peaking, the existence
of an absolutely necessary God cannot be either proved or disproved.
Hence room is left for faith in any moral proofs that may present
themselves to us, apart from science. With this subject ethics, the
science of practice or of practical reason, will have to deal.

The Critique of Practical Reason

Kant's "Critique of Practical Reason" ("Kritik der praktischen
Vernunft"), published in 1788, is one of the most striking
disquisitions in the whole range of German metaphysical literature.
One of its paragraphs has alone sufficed to render it famous. The
passage concerning the starry heavens and the moral law as the two
transcendently overwhelming phenomena of the universe is, perhaps,
more frequently quoted than any other written by a German author.
This is the treatise which forms the central focus of Kant's
thinking. It stands midway between the "Critique of Pure Reason"
and the "Critique of Judgment." Herein Kant takes up the position
of a vindicator of the truth of Christianity, approaching his proof
of its validity and authority by first establishing positive
affirmations of the immortality of the soul and the existence of
God. It also includes a theory of happiness, and an argument
concerning the _summum bonum_ of life, the special aim being to
demonstrate that man should not simply seek to be happy, but
should, by absolute obedience to the moral law, seek to become
worthy of that happiness which God can bestow.

_I.--Analytic of Practical Reason_

Practical principles are propositions containing a general determination
of the will. They are maxims, or subjective propositions, when
expressing the will of an individual; objective, when they are valid
expressions of the will of rational beings generally.

Practical principles which pre-suppose an object of desire are
empirical, or experimental, and supply no practical laws. Reason, in the
scope of a practical law, influences the will not by the medium of
pleasure or pain. All rational beings necessarily wish for happiness,
but they are not all agreed either as to the means to attain it, or as
to the objects of their enjoyment of it. Thus, subjective practical
principles can only be reckoned as maxims, never as law.

A rational being ought not to conceive that his individual maxims are
calculated to constitute universal laws, and to become the b