chetype
than does the savage. Thus, both the law and the cause of progress,
which, from lack of evidence, can be but hypothetically substantiated in
respect of the earlier forms of life on our globe, can be actually
substantiated in respect of the latest forms.[4]

If the advance of Man towards greater heterogeneity is traceable to the
production of many effects by one cause, still more clearly may the
advance of Society towards greater heterogeneity be so explained.
Consider the growth of an industrial organization. When, as must
occasionally happen, some member of a tribe displays unusual aptitude
for making an article of general use--a weapon, for instance--which was
before made by each man for himself, there arises a tendency towards the
differentiation of that member into a maker of such weapon. His
companions--warriors and hunters all of them,--severally feel the
importance of having the best weapons that can be made; and are
therefore certain to offer strong inducements to this skilled individual
to make weapons for them. He, on the other hand, having not only an
unusual faculty, but an unusual liking, for making such weapons (the
talent and the desire for any occupation being commonly associated), is
predisposed to fulfil each commission on the offer of an adequate
reward: especially as his love of distinction is also gratified and his
living facilitated. This first specialization of function, once
commenced, tends ever to become more decided. On the side of the
weapon-maker practice gives increased skill--increased superiority to
his products. On the side of his clients, cessation of practice entails
decreased skill. Thus the influences which determine this division of
labour grow stronger in both ways; and the incipient heterogeneity is,
on the average of cases, likely to become permanent for that generation
if no longer. This process not only differentiates the social mass into
two parts, the one monopolizing, or almost monopolizing, the performance
of a certain function, and the other losing the habit, and in some
measure the power, of performing that function; but it tends to initiate
other differentiations. The advance described implies the introduction
of barter,--the maker of weapons has, on each occasion, to be paid in
such other articles as he agrees to take in exchange. He will not
habitually take in exchange one kind of article, but many kinds. He does
not want mats only, or skins, or fishing-gear, b