of property and derive property therefrom by deduction. Such theories
usually start either from the idea of occupation or from the idea of
creation through labor. Theories purporting to be based on human
nature are of three forms. Some proceed on a conception of natural
rights, taken to be qualities of human nature reached by reasoning as
to the nature of the abstract man. Others proceed upon the basis of a
social contract expressing or guaranteeing the rights derived by
reason from the nature of man in the abstract. In recent thinking a
third form has arisen which may be called an economic natural law. In
this form of theory, a general foundation for property is derived from
the economic nature of man or from the nature of man as an economic
entity. These are modern theories of natural law on an economic
instead of an ethical basis.

Grotius and Pufendorf may be taken as types of the older natural-law
theories of property. According to Grotius, all things originally were
_res nullius_. But men in society came to a division of things by
agreement. Things not so divided were afterward discovered by
individuals and reduced to possession. Thus things came to be
subjected to individual control. A complete power of disposition was
deduced from this individual control, as something logically implied
therein, and this power of disposition furnished the basis for
acquisition from others whose titles rested directly or indirectly
upon the natural foundation of the original division by agreement or
of subsequent discovery and occupation. Moreover, it could be argued
that the control of an owner, in order to be complete, must include
not only the power to give _inter vivos_ but also the power to provide
for devolution after death as a sort of postponed gift. Thus a
complete system of natural rights of property was made to rest
mediately or immediately upon a postulated original division by
agreement or a subsequent discovery and occupation. This theory should
be considered in the light of the facts of the subject on which
Grotius wrote and of the time when he wrote. He wrote on international
law in the period of expansion and colonization at the beginning of
the seventeenth century. His discussion of the philosophical
foundation of property was meant as a preliminary to consideration of
the title of states to their territorial domain. As things were, the
territories of states had come down in part from the past. The titles
rest