INTRODUCTION 
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pamphlets and news items, commonly of a propagandist 
character. To sift out the significant facts from this mass 
of ex parte evidence, to distinguish the typical from the ex 
ceptional, and to arrange the whole in just order and pro 
portion, is a task which the combined labor of many scho 
lars has not sufficed to accomplish. Least of all has the 
obscurity been cleared away from that elusive mass of be 
liefs, sentiments, ideals and aspirations touching economic 
relationships which go to make up the social philosophy 
of unionism and which account for much of its significance 
to unionists themselves and to society at large. 
Yet it is not enough to obtain a dispassionate view or 
even to ascertain the objective facts. Fruitful understand 
ing of any social movement depends not alone upon know 
ledge of the features peculiar to it, but upon the ability to 
relate those features to social phenomena of a more general 
character, to disentangle the relevant circumstances out of 
which the particular movement arose, to set forth the effi 
cient causes which shaped its growth and to show what it is 
becoming under the influence of forces which are currently 
at work within it or which impinge upon it. For group 
action is conditioned by group thought and group thought 
depends in turn upon group experience, so that any useful 
study of a social movement, more particularly of a class 
movement, necessarily becomes a genetic inquiry into group 
psychology. Such an inquiry, however, is at once confront 
ed by all those obstacles which derive from the present rudi 
mentary state of social science. The student of unionism, 
of political parties or of business enterprise, must make 
use of many generalizations which have yet to be estab 
lished—among them the origin and functioning of social 
classes, the rôle of class conflict in the life of communities 
and the relative weight of heredity and choice, of tradition 
and personal experience, and of economics and general so 
cial environment in determining institutional growth and 
decay. Where so little can be taken as securely given, the