If the topic of the first book of Wolff's Jus naturae was clearly ethical and dealt with rights and duties of individual toward herself, other people and God, the second book moves to what could be called economy, by taking its topic property and rights duties pertaining to it.
Wolff begins by noting that the nature of things implies no owner to them. This means, he continues, that originally there was no ownership. In this natural state, all things were in a sense in communal use – not in the sense that there would have been any communities, of course, but in the sense that no individuals owned anything. In this original state, every human being was entitled to just take whatever she found and to use it to satisfy her needs – one could just take an apple and eat it. Because no property existed, no one gathered anything for herself, but things were used only so far as needs for them arose.
Although one might think such an original state was a true paradise, like perhaps Rousseau would have insisted, for Wolff it was just a beginning for further development. In such a state of communal sharing no one would have any incentive to work on things further. Farming and such would not be required for immediate needs – and all such further manipulation of things would be pointless, since anyone would have the right to just take what you had worked on. With no development of industry, sciences could not develop. Since the ultimate duty in Wolffian system was the drive for the perfection, the original state with no property was for him something to be discarded, while private ownership then being almost like a duty.
Original mode of acquiring property is simply seizing something that is ownerless – if a thing does not yet have any owner, Wolff insists, we have a right to take it as our own. After something has an owner, this is not yet possible anymore – if we try to seize upon something that has an owner and we know that it is owned by someone else, we are infringing upon the rights of the owner.
Even if we do not know who the owner is, Wolff says, we should try to find out who she is. Only in the case that the thing has been discarded by its owner or we are incapable of finding who she is are we allowed to make ourselves the owner of the thing. In all other cases we merely possess a thing without owning it. Possession of a thing does give some rights over a thing – for instance, if we do not own a thing, we are not allowed to take it from its possessor – but the right of the owner is greater than the right of the possessor.
All property need not be material, but also rights for doing things could be owned. This is especially pertinent for land owners, because in Wolffian system ownership over land implies several relations of ownership over material and immaterial things. Firstly, ownership of land means ownership over originally ownerless individual things that happen to come upon the land owned, such as ship wreckage. Some things, such as wild animals moving through a land, are not as such owned by the owner of the land, but once the animal has died and stopped its wandering, the rights of the owner of the land come in force. In fact, owner of the land has the right to hunt, fish, pick berries etc. as her immaterial property, and anyone violating that right should forfeit her catch to the owner of the land. Here we see the limited viewpoint of Wolff – in Northern Europe, people have had, since time immemorial, a right to use such goods, even without any clear permission of the owner of the land.
A most striking consequence of Wolff's suggestion of the duty-like nature of property is that this duty never ends. Even if we would be rich, we would still have the duty to take care of our property, and if possible, make our savings bigger. It is somewhat ironic to find a philosopher holding unlimited drive for money a necessary obligation, when this drive could be regarded as a source of many problems of modern society.