The Project Gutenberg eBook, An Introduction to Philosophy, by George

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 
 
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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 
 
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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 
 
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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 
 
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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. 
 
 
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[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. 
 
 
 
 
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 Chap. XIII – Realism and Idealism 
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