We are trying in this book to give some impression of the principal
changes and developments of Western thought in what might roughly be
called 'the last generation', though this limit of time has been, as it
must be, treated liberally. From the political point of view the two
most impressive milestones, events which will always mark for the
consciousness of the West the beginning and the end of a period, are no
doubt the war of 1870 and the Great War which has just ended. From 1870
to 1914 would therefore be the most obvious delimitation of our study;
and it is a striking illustration of human paradox, that a great stage
in the growth of unity should be marked by two international tragedies
and crowned by the most terrible of all.

Nearly coincident with the political divisions there are important
landmarks in the history of thought. During the 'sixties, while the
power of Prussia was rising to its culmination in the Franco-Prussian
War, the Darwinian theory of development was gaining command in biology.
To many thinkers there has appeared a clear connexion between that
biological doctrine and the 'imperialism', Teutonic and other, which was
so marked a feature of the time. In any case 'post-Darwinian' might well
describe the scientific thought of the age we have in view.

Industrially the epoch is as clearly defined as it is in politics and
science. For in 1871, the year of the Treaty of Frankfort, an act was
passed after a long working-class agitation, assisted by certain eminent
members of the middle class, legalizing strikes and Trade Unions. And
now at the end of the war, all over the world, society is faced by the
problem of reconciling the full rights, and in some cases the extreme
demands, of 'labour', with democratic government and the prosperity and