Take Kant, the man Immanuel Kant, who was born and lived at Königsberg,
in the latter part of the eighteenth century and the beginning of the
nineteenth. In the philosophy of this man Kant, a man of heart and
head--that is to say, a man--there is a significant somersault, as
Kierkegaard, another man--and what a man!--would have said, the
somersault from the _Critique of Pure Reason_ to the _Critique of
Practical Reason_. He reconstructs in the latter what he destroyed in
the former, in spite of what those may say who do not see the man
himself. After having examined and pulverized with his analysis the
traditional proofs of the existence of God, of the Aristotelian God, who
is the God corresponding to the _zôon politikon_, the abstract
God, the unmoved prime Mover, he reconstructs God anew; but the God of
the conscience, the Author of the moral order--the Lutheran God, in
short. This transition of Kant exists already in embryo in the Lutheran
notion of faith.

The first God, the rational God, is the projection to the outward
infinite of man as he is by definition--that is to say, of the abstract
man, of the man no-man; the other God, the God of feeling and volition,
is the projection to the inward infinite of man as he is by life, of the
concrete man, the man of flesh and bone.

Kant reconstructed with the heart that which with the head he had
overthrown. And we know, from the testimony of those who knew him and
from his testimony in his letters and private declarations, that the man
Kant, the more or less selfish old bachelor who professed philosophy at
Königsberg at the end of the century of the Encyclopedia and the goddess
of Reason, was a man much preoccupied with the problem--I mean with the
only real vital problem, the problem that strikes at the very root of