ATTENTION.
General Character of this Power.—It has not been usual to treat of Attention as one of the distinct faculties of the mind. It is doubtless a power which the mind possesses, but like the power of conception, or more generally the power of thought and mental apprehension, it is involved in and underlies the exercise of all the specific mental faculties. Nor is it, like consciousness, confined to a distinct department of knowledge, viz., the knowledge of our own mental states. It is subsidiary to the other mental powers, rather than a faculty of original and independent knowledge. It originates nothing—teaches nothing—puts us in possession of no new truth—has no distinct field and province of its own. And yet without it other faculties would be of little avail.
Definitions.—If it were necessary to define a term so well understood, we might describe it as the power which the mind has of directing its thoughts, purposely and voluntarily, to some one object, to the exclusion of others. It is described by Dr. Wayland as a sort of voluntary consciousness, a condition of mind in which our consciousness is excited and directed by an act of the will. He speaks also of an involuntary attention, a state of mind in which our thoughts, without effort or purpose of our own, are engrossed by objects of an exciting nature. It may be questioned, perhaps, whether this is properly attention. Only in so far as attention is a voluntary act is it properly apower of the mind, and only in so far does it differ from the simple activity of thought, or of consciousness. The latter is always involuntary, and in this it differs from attention.
Instances in Illustration.—It can hardly be necessary to illustrate by example the nature of a faculty so constantly in exercise. Every one perceives, for instance, the difference between the careless perusal of an author—the eye passing listlessly over the pages, and the mind receiving little or no impression from its statements—and the reading of the same volume with fixed and careful attention, every word observed, every sentiment weighed, and the whole mental energy directed to the subject in hand. We pass, in the streets of a crowded and busy city, many persons whom we do not stop to observe, and of whose appearance we could afterward give no account whatever. Presently, some one in the crowd attracts our notice. We observe his appearance, we watch his movements, we notice his peculiarities of dress, gait, manners, etc., and are able afterward to describe them with some degree of minuteness. In the former case we perceive, but do not attend. In the latter, we attend, in order to perceive.
Sometimes the sole Occupation.—Attention seems to be at times the sole occupation of the mind for the moment, as when we have heard some sound that attracts our notice, and are listening for its repetition. In this case the other faculties are for the time held in suspense, and we are, as we say, all attention. The posture naturally assumed in such a case is that indicated by the etymology of the word, and may have suggested its use to designate this faculty, viz., attention—ad-tendo—abending to, astretching toward, the object of interest.
Analysis of the mental Process in Attention.—If we closely analyze the process of our minds in the exercise of this power, we shall find, I think, that it consists chiefly in this—the arresting and detaining the thoughts, excluding thus the exercise of other forms of mental activity, inconsequence of which the mind is left free to direct its whole energy to the one object in view. The process may be compared to the operation of the detent in machinery, which checks the wheels that are in rapid motion, and gives opportunity for any desired change; while it may be compared, as regards the result of its action, to the helm that directs the motion of the ship, now this way, now that, as the helmsman wills.
Objects of Attention.—The objects of attention are of course as various as the objects of thought. Like consciousness, it may confine itself to our own mental states; and, unlike consciousness, it may comprehend also the entire range of objective reality. In the former case it is more commonly designated by the term reflection, in the latter, observation.
Importance of Habits of Attention.—The importance of habits of attention, of the due exercise and development of this faculty of the mind, is too obvious to require special comment. The power of controlling one's own mental activity, of directing it at will into whatever channels the occasion may demand, of excluding for this purpose all other and irrelevant ideas, and concentrating the energies of the mind on the one object of thought before it, is a power of the highest value, an attainment worth any effort, and which, in the different degrees in which it is possessed, goes far to make the difference between one mind and another in the realm of thought and intellectual greatness. While the attention is divided and the mind distracted among a variety of objects, it can apprehend nothing clearly and definitely; the rays are not brought to a focus, and the mental eye, instead of a clear and well-defined image, perceives nothing but a shadowy and confused outline. The mind while in this state acts to little purpose. It is shorn of its strength.
The power of commanding the attention and concentrating the mental energy upon a given object, is, however, apower not easily acquired nor always possessed. The difficulty of the attainment is hardly less than its importance. It can be made only by earnest effort, resolute purpose, diligent culture and training. There must be strength of will to take command of the mental faculties, and make them subservient to its purpose. There must be determination to succeed, and a wise discipline and exercise of the mind with reference to the end in view. This faculty, like every other, requires education in order to its due development.
