harmony, and to establish the due relation between well-being and right
action. This, the moral argument, is the only possible proof for the
existence of God. Theology is not possible as speculative, but only as
moral theology. The certitude of faith, moreover, is only different from,
not less than, the certainty of knowledge, in so far as it brings with it
not an objective, but a subjective, although universally valid, necessity.
Hence it is better to speak of belief in God as a need of the reason than
as a duty; while a logical error, not a moral one, should be charged
against the atheist. The atheist is blind to the intimate connection which
exists between the highest good and the Ideas of the reason; he does not
see that God, freedom, and immortality are the indispensable conditions of
the realization of this ideal.

Thus faith is based upon duty without being itself duty: ethics is the
_basis of religion_, which consists in our regarding moral laws as
(_instar_, as if they were) divine commands. They are not valid or
obligatory because God has given them (this would be heteronomy), but they
should be regarded as divine because they are necessary laws of reason.
Religion differs from ethics only in its form, not in its content, in that
it adds to the conception of duty the idea of God as a moral lawgiver, and
thus increases the influence of this conception on the will; it is simply
a means for the promotion of morality. Since, however, besides natural
religion or the pure faith of reason (the moral law and the moral
postulates), the historical religions contain statutory determinations or a
doctrinal faith, it becomes the duty of the critical philosopher to inquire
how much of this positive admixture can be justified at the bar of reason.
In this investigation the question of the divine revelation of dogma
and ceremonial laws is neither supra-rationalistically affirmed nor
naturalistically derived, but rationalistically treated as an open
question.

The four essays combined under the title _Religion within the Limits of
Reason Only_ treat of the Radical Evil in Human Nature, the Conflict of the
Good Principle with the Evil for the Mastery over Man, the Victory of the
Good Principle over the Evil and the Founding of a Kingdom of God upon
Earth, and, finally, Service and False Service under the Dominion of the
Good Principle, or Religion and Priestcraft; or more briefly, the fall, the
atonement (the Christ-idea), the