He regards mental phenomena and physical phenomena as links in the one chain of causes and effects. Shall he hold that certain mental links are "free-will" links, that they are wholly unaccountable? If he does, all that has been said above about the "free-willist" applies to him. He believes in a disorderly world, and he should accept the consequences of his doctrine.
47. THE PHYSICAL WORLD AND THE MORAL WORLD.--I have said a little way back that, when we think of bodies as having minds, we are introduced to a world of distinctions which have no place in the realm of the merely physical. One of the objections made to the orderly world of the parallelist was that in it there is no room for the activity of minds. Before we pass judgment on this matter, we should try to get some clear notion of what we may mean by the word "activity." The science of ethics must go by the board, if we cannot think of men as _doing_ anything, as acting rightly or acting wrongly.
Let us conceive a billiard ball in motion to come into collision with one at rest. We commonly speak of the first ball as active, and of the second as the passive subject upon which it exercises its activity. Are we justified in thus speaking?
In one sense, of course, we are. As I have several times had occasion to remark, we are, in common life, justified in using words rather loosely, provided that it is convenient to do so, and that it does not give rise to misunderstandings.
But, in a stricter sense, we are not justified in thus speaking, for in doing so we are carrying over into the sphere of the merely physical a distinction which does not properly belong there, but has its place in another realm. The student of mechanics tells us that the second ball has affected the first quite as much as the first has affected the second. We cannot simply regard the first as cause and the second as effect, nor may we regard the motion of the first as cause and the subsequent motion of the second as its effect alone. _The whole situation at the one instant_--both balls, their relative positions and their motion and rest--must be taken as the cause of _the whole situation at the next instant_, and in this whole situation the condition of the second ball has its place as well as that of the first.
If, then, we insist that to have causal efficiency is the same thing as to be active, we should also admit that the second ball was active, and quite as active as the first. It has certainly had as much to do with the total result. But it offends us to speak of it in this way. We prefer to say that the first was active and the second was acted upon. What is the source of this distinction?
Its original source is to be found in the judgments we pass upon conscious beings, bodies with minds; and it could never have been drawn if men had not taken into consideration the relations of minds to the changes in the physical world. As carried over to inanimate things it is a transferred distinction; and its transference to this field is not strictly justifiable, as has been indicated above.
I must make this clear by an illustration. I hurry along a street towards the university, because the hour for my lecture is approaching. I am struck down by a falling tile. In my advance up the street I am regarded as active; in my fall to the ground I am regarded as passive.
Now, looking at both occurrences from the purely physical point of view, we have nothing before us but a series of changes in the space relations of certain masses of matter; and in all those changes both my body and its environment are concerned. As I advance, my body cannot be regarded as the sole cause of the changes which are taking place. My progress would be impossible without the aid of the ground upon which I tread. Nor can I accuse the tile of being the sole cause of my demolition. Had I not been what I was and where I was, the tile would have fallen in vain. I must be regarded as a concurrent cause of my own disaster, and my unhappy state is attributable to me as truly as it is to the tile.
Why, then, am I in the one case regarded as active and in the other as passive? In each case I am a cause of the result. How does it happen that, in the first instance, I seem to most men to be _the_ cause, and in the second to be not a cause at all? The rapidity of my motion in the first instance cannot account for this judgment. He who rides in the police van and he who is thrown from the car of a balloon may move with great rapidity and yet be regarded as passive.
Men speak as they do because they are not content to point out the physical antecedents of this and that occurrence and stop with that. They recognize that, between my advance up the street and my fall to the ground there is one very important difference. In the first case what is happening _may be referred to an idea in my mind_. Were the idea not there, I should not do what I am doing. In the second case, what has happened _cannot be referred to an idea in my mind_.
Here we have come to the recognition that there are such things as _purposes_ and _ends_; that an idea and some change in the external world may be related as _plan_ and _accomplishment_. In other words, we have been brought face to face with what has been given the somewhat misleading name of _final cause_. In so far as that in the bringing about of which I have had a share is my _end_, I am _active_; in so far as it is not my end, but comes upon me as something not planned, I am _passive_. The enormous importance of the distinction may readily be seen; it is only in so far as I am a creature who can have purposes, that _desire_ and _will_, _foresight_ and _prudence_, _right_ and _wrong_, can have a significance for me.
I have dwelt upon the meaning of the words "activity" and "passivity," and have been at pains to distinguish them from cause and effect, because the two pairs of terms have often been confounded with each other, and this confusion has given rise to a peculiarly unfortunate error. It is this error that lies at the foundation of the objection referred to at the beginning of this section.