Whether certain Acts are performed without any Degree of Attention.—It is a question somewhat discussed among philosophers, whether those acts which from habit we have learned to perform with great facility, and, as we say, almost without thinking, are strictly voluntary; whether they do or do not involve an exercise of attention. Every one is aware of the facility acquired by practice in many manual and mechanical operations, as well as in those more properly intellectual. A musician sits at his instrument, scarcely conscious of what he is doing, his attention absorbed, it may be, with some engrossing topic of thought or conversation, while his fingers wanderad libitumamong the keys and strike the notes of some familiar tune. Is there in such a case a special act of volition and attention preceding each movement of the fingers as they glide over the keys? And in more rapid playing, even when the attention is in general directed to the act performed,i. e., the execution of the piece, is there still a special act of attention to the production of each note as they follow each other with almost inconceivable rapidity? Dr. Stahl, Dr. Reid and others, especially many able physiologists, have answered this question in the negative, pronouncing the acts in question to be merely automatic and mechanical, and not properly involving any activity of mind. The mind, they would say, forms the general purpose to execute the given piece, but the particular movements and muscular contractions requisite to produce the individual notes, are, for themost part, involuntary, the result of habit, not of special attention or volition.
The opposite View.—On the other hand, Mr. Stewart maintains that all such acts, however easily and rapidly performed, do involve mental activity, some degree of attention, some special volition to produce them, although we may not be able to recollect those volitions afterward. The different steps of the process are, by the association of ideas, so connected, that they present themselves successively to the mind without any effort to recall them, without any hesitation or reflection on our part, and with a rapidity proportioned to our experience. The attention and the volition are instantaneous, and therefore not subsequently recollected. Still, he would say, the fact that we do not recollect them is no proof that we did not exercise them. The musician can, at will, perform the piece so slowly, as to be able to observe and recall the special act of attention to each note, and of volition to produce it. The difference in the two cases lies in the rapidity of the movement, not in the nature of the operation.
Objection to this View.—The only objection to this view, of much weight, is the extreme rapidity of mental action, which this view supposes. An accomplished speaker will pronounce, it is said, from two to four hundred words, or from one to two thousand letters in a minute, and each letter requires a distinct contraction of the muscles, many of them, indeed, several contractions. Shall we suppose then so many thousand acts of attention and volition in a minute?
Reply to this Objection.—To this it may be replied that the very objection carries with it its own answer, since if it be true that the muscles of the body move with such wonderful rapidity, it is surely not incredible that the mind should be at least equally rapid in its movements with the body. To show that both mind and body often do act with great rapidity, Mr. Stewart cites the case of the equilibrist, whobalances himself on the slack rope, and at the same time balances a number of rods or balls upon his chin, his position every instant changing, according to the accidental and ever varying motions of the several objects whose equilibrium he is to preserve, which motions he must therefore constantly and closely watch. Now to do this, the closest attention, both of the eye and of the mind, to each of these instantaneous movements, is absolutely necessary, since the movements do not follow each other in any regular order, as do the notes of the musician, and cannot, therefore, by any association of ideas, be linked together, or laid up in the mind.
The Question undecided.—The question is a curious one, and with the arguments on either side, as now presented, I leave it to the reader's individual judgment and decision. Mr. Stewart is doubtless correct as to the rapidity of mental and muscular action. At the same time it seems to methere areactions, whatever may be true in the cases supposed, that are purelyautomaticandmechanical.
Whether we attend to more than one thing at once.—Analogous to the question already discussed, is the inquiry whether the mind ever attends or can attend to more than one thing at one and the same time; as when I read an author, my attention meanwhile being directed to some other object than the train of thought presented by the page before me, so that at the end of a paragraph or a chapter I find that I have no idea of what I have been reading, and yet I have followed with the eye, and perhaps pronounced aloud, every word and line of the entire passage. To do this must have required some attention. Have I then the power of attending to two things at once? So, when the musician carelessly strikes up a familiar air while engaged in animated conversation, and when the equilibrist balances both his own body upon the rope, and also a number of bodies upon different parts of his body, each movement of each requiring constant and instant attention, the same question arises.
