Here, then, is an abundance of types of human association, to be first scrutinized separately, and afterwards considered in relation to each other.
Closely connected with the previous subject is the history of law.
Every type of association, in a way, has its law, whereby its members are constrained to fulfil a certain set of obligations.

Thus our student will pass on straight from the forms of society to the most essential of their functions.

The fact that, amongst the less civilized peoples, the law is uncodified and merely customary, whilst the machinery for enforcing it is, though generally effective enough, yet often highly indefinite and occasional, makes the tracing of the growth of legal institutions from their rudiments no less vitally important, though it makes it none the easier.

The history of authority is a strictly kindred topic.

Legislating and judging on the one hand, and governing on the other, are different aspects of the same general function.