We have seen that certain men of science are inclined to look upon the physical world as a great system, all the changes in which may be accounted for by an appeal to physical causes. And we have seen that the parallelist regards ideas, not as links in this chain, but as parallel with physical changes.
It is argued by some that, if this is a true view of things, we must embrace the conclusion that _the mind cannot be active at all_, that it can _accomplish nothing_. We must look upon the mind as an "epiphenomenon," a useless decoration; and must regard man as "a physical automaton with parallel psychical states."
Such abuse of one's fellow-man seems unchristian, and it is wholly uncalled for on any hypothesis. Our first answer to it is that it seems to be sufficiently refuted by the experiences of common life. We have abundant evidence that men's minds do count for something. I conclude that I want a coat, and I order one of my tailor; he believes that I will pay for it, he wants the money, and he makes the coat; his man desires to earn his wages and he delivers it. If I had not wanted the coat, if the tailor had not wanted my money, if the man had not wanted to earn his wages, the end would not have been attained. No philosopher has the right to deny these facts.
Ah! but, it may be answered, these three "wants" are not supposed to be the _causes_ of the motions in matter which result in my appearing well-dressed on Sunday. They are only _concomitant phenomena_.
To this I reply: What of that? We must not forget what is meant by such concomitance (section 39). We are dealing with a fixed and necessary relation, not with an accidental one. If these "wants" had been lacking, there would have been no coat. So my second answer to the objector is, that, on the hypothesis of the parallelist, the relations between mental phenomena and physical phenomena are just as dependable as that relation between physical phenomena which we call that of cause and effect. Moreover, since activity and causality are not the same thing, there is no ground for asserting that the mind cannot be active, merely because it is not material and, hence, cannot be, strictly speaking, a cause of motions in matter.
The plain man is entirely in the right in thinking that minds are active. The truth is that _nothing can be active except as it has a mind_. The relation of purpose and end is the one we have in view when we speak of the activity of minds.
It is, thus, highly unjust to a man to tell him that he is "a physical automaton with parallel psychical states," and that he is wound up by putting food into his mouth. He who hears this may be excused if he feels it his duty to emit steam, walk with a jerk, and repudiate all responsibility for his actions. Creatures that think, form plans, and _act_, are not what we call automata. It is an abuse of language to call them such, and it misleads us into looking upon them as we have no right to look upon them. If men really were automata in the proper sense of the word, we could not look upon them as wise or unwise, good or bad; in short, the whole world of moral distinctions would vanish.
Perhaps, in spite of all that has been said in this and in the preceding section, some will feel a certain repugnance to being assigned a place in a world as orderly as our world is in this chapter conceived to be--a world in which every phenomenon, whether physical or mental, has its definite place, and all are subject to law. But I suppose our content or discontent will not be independent of our conception of what sort of a world we conceive ourselves to be inhabiting.
If we conclude that we are in a world in which God is revealed, if the orderliness of it is but another name for Divine Providence, we can scarcely feel the same as we would if we discovered in the world nothing of the Divine. I have in the last few pages been discussing the doctrine of purposes and ends, teleology, but I have said nothing of the significance of that doctrine for Theism. The reader can easily see that it lies at the very foundation of our belief in God. The only arguments for theism that have had much weight with mankind have been those which have maintained there are revealed in the world generally evidences of a plan and purpose at least analogous to what we discover when we scrutinize the actions of our fellow-man. Such arguments are not at the mercy of either interactionist or parallelist. On either hypothesis they stand unshaken.
With this brief survey of some of the most interesting problems that confront the philosopher, I must content myself here. Now let us turn and see how some of the fundamental problems treated in previous chapters have been approached by men belonging to certain well-recognized schools of thought.
And since it is peculiarly true in philosophy that, to understand the present, one must know something of the past, we shall begin by taking a look at the historical background of the types of philosophical doctrine to which reference is constantly made in the books and journals of the day.
[1] Ostwald, "Vorlesungen uber Naturphilosophie," s. 396. Leipzig, 1902.
IV. SOME TYPES OF PHILOSOPHICAL THEORY
CHAPTER XII
THEIR HISTORICAL BACKGROUND
48. THE DOCTRINE OF REPRESENTATIVE PERCEPTION.--We have seen in Chapter II that it seems to the plain man abundantly evident that he really is surrounded by material things and that he directly perceives such things. This has always been the opinion of the plain man and it seems probable that it always will be. It is only when he begins to reflect upon things and upon his knowledge of them that it occurs to him to call it in question.
