d, Descartes was a dogmatist;
but let us rather call him a rationalist. He certainly had no
intention of proceeding uncritically, as we shall see a little later.
If we call him a dogmatist we seem to condemn him in advance, by
applying to him an abusive epithet.

Empiricism, according to Kant, confines human knowledge to experience,
and thus avoids the errors which beset the dogmatist. But then, as
Hume seemed to have shown, empiricism must run out into skepticism. If
all our knowledge has its foundations in experience, how can we expect
to find in our possession any universal or necessary truths? May not a
later experience contradict an earlier? How can we be sure that what
has been will be? Can we _know_ that there is anything fixed and
certain in our world?

Skepticism seemed a forlorn doctrine, and, casting about for a way of
escape from it, Kant hit upon the expedient which I have described. So
long as we maintain that our knowledge has no other source than the
experiences which the world imprints upon us, so to speak, from
without, we are without the power of prediction, for new experiences
may annihilate any generalizations we have founded upon those already
vouchsafed us; but if we assume that the world upon which we gaze, the
world of phenomena, is made what it is by the mind that perceives it,
are we not in a different position?

Suppose, for example, we take the statement that there must be an
adequate cause of all the changes that take place in the world. Can a
mere experience of what has been in the past guarantee that this law
will hold good in the future? But, when we realize that the world of
which we are speaking is nothing more than a world of phenomena, of
experiences, and realize further that this whole world is constructed
by the mind out of the raw materials furnished by the senses, may we
not have a greater confidence in our law? If it is the nature of the
mind to connect the phenomena presented to it with one another as cause
and effect, may we not maintain that no phenomenon can possibly make
its appearance that defies the law in question? How could it appear
except under the conditions laid upon all phenomena? If it is our
nature to think the world as an orderly one, and if we can know no
world save the one we construct ourselves, the orderliness of all the
things we can know seems to be guaranteed to us.

It will be noticed that Kant's doctrine has a negative side. He limits