Seeking to philosophically ground this idea of first claim to land, the seventeenth-century English philosopher John Locke wrote an interesting argument that appears in his Second Treatise on Civil Government.

In it, Locke posits that each person owns himself, and in consequence the energy of that person is peculiarly his own.

If a man put a plow into the earth and plowed a field, it thus can be said (argues Locke) that the man mixes his property (his labor) with the land which was in a state of nature (unowned), and by this process makes the land his own.

This theory apparently satisfied many, for the idea still persists today that rightful ownership is based entirely upon labor. 

However, it is a rather incomplete argument for it presumes that if the land (for example) is unplowed and un-developed, then it cannot rightfully be owned.

In truth, a man can plow a field and still not own it because he does not value it enough to establish a claim to it. 

Alternately, a man can lay claim to a piece of land and not plow it, yet it can rightfully become his property.