Opinion of Mr. Stewart.—Mr. Stewart, in accordancewith the view already expressed of the rapidity of the mind's action, maintains that we do not under any circumstances attend at one and the same time to two objects of thought, but that the mind passes with such rapidity from one to another object in the cases supposed, that we are unconscious of the transition, and seem to ourselves to be attending to both objects at once.
Illustration of this View.—An illustration of this we find in the case of vision. Only one point of the surface of any external object is at any one instant in the direct line of vision, yet so rapidly does the eye pass from point to point, that we seem to perceive at a glance the whole surface.
How it is possible to compare different Objects.—It may be asked, How is it that we are able to compare one object with another, if we are unable to bring both before the mind at once? If, while I am thinking of A, I have no longer any thought whatever of B, how is it possible ever to bring together A and B before the mind so as to compare them?
The answer I conceive to be this, that the mind passes with such rapidity from the one to the other object, as to produce the same effect that would be produced were both objects actually before it at the same instant. The transition is not usually a matter of consciousness; yet if any one will observe closely the action of his own mind in the exercise of comparison, he will detect the passing of his thoughts back and forth from one object to the other many times before the conclusion is reached, and the comparison is complete.
CONCEPTION.
Character of this Power.—This term has been employed in various senses by different writers. It does not denote properly a distinct faculty of the mind. I conceive of a thing when I make it a distinct object of thought, when I apprehend it, when I construe it to myself as a possible thing, and as being thus and thus. This form of mental activity enters more or less into all our mental operations; it is involved in perception, memory, imagination, abstraction, judgment, reasoning, etc. For this reason it is not to be ranked as one of, and correlate with, these several specific faculties. Like the power of thought, and hardly even more limited than that, it underlies all the special faculties, and is essential to them all. Such at least is the ordinary acceptation of the term; and when we employ it to denote some specific form of mental activity, we employ it in a sense aside from its usual and established meaning.
Objects of Conception.—I conceive of an absent object of sight, as,e. g., the appearance of an absent friend, or of a foreign city, of the march of an army, or the eruption of a volcano. I conceive also of a mathematical truth, or a problem in astronomy. My conceptions are not limited to former perceptions or sensations, nor even to objects of sensible perception. They are not limited to material and sensible objects. They embrace the past and the future, the actual and the ideal, the sensible and the super-sensible.
Conceptions neither true nor false.—Our conceptions are neither true nor false, in themselves considered; they become so only when attended with some exercise of judgment or of belief. We conceive of a mountain of gold or ofglass, and this simple conception has nothing to do with truth or error. When we conceive of it, however, as actually existing, and in this or that place, or when we simply judge that such a mountain is somewhere to be found, then such judgment or belief is either true or false; but it is no longer simple conception.
Not always Possibilities; nor possible Things always conceivable.—Our conceptions are not always possibilities. We can conceive of some things not within the limits of possibility. On the other hand, not every thing possible even is conceivable. Existence without beginning or end is possible, but it is not in the power of the human mind, strictly speaking, to conceive of such a thing. I know that Deity thus exists. I understand what is meant by such a proposition, and I believe it. But I cannot construe it to myself as a definite intellection, an apprehension, as I can conceive of the existence of a city or a continent, or of the truth of a mathematical proposition.
The same may be said of the ideas of the infinite and the absolute. They are not properly within the limits of thought, of apprehension, to the human mind. Thought in its very nature imposes a limitation on the object which is thought of—fathoms it—passes around it with its measuring line—apprehends it: only so far as this is done is the thing actually thought; only so far as it can be done is the thing really thinkable. But the infinite, the unconditioned, the absolute, in their very nature unlimited, cannot be shut up thus within the narrow lines of human thought. They are inconceivable. They are not, however, contradictory to thought. They may be true; they are true and real, though we cannot properly conceive them.
The Inconceivable becomes Impossible, when.—Not every thing then which is inconceivable is impossible, nor, on the other hand, is every thing which is impossible inconceivable. The inconceivable is impossible, at least it can be known tobe so, only when it is either self-contradictory—as that a thing should be and not be at the same time—that a part is equal to the whole, etc.; or when it is contradictory of the laws of thought, as that two straight lines should enclose a space—that an event may occur without a cause—that space is not necessary to the existence of matter, or time to the succession of events. These things are unthinkable but they are more than that, contradictory of the established laws of thought; and they are impossible, because thus contradictory, and not merely because inconceivable. It is hardly true, as is sometimes affirmed, and as Dr. Wayland has stated, that our conceptions are the limits of possibility.
