sensibility: we can feel only according to time and space, by lodging what
we feel in space and time; these are the conditions of sensibility.
Phenomena are thus perceived by us under the laws of space and of time.
What do they become in us? They are seized by the understanding, which also
has its forms, its powers of classification, of arrangement, and of
connection. Its forms or powers, or, putting it more exactly, its active
forms are, for example, the conception of quantity being always equal:
through all phenomena the quantity of substance remains always the same;
the conception of causality: everything has a cause and every cause has an
effect and it is ever thus. Those are the conditions of our understanding,
those without which we do not understand and the forms which within us we
impose on all things in order to understand them.

It is thus that we know the world; which is tantamount to stating that the
world exists, so far as we are concerned, only so long as we think
so. Reason would go further: it would seize the most general, the
universal, beyond experience, beyond the limited and restricted
systematizations established by the understanding; to know, for instance,
the first cause of all causes, the last and collective end, so to speak, of
all purposes; to know "why is there something?" and "in view of what end is
there something?" in fact, to answer all the questions of infinity and
eternity. Be sure that it cannot. How could it? It only operates, can only
operate, on the data of experience and the systematizations of the
understanding, which classify experience but do not go beyond it. Only
operating upon that, having nothing except that as matter, how could it
itself go beyond experience? It cannot. It is only (a highly important
fact, and one which must on no account be forgotten)--it is only a sign,
merely a witness. It is the sign that the human spirit has need of the
absolute; it is itself that need; without that it would not exist; it is
the witness of our invincible insistence on knowing and of our tendency to