ut to shelter his family, a savage puts into his work
conscience and affection as well as muscular effort; and when the
mother of the family does this work, the altruistic element in it is
still more conspicuous. As society becomes highly organized the
importance of the moral element in all labor increases till the
further progress, or even the existence, of the social order may be
said to depend on it. In the world of business there is now distrust
and turmoil, and revolutions are feared, because of the unfaithfulness
of a class of men to trusts committed to them.[6]

[6] On the ground of convenience, we may classify labor as
physical or mental, according as the work of muscle or of
brain is especially prominent. Digging a ditch requires more
than an average amount of strength and not even an average
amount of intelligence, and it is, therefore, physical labor
rather than mental; while writing a brief or arguing a case
in court requires much power of thought and only a small
amount of muscular strength, and is typically mental labor.
Managing an estate for an absent owner is more largely a
moral function, since the value of the service depends
chiefly on the fidelity of the man who renders it; but
physical and intellectual labor are also involved. These
three types of personal effort are exerted wherever wealth is
created.

_The Requisites of Production._--If we start with nothing but the
earth in its natural state, inhabited by empty-handed men, and seek to
know what is necessary in order that some wealth may be created, we
find that nothing is absolutely necessary except labor. By working for
a few minutes it is possible to get something that will minister
directly to wants. Yet if men begin operations in a state of such
poverty that they have only their bare hands to apply to the elements
about them, they do not commonly get the usable goods immediately. If
a savage wants fish and makes the rudest net with which to catch them,
he makes what is a _capital good_. This is wanted only for the sake of
the consumers' wealth which it will help to produce. The end in view
has all the while been fish; but the man works first on an instrument
for catching them. He makes the net by mere labor, but he catches the
fish by means of labor and the net. Without such instruments to aid in
production a dense population could not live at all, and a very sparse
one could live on