Very early in the history of speculative thought it occurred to men, however, to ask how it is that we know things, and whether we are sure we do know them. The problems of reflection started into life, and various solutions were suggested. To tell over the whole list would take us far afield, and we need not, for the purpose we have in view, go back farther than Descartes, with whom philosophy took a relatively new start, and may be said to have become, in spirit and method, at least, modern.
I have said (section 31) that Descartes (1596-1650) was fairly well acquainted with the functioning of the nervous system, and has much to say of the messages which pass along the nerves to the brain. The same sort of reasoning that leads the modern psychologist to maintain that we know only so much of the external world as is reflected in our sensations led him to maintain that the mind is directly aware of the ideas through which an external world is represented, but can know the world itself only indirectly and through these ideas.
Descartes was put to sore straits to prove the existence of an external world, when he had once thus placed it at one remove from us. If we accept his doctrine, we seem to be shut up within the circle of our ideas, and can find no door that will lead us to a world outside. The question will keep coming back: How do we _know_ that, corresponding to our ideas, there are material things, if we have never perceived, in any single instance, a material thing? And the doubt here suggested may be reinforced by the reflection that the very expression "a material thing" ought to be meaningless to a man who, having never had experience of one, is compelled to represent it by the aid of something so different from it as ideas are supposed to be. Can material things really be to such a creature anything more than some complex of ideas?
The difficulties presented by any philosophical doctrine are not always evident at once. Descartes made no scruple of accepting the existence of an external world, and his example has been followed by a very large number of those who agree with his initial assumption that the mind knows immediately only its own ideas.
Preeminent among such we must regard John Locke, the English philosopher (1632-1704), whose classic work, "An Essay concerning Human Understanding," should not be wholly unknown to any one who pretends to an interest in the English literature.
Admirably does Locke represent the position of what very many have regarded as the prudent and sensible man,--the man who recognizes that ideas are not external things, and that things must be known through ideas, and yet holds on to the existence of a material world which we assuredly know.
He recognizes, it is true, that some one may find a possible opening for the expression of a doubt, but he regards the doubt as gratuitous; "I think nobody can, in earnest, be so skeptical as to be uncertain of the existence of those things which he sees and feels." As we have seen (section 12), he meets the doubt with a jest.
Nevertheless, those who read with attention Locke's admirably clear pages must notice that he does not succeed in really setting to rest the doubt that has suggested itself. It becomes clear that Locke felt so sure of the existence of the external world because he now and then slipped into the inconsistent doctrine that he perceived it immediately, and not merely through his ideas. Are those things "which he sees and feels" _external_ things? Does he see and feel them directly, or must he infer from his ideas that he sees and feels them? If the latter, why may one not still doubt? Evidently the appeal is to a direct experience of material things, and Locke has forgotten that he must be a Lockian.
"I have often remarked, in many instances," writes Descartes, "that there is a great difference between an object and its idea." How could the man possibly have remarked this, when he had never in his life perceived the object corresponding to any idea, but had been altogether shut up to ideas? "Thus I see, whilst I write this," says Locke,[1] "I can change the appearance of the paper, and by designing the letters tell beforehand what new idea it shall exhibit the very next moment, by barely drawing my pen over it, which will neither appear (let me fancy as much as I will), if my hand stands still, or though I move my pen, if my eyes be shut; nor, when those characters are once made on the paper, can I choose afterward but see them as they are; that is, have the ideas of such letters as I have made. Whence it is manifest, that they are not barely the sport and play of my own imagination, when I find that the characters that were made at the pleasure of my own thought do not obey them; nor yet cease to be, whenever I shall fancy it; but continue to affect the senses constantly and regularly, according to the figures I made them."
Locke is as bad as Descartes. Evidently he regards himself as able to turn to the external world and perceive the relation that things hold to ideas. Such an inconsistency may escape the writer who has been guilty of it, but it is not likely to escape the notice of all those who come after him. Some one is sure to draw the consequences of a doctrine more rigorously, and to come to conclusions, it may be, very unpalatable to the man who propounded the doctrine in the first instance.
The type of doctrine represented by Descartes and Locke is that of _Representative Perception_. It holds that we know real external things only through their mental representatives. It has also been called _Hypothetical Realism_, because it accepts the existence of a real world, but bases our knowledge of it upon an inference from our sensations or ideas.
49. THE STEP TO IDEALISM.--The admirable clearness with which Locke writes makes it the easier for his reader to detect the untenability of his position. He uses simple language, and he never takes refuge in vague and ambiguous phrases. When he tells us that the mind is wholly shut up to its ideas, and then later assumes that it is not shut up to its ideas, but can perceive external things, we see plainly that there must be a blunder somewhere.
