y human being is a closed system, incapable in
the last resort of helping or being helped, of injuring or being
injured, by another. This conception has been finally discredited by
biology, and so far the evangelist must be grateful. The Atonement
presupposes the unity of human life, and its solidarity; it presupposes
a common and universal responsibility. I believe it presupposes also
such a conception of the unity of man and nature as biology proceeds
upon; and in all these respects its physical presuppositions, if we may
so express ourselves, are present to the mind of to-day, thanks to
biology, as they were not even so lately as a hundred years ago.

But this is not all that we have to consider. The mind has been
influenced by the movement of physical and even of biological science,
not only in a way which is favourable, but in ways which are
prejudicial to the acceptance of the Atonement. Every physical science
seems to have a boundless ambition; it wants to reduce everything to
its own level, to explain everything in the terms and by the categories
with which it itself works. The higher has always to fight for its
life against the lower. The physicist would like to reduce chemistry
to physics; the chemist has an ambition to simplify biology into
chemistry; the biologist in turn looks with suspicion on anything in
man which cannot be interpreted biologically. He would like to give,
and is sometimes ready to offer, a biological explanation of
self-consciousness, of freedom, of religion, morality, sin. Now a
biological explanation, when all is done, is a physical explanation,
and a physical explanation of self-consciousness or the moral life is
one in which the very essence of the thing to be explained is either
ignored or explained away. Man's life is certainly rooted in nature,
and therefore a proper subject for biological study; but unless it
somehow transcended nature, and so demanded other than physical
categories for its complete interpretation, there could not be any
study or any science at all. If there were nothing but matter, as M.
Naville has said, there would be no materialism; and if there were
nothing but life, there would be no biology. Now it is in the higher
region of human experience, to which all physical categories are
unequal, that we encounter those realities to which the Atonement is
related, and in relation to which it is real; and we must insist upon
these _higher_ realities, in t