Mr. Stewart's use of the term Conception.—Mr. Stewart has employed the term Conception in a somewhat peculiar manner, and has assigned it a definite place among the faculties of the mind. He uses it to denote "that power of the mind which enables it to form a notion of an absent object of perception, or of a sensation which we have formerly felt." It is the office of this faculty "to present us with an exact transcript of what we have felt or perceived." In this respect it differs from imagination, which gives not an exact transcript, but one more or less altered or modified, combining our conceptions so as to form new results. It differs from memory in that it involves no idea of time, no recognition of the thing conceived, as a thing formerly perceived.
Objection to this use.—This use of the term is, on some accounts, objectionable. It is certainly not the ordinary sense of the word, but a departure from established usage. It is an arbitrary limitation of a word to denote a part only instead of the whole of that which it properly signifies There is no reason, in the nature of the case, why the notion we form of an absent object of perception, or of a sensation, should be called a conception, rather than ournotion of an abstract truth, a proposition in morals, or a mathematical problem. I am not aware that any special importance attaches to the former more than to the latter class of conceptions. Indeed, Sir W. Hamilton limits the term to the latter. But this again is not in accordance with established usage.
SENSE OR PERCEPTION BY THE SENSES.
§ I.—General Observations.
This Faculty the Foundation of our Knowledge.—Of the cognitive powers of the mind, the first to be noticed, according to the analysis and distribution already given, is the Presentative Power—the power of cognizing external objects through the senses. This claims our first attention, inasmuch as it lies, chronologically at least, at the foundation of all our cognitive powers, and in truth, of our entire mental activity. We can, perhaps, conceive of a being so constituted as to be independent of sense, and yet possess mental activity; and we can even conceive such a mind as taking cognizance, in some mysterious way, of objects external to itself. But not such a being is man—not such the nature of the human mind. Its activity is first awakened through sense; from sense it derives its knowledge of the external world, of whatever lies without and beyond the charmed circle of self; and whetherallour knowledge is, strictly speaking, derived from sense, or not—a question so much disputed, and which we will not here stay to discuss—there can be no doubt that the activity of sense, and the knowledge thus acquired, is at least the beginning and foundation of all our mental acquisitions. We are constantly receiving impressions from without through the senses. In this way the mind is first awakened to activity,and from this source we derive our knowledge of the external world.
General Character of this Faculty.—In its general character the faculty now under consideration, as the name indicates, ispresentativeandintuitive. It presents rather than represents objects, and what the mind thus perceives it perceives intuitively, rather than as the result of reflection. The knowledge which it gives isimmediateknowledge, the knowledge of that which is now and here present, in time and space.
Involves a twofold Element.—Looking more closely at the character of this faculty, we find it to involve a twofold element, which we cannot better indicate than by the termssubjectiveandobjective. There is, in the first place, the knowledge or consciousness of our own sentient organism as affected, and there is also the knowledge of something external to, and independent of the mind itself, or the me, as the producing cause of this affection of the organism. We know, by one and the same act, ourselves as affected, and the existence and presence of an external something affecting us. This presupposes, of course, the distinct independent existence of themeand thenot-me—of ourselves as thinking and sentient beings, and of objects external to ourselves, and material,—a distinction which lies at the foundation of all sense-perception. All perception by the senses involves, and presupposes, the existence of a sentient being capable of perceiving, and of an object capable of being perceived. It supposes, also, such a relation between the two, that the former is affected by the presence of the latter. From this results perception in its twofold aspect, or the knowledge, on the part of the sentient mind, at once of itself as affected, and of the object as affecting it. According as one or the other of these elements is more directly the object of attention, so the subjective and the objective character predominate in the act of perception. If the former, then we think chiefly of the me as affected,and are scarcely conscious of the external object as the source or the producing cause; if the latter, the reverse is true.
§ II—Analysis of the Perceptive Process.