George Berkeley (1684-1753), Bishop of Cloyne, followed out more rigorously the consequences to be deduced from the assumption that all our direct knowledge is of ideas; and in a youthful work of the highest genius entitled "The Principles of Human Knowledge," he maintained that there is no material world at all.
When we examine with care the objects of sense, the "things" which present themselves to us, he argues, we find that they resolve themselves into sensations, or "ideas of sense." What can we mean by the word "apple," if we do not mean the group of experiences in which alone an apple is presented to us? The word is nothing else than a name for this group as a group. Take away the color, the hardness, the odor, the taste; what have we left? And color, hardness, odor, taste, and anything else that may be referred to any object as a quality, can exist, he claims, only in a perceiving mind; for such things are nothing else than sensations, and how can there be an unperceived sensation?
The things which we perceive, then, he calls complexes of ideas. Have we any reason to believe that these ideas, which exist in the mind, are to be accepted as representatives of things of a different kind, which are not mental at all? Not a shadow of a reason, says Berkeley; there is simply no basis for inference at all, and we cannot even make clear what it is that we are setting out to infer under the name of matter. We need not, therefore, grieve over the loss of the material world, for we have suffered no loss; one cannot lose what one has never had.
Thus, the objects of human knowledge, the only things of which it means anything to speak, are: (1) Ideas of Sense; (2) Ideas of Memory and Imagination; (3) The Passions and Operations of the Mind; and (4) The Self that perceives all These.
From Locke's position to that of Berkeley was a bold step, and it was much criticised, as well it might be. It was felt then, as it has been felt by many down to our own time, that, when we discard an external world distinct from our ideas, and admit only the world revealed in our ideas, we really do lose.
It is legitimate to criticise Berkeley, but it is not legitimate to misunderstand him; and yet the history of his doctrine may almost be called a chronicle of misconceptions. It has been assumed that he drew no distinction between real things and imaginary things, that he made the world no better than a dream, etc. Arbuthnot, Swift, and a host of the greater and lesser lights in literature, from his time to ours, have made merry over the supposed unrealities in the midst of which the Berkeleian must live.
But it should be remembered that Berkeley tried hard to do full justice to the world of things in which we actually find ourselves; not a hypothetical, inferred, unperceived world, but the world of the things we actually perceive. He distinguished carefully between what is real and what is merely imaginary, though he called both "ideas"; and he recognized something like a system of nature. And, by the argument from analogy which we have already examined (section 41), he inferred the existence of other finite minds and of a Divine Mind.
But just as John Locke had not completely thought out the consequences which might be deduced from his own doctrines, so Berkeley left, in his turn, an opening for a successor. It was possible for that acutest of analysts, David Hume (1711-1776), to treat him somewhat as he had treated Locke.
Among the objects of human knowledge Berkeley had included the _self_ that perceives things. He never succeeded in making at all clear what he meant by this object; but he regarded it as a substance, and believed it to be a cause of changes in ideas, and quite different in its nature from all the ideas attributed to it. But Hume maintained that when he tried to get a good look at this self, to catch it, so to speak, and to hold it up to inspection, he could not find anything whatever save perceptions, memories, and other things of that kind. The self is, he said, "but a bundle or collection of different perceptions which succeed each other with inconceivable rapidity, and are in a perpetual flux and movement."
As for the objects of sense, our own bodies, the chairs upon which we sit, the tables at which we write, and all the rest--these, argues Hume, we are impelled by nature to think of as existing continuously, but we have no evidence whatever to prove that they do thus exist. Are not the objects of sense, after all, only sensations or impressions? Do we not experience these sensations or impressions interruptedly? Who sees or feels a table continuously day after day? If the table is but a name for the experiences in question, if we have no right to infer material things behind and distinct from such experiences, are we not forced to conclude that the existence of the things that we see and feel is an interrupted one?
Hume certainly succeeded in raising more questions than he succeeded in answering. We are compelled to admire the wonderful clearness and simplicity of his style, and the acuteness of his intellect, in every chapter. But we cannot help feeling that he does injustice to the world in which we live, even when we cannot quite see what is wrong. Does it not seem certain to science and to common sense that there is an order of nature in some sense independent of our perceptions, so that objects may be assumed to exist whether we do or do not perceive them?
