gles 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 bet