Simple Sensation.—The nature of the presentative power may be better understood by observing closely the different steps of the process. As we come into contact with the external world, the first thing of which we are conscious, the first step in the process of cognition, is doubtless simple sensation. Something touches me, my bodily organism is thereby affected, and I am conscious, at once, of a certain feeling or sensation. I do not know as yet what has produced the sensation, or whether any thing produced it. I do not as yet recognize it as the result of an affection of the bodily organism, or even as pertaining to that organism in distinction from the spiritual principle. I am conscious only of a certain feeling. This is simplesensation—a purely subjective process.
Recognition of it as such.—We do not, however, stop here. The mind is at once aroused by the occurrence of the phenomenon supposed, the attention is directed to it. I cognize it as sensation, as feeling. If it be not the first instance of the kind in my experience, I distinguish it from other sensations which I have felt.
Distribution of it to the Parts affected.—More than this; I am conscious not only of the given sensation, but of its being an affection of my bodily organism, and of this or that part of the organism; I distinguish the body as the seat of the sensation, and this or that part of the body as the part affected. The organism as thus affected becomes itself an object of thought as distinct from the thinking mind that animates and pervades it. It becomes to me an externality, having extension and parts out of and distinct from each other. As thus viewed, and brought now for the first time under the eye of consciousness, it becomes knownto me as thenon-ego, still connected, however, by sensation with the ego, the sentient principle and as thus viewed, I become aware that the sensation which I feel is an affection of that organism, and of a certain portion of it, as the hand, or the foot. This cognizance of the sensation as such, as pertaining to the organism, and to this or that part of the same, and the consequent cognizance of the organism as such, as distinct from the sentient mind, and as thus and thus affected, is no longer simplesensation, it isperception.
Cognition of something external to the Organism itself.—This is the most simple form of immediate perception. The process does not, however, necessarily stop here. I am conscious not only of this or that part of my organism as affected, but of something external to the organism itself, in contact with and affecting it. This organism with which I find myself connected, the seat of sensation, the object of perception, is capable of self-movement in obedience to my volitions. I am conscious of the effort to move my person, and conscious also of being resisted in those movements by something external in contact with my organism. This yet unknown something becomes now the object of attention and perception—this new phenomenon—resistance, something resisting. To perceive that I am resisted, is to perceive that something resists, and to perceive this is to perceive the object itself which offers such resistance. I may not know every thing pertaining to it, what sort of thing it may be, but I know this respecting it, that it exists, that it is external to my organism, that it resists my movements. Thus the outer world becomes directly an object of perception—passes under the immediate eye of consciousness.
In what Sense these several Steps distinct.—In the preceding analysis, in order more clearly to illustrate the nature of the process, we have regarded the act of perception as broken into several distinct parts, or steps of progress. This, however, is not strictly correct as regards the psychology of the matter. Logically, we may distinguish the simplesensation as mere feeling, from the reference of the same to this or that part of the bodily organism as affected, and each of these again, from the cognizance of the external object, which by contact or resistance produces the sensation. Chronologically, the act is one and indivisible. The sensation and the perception are synchronous. We cannot separate the act of sense-perception into the consciousness of a sensation, the consciousness of the bodily organism as affected by that sensation, and the consciousness of an external something as the proximate cause of that affection. To experience a sensation, is to experience it as here or there in the sentient organism, and to perceive contact or resistance, is to perceive something in contact or resisting. There may, however, be sensation without cognizance of the external producing cause.
Restricted Sense of the term Perception.—According to the view now advanced, perception isimmediate; not a matter of inference, not a roundabout reflective process. It is a cognizance direct and intuitive of the bodily organization as thus and thus affected, and of an external something in correlation with it, affecting and limiting that organism in its movements.
Usually, however, a wider range has been given to the term, and the faculty thereby denoted. It has been made to comprehend any mental process by which we refer a specific sensation to something external as its producing cause. It is thus employed by Reid and Stewart, and such has been in fact the prevalent use of the term. According to this, when we experience the sensation of fragrance, and refer that sensation to the presence of a rose, or the sensation of sound, and refer it to the stroke of a bell, or a passing carriage, we exercise the faculty of perception. Evidently, however, our knowledge in these cases is merely a matter of inference, of judgment, not of immediate direct perception, not in fact of perception at all. All that we properly perceive in such a case, all that we are directly conscious ofis the fragrance or the sound. That these are produced by the rose and the bell is not perceived, but onlyconceived, inferred—known, if at all, only by the aid of previous experience.