When we read Hume we have a sense that we are robbed of our real external world; and his account of the mind makes us feel as a badly tied sheaf of wheat may be conceived to feel--in danger of falling apart at any moment. Berkeley we unhesitatingly call an _Idealist_, but whether we shall apply the name to Hume depends upon the extension we are willing to give to it. His world is a world of what we may broadly call _ideas_; but the tendencies of his philosophy have led some to call it a _Skepticism_.
50. THE REVOLT OF "COMMON SENSE."--Hume's reasonings were too important to be ignored, and his conclusions too unpalatable to satisfy those who came after him. It seemed necessary to seek a way of escape out of this world of mere ideas, which appeared to be so unsatisfactory a world. One of the most famous of such attempts was that made by the Scotchman Thomas Reid (1710-1796).
At one time Reid regarded himself as the disciple of Berkeley, but the consequences which Hume deduced from the principles laid down by the former led Reid to feel that he must build upon some wholly different foundation. He came to the conclusion that the line of philosophers from Descartes to Hume had made one capital error in assuming "that nothing is perceived but what is in the mind that perceives it."
Once admit, says Reid, that the mind perceives nothing save ideas, and we must also admit that it is impossible to prove the existence either of an external world or of a mind different from "a bundle of perceptions." Hence, Reid maintains that we perceive--not infer, but perceive--_things_ external to the mind. He writes:[2]--
"Let a man press his hand against the table--_he feels it hard_. But what is the meaning of this? The meaning undoubtedly is, that he hath a certain feeling of touch, from which he concludes, without any reasoning, or comparing ideas, that there is something external really existing, whose parts stick so firmly together that they cannot be displaced without considerable force.
"There is here a feeling, and a conclusion drawn from it, or some way suggested by it. In order to compare these, we must view them separately, and then consider by what tie they are connected, and wherein they resemble one another. The hardness of the table is the conclusion, the feeling is the medium by which we are led to that conclusion. Let a man attend distinctly to this medium, and to the conclusion, and he will perceive them to be as unlike as any two things in nature. The one is a sensation of the mind, which can have no existence but in a sentient being; nor can it exist one moment longer than it is felt; the other is in the table, and we conclude, without any difficulty, that it was in the table before it was felt, and continues after the feeling is over. The one implies no kind of extension, nor parts, nor cohesion; the other implies all these. Both, indeed, admit of degrees, and the feeling, beyond a certain degree, is a species of pain; but adamantine hardness does not imply the least pain.
"And as the feeling hath no similitude to hardness, so neither can our reason perceive the least tie or connection between them; nor will the logician ever be able to show a reason why we should conclude hardness from this feeling, rather than softness, or any other quality whatsoever. But, in reality, all mankind are led by their constitution to conclude hardness from this feeling."
It is well worth while to read this extract several times, and to ask oneself what Reid meant to say, and what he actually said. He is objecting, be it remembered, to the doctrine that the mind perceives immediately only its own ideas or sensations and must infer all else. His contention is that we _perceive_ external things.
Does he say this? He says that we have feelings of touch _from which we conclude_ that there is something external; that there is a feeling, "_and a conclusion drawn from it, or some way suggested by it_;" that "the hardness of the table is the _conclusion_, and the feeling is the _medium_ by which we are _led to the conclusion_."
Could Descartes or Locke have more plainly supported the doctrine of representative perception? How could Reid imagine he was combatting that doctrine when he wrote thus? The point in which he differs from them is this: he maintains that we draw the conclusion in question without any reasoning, and, indeed, in the absence of any conceivable reason why we should draw it. We do it instinctively; we are led by the constitution of our nature.
In effect Reid says to us: When you lay your hand on the table, you have a sensation, it is true, but you also know the table is hard. How do you know it? I cannot tell you; you simply know it, and cannot help knowing it; and that is the end of the matter.
Reid's doctrine was not without its effect upon other philosophers. Among them we must place Sir William Hamilton (1788-1856), whose writings had no little influence upon British philosophy in the last half of the last century.
Hamilton complained that Reid did not succeed in being a very good _Natural Realist_, and that he slipped unconsciously into the position he was concerned to condemn. Sir William tried to eliminate this error, but the careful reader of his works will find to his amusement that this learned author gets his feet upon the same slippery descent. And much the same thing may be said of the doctrine of Herbert Spencer (1820-1903), who claims that, when we have a sensation, we know directly that there is an external thing, and then manages to sublimate that external thing into an Unknowable, which we not only do not know directly, but even do not know at all.
All of these men were anxious to avoid what they regarded as the perils of Idealism, and yet they seem quite unable to retain a foothold upon the position which they consider the safer one.
