Investments are made for profit, and industrial plants and
processes are capitalized on the basis of their profit-yielding
capacity. In the accepted scheme of things among business men,
profits are included as intrinsic to the conduct of business. So
that, in place of the presumption in favor of a simple pecuniary
stability of wealth, such as prevails in the rating of
possessions outside of business traffic, there prevails within
the range of business traffic the presumption that there must in
the natural course of things be a stable and orderly increase of
the property invested. Under no economic system earlier than the
advent of the machine industry does profit on investment seem to
have been accounted a normal or unquestionably legitimate source
of gain. Under the agrarian-manorial regime of the Middle Ages it
was not felt that the wealth of the large owners must, as a
matter of course, increase by virtue of the continued employment
of what they already had in hand - whatever may be the historical
fact as regards the increase of wealth in their hands.
Particularly, it was not the sense of the men of that time that
wealth so employed must increase at any stated, "ordinary" rate
per time unit. Similarly as regards other traffic in those days,
even as regards mercantile ventures. Gain from investment was
felt to be a fortuitous matter, not reducible to a stated rate.
This is reflected, e.g., in the tenacious protests against the
taking or paying of interest and in the ingenious sophistries by
which the payment of interest was defended or explained away.