the rights of states to be supreme in certain fields of legislation,
but back of this political issue was the economic problem of
slave labor. Illustrations of this kind, which may be indefinitely
multiplied, do not prove that the material, economic changes are the
cause of all other changes, political, scientific, and ethical; for in
many cases the economic changes themselves appear to be the results
of changes of the other kinds. There is a constant action and reaction
between economic forces and other forces and interests in human
society, and the needs of economic adjustment are constantly changing
in nature.

§ 3. #Present-day problems: main subjects#. The particular economic
problems in America at this time are determined by the whole complex
economic and social situation. Two main factors in this may be
distinguished: the objective and the subjective, or the material
environment and the population composing the nation. The one is what
we have, the other is what we are, as a people. These factors are
closely related; for what we are as a people (our tastes, interests,
capacities, achievements) depends largely on what we have, and what we
have (our wealth and incomes) depends largely on what we are. We may
consider the following phases; the first two of the objective factor,
and the last two of the subjective factor.

(a) The basic material resources, consisting of the materials of the
earth's surface and the natural climatic conditions which together
provide the physical conditions necessary for human existence, and
which furnish the stuff out of which men can create new forms of
wealth.

(b) The industrial equipment, consisting of all those artificial