Reid called his doctrine the philosophy of "Common Sense," and he thought he was coming back from the subtleties of the metaphysicians to the standpoint of the plain man. That he should fall into difficulties and inconsistencies is by no means surprising. As we have seen (section 12), the thought of the plain man is far from clear. He certainly believes that we perceive an external world of things, and the inconsistent way in which Descartes and Locke appeal from ideas to the things themselves does not strike him as unnatural. Why should not a man test his ideas by turning to things and comparing the former with the latter? On the other hand, he knows that to perceive things we must have sense organs and sensations, and he cannot quarrel with the psychologists for saying that we know things only in so far as they are revealed to us through our sensations. How does he reconcile these two positions? He does not reconcile them. He accepts them as they stand.
Reid and various other philosophers have tried to come back to "Common Sense" and to stay there. Now, it is a good position to come back to for the purpose of starting out again. The experience of the plain man, the truths which he recognizes as truths, these are not things to be despised. Many a man whose mind has been, as Berkeley expresses it, "debauched by learning," has gotten away from them to his detriment, and has said very unreasonable things. But "Common Sense" cannot be the ultimate refuge of the philosopher; it can only serve him as material for investigation. The scholar whose thought is as vague and inconsistent as that of the plain man has little profit in the fact that the apparatus of his learning has made it possible for him to be ponderously and unintelligibly vague and inconsistent.
Hence, we may have the utmost sympathy with Reid's protest against the doctrine of representative perception, and we may, nevertheless, complain that he has done little to explain how it is that we directly know external things and yet cannot be said to know things except in so far as we have sensations or ideas.
51. THE CRITICAL PHILOSOPHY.--The German philosopher, Immanuel Kant (1724-1804), was moved, by the skeptical conclusions to which Hume's philosophy seemed to lead, to seek a way of escape, somewhat as Reid was. But he did not take refuge in "Common Sense"; he developed an ingenious doctrine which has had an enormous influence in the philosophical world, and has given rise to a Kantian literature of such proportions that no man can hope to read all of it, even if he devotes his life to it. In Germany and out of it, it has for a hundred years and more simply rained books, pamphlets, and articles on Kant and his philosophy, some of them good, many of them far from clear and far from original. Hundreds of German university students have taken Kant as the subject of the dissertation by which they hoped to win the degree of Doctor of Philosophy;--I was lately offered two hundred and seventy-four such dissertations in one bunch;--and no student is supposed to have even a moderate knowledge of philosophy who has not an acquaintance with that famous work, the "Critique of Pure Reason."
It is to be expected from the outset that, where so many have found so much to say, there should reign abundant differences of opinion. There are differences of opinion touching the interpretation of Kant, and touching the criticisms which may be made upon, and the development which should be given to, his doctrine. It is, of course, impossible to go into all these things here; and I shall do no more than indicate, in untechnical language and in briefest outline, what he offers us in place of the philosophy of Hume.
Kant did not try to refute, as did Reid, the doctrine, urged by Descartes and by his successors, that all those things which the mind directly perceives are to be regarded as complexes of ideas. On the contrary, he accepted it, and he has made the words "phenomenon" and "noumenon" household words in philosophy.
The world which seems to be spread out before us in space and time is, he tells us, a world of things _as they are revealed to our senses and our intelligence_; it is a world of manifestations, of phenomena. What things-in-themselves are like we have no means of knowing; we know only things as they appear to us. We may, to be sure, talk of a something distinct from phenomena, a something not revealed to the senses, but thought of, a _noumenon_; but we should not forget that this is a negative conception; there is nothing in our experience that can give it a filling, for our experience is only of phenomena. The reader will find an unmistakable echo of this doctrine in Herbert Spencer's doctrine of the "Unknowable" and its "manifestations."
Now, Berkeley had called all the things we immediately perceive _ideas_. As we have seen, he distinguished between "ideas of sense" and "ideas of memory and imagination." Hume preferred to give to these two classes different names--he called the first _impressions_ and the second _ideas_.
The associations of the word "impression" are not to be mistaken. Locke had taught that between ideas in the memory and genuine sensations there is the difference that the latter are due to the "brisk acting" of objects without us. Objects impress us, and we have sensations or impressions. To be sure, Hume, after employing the word "impression," goes on to argue that we have no evidence that there are external objects, which cause impressions. But he retains the word "impression," nevertheless, and his use of it perceptibly colors his thought.
