ceased to be a central and guiding idea of collective life, a
criterion by which social values are measured? Many people do not
believe in it; many more regard it as so uncertain that they could
not reasonably permit it to affect their lives or opinions. Those
who believe in it are doubtless the majority, but belief has many
degrees; and one can hardly be wrong in saying that, as a general
rule, this belief does not possess the imaginations of those who
hold it, that their emotions react to it feebly, that it is felt to
be remote and unreal, and has comparatively seldom a more direct
influence on conduct than the abstract arguments to be found in
treatises on morals.

Under the control of the idea of Progress the ethical code
recognised in the Western world has been reformed in modern times by
a new principle of far-reaching importance which has emanated from
that idea. When Isocrates formulated the rule of life, "Do unto
others," he probably did not mean to include among "others" slaves
or savages. The Stoics and the Christians extended its application
to the whole of living humanity. But in late years the rule has
received a vastly greater extension by the inclusion of the unborn
generations of the future. This principle of duty to posterity is a
direct corollary of the idea of Progress. In the recent war that
idea, involving the moral obligation of making sacrifices for the
sake of future ages, was constantly appealed to; just as in the
Crusades, the most characteristic wars of our medieval ancestors,
the idea of human destinies then in the ascendant lured thousands to
hardship and death.

The present attempt to trace the genesis and growth of the idea in
broad outline is a purely historical inquiry, and any discussion of