Sensation as distinguished from Perception.—According to the view now presented,sensation, as distinguished fromperception, is thesimple feelingwhich results from a certain affection of the organism. It is known to us merely as feeling. Perception takes cognizance of the feelingas an affection of the organism, and also of the organism as thus affected, and consequently as external to the me, extended, having parts, etc. It apprehends also objects external to the organism itself limiting and affecting its movements. Sensation is the indispensable condition of perception. If there were no sensation, there would be no perception. The one does not precede, however, and the other follow in order of time, but the one being given, the other is given along with it. The two do not, however, coexist in equal strength, but in the relation, as stated by Hamilton, ofinverse ratio; that is, beyond a certain point, the stronger the sensation, the weaker the perception, andvice versâ.
Sensation as an Affection of the Mind.—It has been common to speak of sensation as lying wholly in the mind. Primarily, however, it is an affection of the nervous organism, and through that organism, as thus affected, an impression is made on the mind. If it were not for the mind present with the organism, and susceptible of impression from it, and thus cognizant of changes in it, the same changes might be produced in the organism as now, but we should be entirely unconscious of and insensible to them. In certain states of the system this actually happens, as in sound sleep, the magnetic state, the state produced by certain medicinal agents as ether, chloroform, opium, and the intoxicating drugs of the East. In those cases, the connection between the mind and the nervous organism seems to be in some manner interrupted or suspended, andconsequently there is for the time no sensation. The nerves may be irritated, divided even, and still no pain is felt.
It is not true, however, that the sensation is wholly in the mind. It is in the living animated organism, as pervaded by the mind or spiritual principle, mysteriously present in every part of that organism, and cognizant of its changes; and neither the body alone, nor the mind alone, can be said to possess this faculty, but the two united in that complex mysterious unity which constitutes our present being.
§ III.—Analysis and Classification of the Qualities of Bodies.
Difference of Qualities.—The qualities of bodies as known to us through sensation and perception are many and various. On examination, a difference strikes us as existing among these qualities, which admits of being made the basis of classification. Some of them are qualities which strike us at once as essential to the very existence of matter, at least in our notion of it, so that we cannot in thought divest it of these qualities, and still retain our conception of matter. Others are not of this nature. Extension, divisibility, size, figure, situation, and some others, are of the former class. If matter exists at all, it must, according to our own conceptions, possess these qualities. We cannot think them away from it, and leave matter still existing. But we can conceive of matter as destitute of color, flavor, savor, heat, cold, weight, sound, hardness, etc. These are contingent and accidental properties not necessary to its existence.
How named and distinguished.—Philosophers have called the former classprimary, the lattersecondaryqualities. The former are knownà priori, the latter by experience. The former are known as qualities, in themselves, the latter only through the affections of our senses.
The primary qualities then have these characteristics:
1. They are essential to the very existence of matter, at least in our conception.
2. They are to be knownà priori.
3. They are known as such, or in themselves.
The secondary, on the contrary, are:
1. Accidental, not essential to the notion of matter.
2. To be known only by experience.
3. To be learned only through the affection of the senses.
Further Division of secondary Qualities.—A further division, however, is capable of being made. The secondary qualities, as now defined, comprise, in reality, two classes. There are some, which, while known to us only through the senses, have still an existence as qualities of external objects, independent of our senses. As such they are objects of direct perception. Others, again, are known, not as qualities of bodies, but only as affections of sense, not as objective, but only as subjective, not as perceptions, but only as sensations. Thus I distinguish the smell, the taste, and the color of an orange. What I distinguish, however, is after all only certain sensations, certain affections of my own organism. What may be the peculiar properties or qualities in the object itself which are the exciting cause of these sensations in me, I know not. My perception does not extend to them at all. It is quite otherwise with the qualities of weight, hardness, compressibility, fluidity, elasticity, and others of that class. They are objects of perception, and not of sensation merely.
These Classes, how distinguished.—The class first named, are qualities of bodies as related to other bodies. The other class are qualities of bodies as related only to our nervous organization. The former all relate to bodies as occupying and moving inspace, and come under the category ofresistance. The latter relate to bodies only as capable of producing certain sensations in us. We may call the formermechanical, the latterphysiological.