In Kant's distinction between phenomena and noumena we have the lineal descendant of the old distinction between the circle of our ideas and the something outside of them that causes them and of which they are supposed to give information. Hume said we have no reason to believe such a thing exists, but are impelled by our nature to believe in it. Kant is not so much concerned to prove the nonexistence of noumena, things-in-themselves, as he is to prove that the very conception is an empty one. His reasonings seem to result in the conclusion that we can make no intelligible statement about things so cut off from our experience as noumena are supposed to be; and one would imagine that he would have felt impelled to go on to the frank declaration that we have no reason to believe in noumena at all, and had better throw away altogether so meaningless and useless a notion. But he was a conservative creature, and he did not go quite so far.
So far there is little choice between Kant and Hume. Certainly the former does not appear to have rehabilitated the external world which had suffered from the assaults of his predecessors. What important difference is there between his doctrine and that of the man whose skeptical tendencies he wished to combat?
The difference is this: Descartes and Locke had accounted for our knowledge of things by maintaining that things act upon us, and make an impression or sensation--that their action, so to speak, begets ideas. This is a very ancient doctrine as well as a very modern one; it is the doctrine that most men find reasonable even before they devote themselves to the study of philosophy. The totality of such impressions received from the external world, they are accustomed to regard as our _experience_ of external things; and they are inclined to think that any knowledge of external things not founded upon experience can hardly deserve the name of knowledge.
Now, Hume, when he cast doubt upon the existence of external things, did not, as I have said above, divest himself of the suggestions of the word "impression." He insists strenuously that all our knowledge is founded upon experience; and he holds that no experience can give us knowledge that is necessary and universal. We know things as they are revealed to us in our experience; but who can guarantee that we may not have new experiences of a quite different kind, and which flatly contradict the notions which we have so far attained of what is possible and impossible, true and untrue.
It is here that Kant takes issue with Hume. A survey of our knowledge makes clear, he thinks, that we are in the possession of a great deal of information that is not of the unsatisfactory kind that, according to Hume, all our knowledge of things must be. There, for example, are all the truths of mathematics. When we enunciate a truth regarding the relations of the lines and angles of a triangle, we are not merely unfolding in the predicate of our proposition what was implicitly contained in the subject. There are propositions that do no more than this; they are _analytical_, _i.e._ they merely analyze the subject. Thus, when we say: Man is a rational animal, we may merely be defining the word "man"--unpacking it, so to speak. But a _synthetic_ judgment is one in which the predicate is not contained in the subject; it adds to one's information. The mathematical truths are of this character. So also is the truth that everything that happens must have a cause.
Do we connect things with one another in this way merely because we have had _experience_ that they are thus connected? Is it because they are _given_ to us connected in this way? That cannot be the case, Kant argues, for what is taken up as mere experienced act cannot be known as universally and necessarily true. We perceive that these things _must_ be so connected. How shall we explain this necessity?
We can only explain it, said Kant, in this way: We must assume that what is given us from without is merely the raw material of sensation, the _matter_ of our experience; and that the ordering of this matter, the arranging it into a world of phenomena, the furnishing of _form_, is the work of the mind. Thus, we must think of space, time, causality, and of all other relations which obtain between the elements of our experience, as due to the nature of the mind. It perceives the world of phenomena that it does, because it _constructs_ that world. Its knowledge of things is stable and dependable because it cannot know any phenomenon which does not conform to its laws. The water poured into a cup must take the shape of the cup; and the raw materials poured into a mind must take the form of an orderly world, spread out in space and time.
Kant thought that with this turn he had placed human knowledge upon a satisfactory basis, and had, at the same time, indicated the limitations of human knowledge. If the world we perceive is a world which we make; if the forms of thought furnished by the mind have no other function than the ordering of the materials furnished by sense; then what can we say of that which may be beyond phenomena? What of _noumena_?
It seems clear that, on Kant's principles, we ought not to be able to say anything whatever of _noumena_. To say that such may exist appears absurd. All conceivable connection between them and existing things as we know them is cut off. We cannot think of a noumenon as a _substance_, for the notions of substance and quality have been declared to be only a scheme for the ordering of phenomena. Nor can we think of one as a cause of the sensations that we unite into a world, for just the same reason. We are shut up logically to the world of phenomena, and that world of phenomena is, after all, the successor of the world of ideas advocated by Berkeley.
This is not the place to discuss at length the value of Kant's contribution to philosophy.[3] There is something terrifying in the prodigious length at which it seems possible for men to discuss it. Kant called his doctrine "Criticism," because it undertook to establish the nature and limits of our knowledge. By some he has been hailed as a great enlightener, and by others he has been accused of being as dogmatic in his assumptions as those whom he disapproved.
