification of those cases which may not require the treatment that rough medical standards would misjudge and maltreat. But no matter how clear the criterion is to the expert physician and psychologist for distinguishing the normal from the abnormal, - and it is not always clear to either of them, - it is not one that can be made easily apparent to the naive intellect, and hence skepticism always has an advantage when suggesting caution or doubt about human judgment or the interpretation of experience.
When we come to consider judgments based upon residual phenomena and arguing for extra-organic causes, especially of a certain specific kind, we can appreciate the strength of the skeptical plea for the extent to which subjective influences must teach us prudence and cautiousness. The truth of this will come home to all of us when we are asked to consider the appeal to those extra-organic agencies with which we are not familiar in ordinary life at all and when the defence of them disregards the existence and nature of the abnormal altogether. In normal experience the mere statistical relation between the familiar and the exceptional is a sufficient guide for practical life, since it is a mere inductive question of the chances or probabilities for one or the other type of experience in selecting which shall determine our conduct. But when it comes to the invocation of causes, external or internal, which are not familiar and which do not have any systematic relation to our normal and practical life, it is a matter of some importance that our evidence for exceptional causes should be commensurate in quality and quantity with the extent of the conclusion drawn. Hence the value of knowing the nature and limits of assured judgment in our normal life and the relation of the abnormal to it. The criterion may not be a simple one, but such as it is it must suffice to justify some measure of prevision in the occurrence or expectation of events, and mark that measure of constancy in the occurrence and association of different phenomena that will place us beyond the casual in the judgment of things. We must have some definite conception of an order not determined by the caprice of our own actions, and representing a more or less fixed relation to an order that conditions our natural development instead of an order which our minds create against the forces upon which we depend for normal growth, mental and physical. We have to be extremely cautious about estimating reality by retrospections and expectations that are not read from the nature of the passing moment. We may be equally deceived by too much attention to the phenomenal movement of the present experience. Hence, between this Scylla and Charybdis, between the past and the future on the one hand, and between both and the present moment on the other, we have to steer through dangerous narrows, and by a judicious combination of memory and verified inferences secure that standard of constancy and change which will measure in proper balance the claims of expectation and doubt.
> Previous > Next