interactions which we ascribe to
certain forces inherent in these elements.

The vegetable and animal natural process begins, at any rate, with the
contact of heterogeneous elements which we characterize as sexual cells
(gametes). They exert upon each other a reciprocal influence which sets
into activity the vegetable and animal process.

The extent to which science is permeated by the hypothesis that
heterogeneous elements reacting upon each other are necessary to a
natural process is best indicated by the atomic theory.

Obviously, it is conceded that the origins of all natural processes
cannot better be explained than by the assumption of the existence in
bodies of invisible particles, each of which has some sort of separate
existence and reacts upon the others.

The entire hypothesis is only the consequence of the concept of a
natural process which the observation of nature has produced in the
human mind.

Even though we conceive the social process as characteristic and
different from the four types of natural processes mentioned above,
still there must be identified in it the two essential factors which
constitute the generic conception of the natural process. And this is,
in fact, what we find. The numberless human groups, which we assume as
the earliest beginnings of human existence, constitute the great variety
of heterogeneous ethnic elements. These have decreased with the decrease
in the number of hordes and tribes. From the foregoing explanation we
are bound to assume as certain that in this field we are concerned with
ethnically different and heterogeneous elements.

The question now remains as to the second constitutive element of a
natural process, namely, the definite interaction of these elements, and
especially as to those interactions which are characterized by
regularity and permanency. Of course, we must avoid analogy with the
reciprocal interaction of heterogeneous elements in the domain of other
natural processes. In strict conformity with the scientific method we
take into consideration merely such interactions as the facts of common
knowledge and actual experience offer us. Thus will we be able, happily,
to formulate a principle of the reciprocal interaction of heterogeneous
ethnic, or, if you will, social elements, the mathematical certainty and
universality of which cannot be denied irrefutably, since it manifests
itself ever and everywhere in the field of history and the living
present.