Connection of Sensation with the external Object.—From long habit of connecting the sensation with the external body which produces it, we find it difficult topersuade ourselves that taste and smell are mere affections of our senses, or that color is really and simply an affection of the optic nerve of the beholder, and that what is actually perceived in these instances is not properly a quality of the external object. A little reflection, however, will convince us that all which comes to our knowledge in these cases, all that we are properly cognizant of, is the affection of our own nervous organism, and that whatever may be the nature of the qualities in the object which are the producing cause of these sensations in us, they are to us occult and wholly unknown.
Power of producing these Sensations.—It is not to be denied, of course, that there is in external objects the power of producing these sensations in us, under given circumstances; but to what that power is owing, in what peculiarity of constitution or condition it consists, we know not. We have but one name, moreover, for the power of producing, and the effect produced. Thus the color, taste, smell, etc., of an object may denote either the sensation in us, or the unknown property of matter by virtue of which the sensation is awakened. It is only in the sense last mentioned, that the qualities under consideration may properly be called qualities of bodies.
Enumeration of the several Qualities as now classed.—According to the classification now made, the qualities of bodies may be thus enumerated.
I.Primary.—Extension, divisibility, size, density, figure, absolute incompressibility, mobility, situation.
II.Secondary.—A.Objective, ormechanical—as heavy or light, hard or soft, firm or fluid, rough or smooth, compressible or incompressible, resilient or irresilient, and any other qualities of this general nature resulting from attraction, repulsion, etc.
B.Subjectiveorphysiological—as color, sound, flavor, savor, temperature, tactual sensation, and certain other affections of the senses of this nature.
§ IV.—Organs of Sense.—Analysis of their Several Functions
Number of the Senses.—The different senses are usually reckoned as five in number. They may all be regarded, however, as modifications of one general sense, that of touch—or, in other words, the susceptibility of the nervous system to be excited by foreign substances brought into contact with it. This is the essential condition of sensation in any case, and the several senses, so called, are but so many variations in the mode of manifesting this excitability. There is a reason, nevertheless, for assigning five of these modifications and no more, and that is, that the anatomical structure indicates either a distinct organ, as the ear, the eye, etc., or at least a distinct branch of the nervous apparatus, as in the case of smell and taste, while the whole nervous expansion as spread out over the surface of the body contributes to the general sense of touch.
The Senses related to each other.—Distinct Office of each.—It is evident enough that these several senses sustain a certain relation to each other. They are so many and no more, not merely by accident; not merely because so many could find room in the bodily organization; not merely because it might be convenient to have so many. Let us look at the office performed by each, and we shall see that while each has its distinct function, not interchangeable with that of any other, it is a function more or less necessary to the animal economy. Remembering that the design and use of the several senses is to put us in possession of data, by means of which, directly or indirectly, we may gain correct knowledge of the external world, let us suppose the inquiry to be raised, What senses ought man to have for this purpose? What does he need, the material universe remaining what it is?
Function of the Sense of Touch.—Things exist about us in space, having certain properties and relations. We need a sense then, first and chiefly, that shall acquaint uswith objects thus existing, taking cognizance of what lies immediately about us in space. This we have in the general sense of touch, making us acquainted with certain objective or mechanical qualities of external objects.
This Sense, how limited.—This, however, avails only for objects within a short distance, and capable of being brought into contact. It operates also synthetically and slowly, part after part of the object being given as we are brought into contact with different portions of it successively until the process is so far complete that, from the ensemble of these different parts, our understanding can construct the whole.
Possibility of a Sense that shall meet these Limitations.—We can conceive of a sense that should differ in both these respects—that should take cognizance of distant objects, not capable perhaps of being brought into contact—and that should also operate analytically, or work from a given whole to the parts, and not from the parts to a whole, thus giving us possession at once of a complete object or series of objects. Such a sense, it is easy to see, would possess decided advantages, and in connection with the one already considered, would seem to bring within the sphere of our cognizance almost the complete range of external nature. This we have, and this exactly, in the sense ofvision. It takes in objects at a distance, and takes in the whole at a glance.
This new Sense still limited.—This new sense, however convenient and useful as it is, has evidently its limitations. It is available only through a given medium, the light. Strictly speaking, it is the light only that we see, and not the distant object; that is known indirectly by means of the light that variously modified, travels from it to the eye. When this fails, as it does during several hours of the twenty-four, or when it is intercepted by objects coming between and shutting out the forms on which the eye seeks in vain to rest, then our knowledge from this source is cut off.