But one thing he certainly has accomplished. He has made the words "phenomena" and "noumena" familiar to us all, and he has induced a vast number of men to accept it as established fact that it is not worth while to try to extend our knowledge beyond phenomena. One sees his influence in the writings of men who differ most widely from one another.
[1] "Essay," Book IV, Chapter XI, section 7.
[2] "An Inquiry into the Human Mind," Chapter V, section 5.
[3] The reader will find a criticism of the Critical Philosophy in Chapter XV.
CHAPTER XIII
REALISM AND IDEALISM
52. REALISM.--The plain man is a realist. That is to say, he believes in a world which is not to be identified with his own ideas or those of any other mind. At the same time, as we have seen (section 12), the distinction between the mind and the world is by no means clear to him. It is not difficult, by judicious questioning, to set his feet upon the slippery descent that shoots a man into idealism.
The vague realism of the plain man may be called _Naive_ or _Unreflective Realism_. It has been called by some _Natural Realism_, but the latter term is an unfortunate one. It is, of course, natural for the unreflective man to be unreflective, but, on the other hand, it is also natural for the reflective man to be reflective. Besides, in dubbing any doctrine "natural," we are apt to assume that doctrines contrasted with it may properly be called "unnatural" or "artificial." It is an ancient rhetorical device, to obtain sympathy for a cause in which one may happen to be interested by giving it a taking name; but it is a device frowned upon by logic and by good sense.
One kind of realism is, then, naive realism. It is the position from which we all set out, when we begin to reflect upon the system of things. It is the position to which some try to come back, when their reflections appear to be leading them into strange or unwelcome paths.
We have seen how Thomas Reid (section 50) recoiled from the conclusions to which the reasonings of the philosophers had brought him, and tried to return to the position of the plain man. The attempt was a failure, and was necessarily a failure, for Reid tried to come back to the position of the plain man _and still be a philosopher_. He tried to live in a cloud and, nevertheless, to see clearly--a task not easy to accomplish.
It should be remarked, however, that he tried, at least, to insist that we know the external world _directly_. We may divide realists into two broad classes, those who hold to this view, and those who maintain that we know it only indirectly and through our ideas.
The plain man belongs, of course, to the first class, if it is just to speak of a man who says inconsistent things as being wholly in any one class. Certainly he is willing to assert that the ground upon which he stands and the staff in his hand are perceived by him directly.
But we are compelled to recognize that there are subdivisions in this first class of realists. Reid tried to place himself beside the plain man and failed to do so. Hamilton (section 50) tried also, and he is not to be classed precisely either with the plain man or with Reid. He informs us that the object as it appears to us is a composite something to the building up of which the knowing mind contributes its share, the medium through which the object is perceived its share, and the object in itself its share. He suggests, by way of illustration, that the external object may contribute one third. This seems to make, at least, _something_ external directly known. But, on the other hand, he maintains that the mind knows immediately only what is in immediate contact with the bodily organ--with the eyes, with the hands, etc.; and he believes it knows this immediately because it is actually present in all parts of the body. And, further, in distinguishing as he does between existence "as it is in itself" and existence "as it is revealed to us," and in shutting us up to the latter, he seems to rob us even of the modicum of externality that he has granted us.
I have already mentioned Herbert Spencer (section 50) as a man not without sympathy for the attempt to rehabilitate the external world. He is very severe with the "insanities" of idealism. He is not willing even to take the first step toward it.
He writes:[1] "The postulate with which metaphysical reasoning sets out is that we are primarily conscious only of our sensations--that we certainly know we have these, and that if there be anything beyond these serving as cause for them, it can be known only by inference from them.
"I shall give much surprise to the metaphysical reader if I call in question this postulate; and the surprise will rise into astonishment if I distinctly deny it. Yet I must do this. Limiting the proposition to those epiperipheral feelings produced in us by external objects (for these are alone in question), I see no alternative but to affirm that the thing primarily known is not that a sensation has been experienced, but that there exists an outer object."
According to this, the outer object is not known through an inference; it is known directly. But do not be in haste to class Spencer with the plain man, or with Reid. Listen to a citation once before made (section 22), but worth repeating in this connection: "When we are taught that a piece of matter, regarded by us as existing externally, cannot be really known, but that we can know only certain impressions produced on us, we are yet, by the relativity of thought, compelled to think of these in relation to a cause--the notion of a real existence which generated these impressions becomes nascent. If it be proved that every notion of a real existence which we can frame is inconsistent with itself,--that matter, however conceived by us, cannot be matter as it actually is,--our conception, though transfigured, is not destroyed: there remains the sense of reality, dissociated as far as possible from those special forms under which it was before represented in thought." |
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