since the Master presented the Gospel which he lived and
died for. The problem of Christianity is thus a twofold problem. On the
one hand, we have constantly to go back to the Fountain-head, because it
is here that the stream is purest. But we have, on the other hand, to
enter into the religious current which surrounds us; and this may be not
so [p.183] pure as it was at its source. Alien waters have entered into
the current--waters of very different taste from those which even the
Founder expected. These have doubtless polluted the stream. But, on the
other hand, good elements--primary and secondary--have entered into the
deepest nature of Christianity itself. These have to be taken into
account. They have been necessitated by the new and ever more complex
situations and conditions into which Christianity has had to enter from
generation to generation. It was comparatively easy for Christianity in
its early beginnings to include within its compass the whole of life.
But by to-day life has branched off in so many new directions;
perplexing problems of knowledge and life have made their appearance. We
dare not dismiss these to a region outside the sphere of influence of
Christianity. Christianity, if it is to remain and increase as a living
force, has to interpret these problems; it has to help us to distinguish
between the chaff and the wheat.

What, then, is the true meaning of Christianity? Eucken shows that it is
not possible to determine the nature of Christianity without realising
that the nucleus common to all religions lies in the fact "that they
manifest and represent a Divine Life, and that such a Life in its inmost
foundation is superior to its external configuration and activity, and
is able to withstand all the changes of time, and to [p.184] maintain
within itself, in spite of all its curtailment through the human
situation, _an eternal truth_." This nucleus lies deeper in Christianity
than in any other religion. But even Christianity itself is not a pure
spiritual nucleus. Much, as we have already noticed, has gathered around
it--much that reveals a lower grade of spirituality. All this
constitutes the clothing of Christianity. The clothing has been changed
again and again in the past. What reason is there for affirming that it
cannot be changed again? It is therefore necessary to differentiate
between the _Substance_ of Christianity and its _Existential-form_. The
Substance constitutes the fundamental Life