and as, in social states, it
is the collective phenomenon that is more easy of access to the
observer than its parts, therefore we must consider and pursue all
the elements of a given social state together and in common. The
social organisation must be viewed and explored as a whole. There is a
nexus between each leading group of social phenomena and other leading
groups; if there is a change in one of them, that change is
accompanied by a corresponding modification of all the rest. 'Not only
must political institutions and social manners on the one hand, and
manners and ideas on the other, be always mutually connected; but
further, this consolidated whole must be always connected by its
nature with the corresponding state of the integral development of
humanity, considered in all its aspects of intellectual, moral and
physical activity' (_Comte_).

Is there any one element which communicates the decisive impulse to
all the rest,--any predominating agency in the course of social
evolution? The answer is that all the other parts of social existence
are associated with, and drawn along by, the contemporary condition of
intellectual development. The Reason is the superior and preponderant
element which settles the direction in which all the other faculties
shall expand. 'It is only through the more and more marked influence
of the reason over the general conduct of man and of society that the
gradual march of our race has attained that regularity and persevering
continuity which distinguish it so radically from the desultory and
barren expansion of even the highest animal orders, which share, and
with enhanced strength, the appetites, the passions, and even the
primary sentiments of man.' The history of intellectual development,
therefore, is the key to social evolution, and the key to the history
of intellectual development is the Law of the Three States.

Among other central thoughts in Comte's explanation of history are
these:--The displacement of theological by positive conceptions has
been accompanied by a gradual rise of an industrial _regime_ out of
the military _regime;_--the great permanent contribution of
Catholicism was the separation which it set up between the temporal
and the spiritual powers;--the progress of the race consists in the
increasing preponderance of the distinctively human elements over the
animal elements;--the absolute tendency of ordinary social theories
will be replaced by an unfailing adh