ween 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