"... You've got to stand for something, or you'll fall for anything ..."

As was indicated earlier, property was first "possessed" by someone.  That is, it was simply appropriated from nature and kept close at hand where the acquiring individual could exert his physical prowess in order to retain possession and use of it.

There will be some, usually those opposed to private ownership, who will say that such initial appropriation was actually an act of theft.

This however is simply not so.  For something to be stolen, a violation of the boundary of an owner would have had to occur.

If the property in question was not owned, then it follows that the mere act of taking it from nature and possessing it is not and could not be theft, for there was not an owner to be victimized by a usurpation of his ownership over the object.

Even after ideas of ownership had been developed and widely accepted, laying "claim" was still the way that unowned property, and in particular the property of land, came into human possession and ownership.

Some call this system "finders keepers".  For clarity, we will use the term "lay claim".