Still another Sense desirable.—Under these circumstances, might it not be well, were there given an additional sense, of the same general nature and design, but operating through a different medium, sure to be present wherever animal life exists, so that even in the darkness of the night, or the gloom of the dungeon, we might still have means of knowing something of the surrounding objects. And what of this medium, or avenue of sense, were of such a nature as to be capable of modification, and control, to some extent, on our part, and at our pleasure, so as to form a means of voluntary communication with our fellow-beings. Would not such an arrangement be of great service? Exactly these things are wanted; exactly these wants are met, and these objects accomplished, by a new sense answering to these conditions—the sense ofhearing—the cognizance of sound. This we produce when we please by the spoken word, the vocal utterance, whether of speech, or musical note, or inarticulate cry, varied as we please, high, low, loud, soft—a complete alphabet of expression, conveying thus by signals, at once rapid and significant, the varying moods and phases of our inner life to other beings that had else been strangers, for the most part, to the thoughts and feelings which agitate our bosoms.
Senses for another Class of Qualities.—The senses, as thus far analyzed, have reference primarily to the number magnitude, and distance of objects as occupying space—to quantities rather than qualities. Were it possible now to add to these a sense, or senses that should take cognizance of quality, as well as existence and quantity—that should detect, to some extent at least, thechemicalproperties of bodies as connected especially with the functions of respiration and nutrition—the list of senses would seem to be complete. This addition is made, this knowledge given, in the senses ofsmellandtaste.
Possibility of additional Senses.—To those already named, other senses might doubtless have been added bythe Creator, which would have revealed, it may be, properties of matter of which we have now no conception. It is not to be supposed that we know every thing respecting the nature and qualities of even the most familiar and common objects. Many things there may be, actual, real, in the world about us, of which we know nothing, because they come not within the range of any of our senses. But all that is essential to life, and happiness, and highest welfare is doubtless imparted by the present arrangement; and when closely studied, no one of these senses will be found superfluous, no one overlapping the province of another, but working each its specific end, and all in harmony.
The proper Office of Psychology in respect to the Senses.—It is the province of the anatomist and the physiologist to explain the mechanical structure of the several organs of sense, and their value as parts of the physical system. The psychologist has to do with them only as instruments of the mind, and it is for him to show their connection and proper office as such. This has been attempted in the preceding analysis.
The kind of Knowledge afforded by the Senses.—It is to be noticed, in addition, that with the exception of the tactual sense, and possibly of sight, these senses give us no direct, immediate knowledge of external things. They simply furnish data, signs, intimations, by the help of which the understanding forms its conclusions of the world with out. They are thereceivingagents of the mind. This is, in fact, the chief office of sense, to receive through its various avenues the materials from which the understanding shall frame conceptions of things without; to convey, as it were, a series of telegraphic despatches along those curious and slender filaments that compose the nervous organization, by means of which the soul, keeping her hidden seat and chamber within, may receive communication from the distant provinces of her empire. These signs the understanding interprets; and in so far as this is the true nature of the process, it is not a process of immediate and proper perception. I hear, for example, a noise. All that I really perceive in this case is the sensation of sound. I refer it, however, to an external cause, to a carriage passing in the street. I specify, moreover, the kind of carriage, perhaps a coach, or a wagon with iron axles. I have observed, have learned by experience, that sounds of this nature are produced in this way, that is, by carriages passing, and by such carriages. Hence I judge that the sound which I now hear is produced in the same way. It is aninference, a conception merely. All that sense does is to receive and transmit the sign, which the understanding interprets by the aid of former experience. And the same is true of the other senses, with the exceptions named.
Not therefore of little Value.—We are not to infer, however, that these senses are on this account of no special value or importance to us. They do precisely what is needed. They put us in possession of just the data wanted in order to the necessary information concerning external things. It is only the theorist who undervalues the senses, and he only in his closet. No man, in the full possession of his reason, and his right mind, can go forth into this fair and goodly world, and not thank God for every one of those senses—sight, hearing, taste, touch, and smell. Their true and full value, however, we never learn till we come to be deprived of their use; till with Milton we exclaim,