MAXIM: "Quod nullius est id ratione naturali occupanti conceditur." = What belongs to no one, naturally belong to the first occupant.Inst. 2, 1, 12; 1 Bouv. Inst. n. 491.
[Primary Reference.: Henry Maine, Ancient Law, H.S.M., January, 1861, Chapter 8. All definitions referenced from John Bouvier, A Law Dictionary Adapted to the Constitution and Laws of the United States of America and the Several States of the American Union, Childs & Peterson, c1856 - unless otherwise noted.]
In Roman law, "Res Nullius" were physical things which "have not or have never had" an owner. Among these were wild animals, fishes, wild fowl, jewels disinterred for the first time, and lands newly discovered or never before cultivated. Also, among things which "have not an owner" were moveables that were abandoned, lands that were deserted, and the property of an enemy.
ACQUISITION BY OCCUPANCY AND POSSESSION
It was a Roman maxim that the first possessor of a thing becomes the owner by right of occupancy. ("Res nullius fit primi occupantis.") This doctrine was carried forward into English and American Law. Occupancy was defined as an individual taking physical possession of something, which at the moment was the property of no man, (res nullius,) with the view of acquiring property in it for himself. In certain cases, that intention had to be manifested by specific acts constituting "appropriation" to be recognized in law. It was universally believed by the Romans that occupancy was the natural process or "mode of acquisition" by which the commonly-held earth and its fruits became the recognized property of individuals.
The English cultural "world view" continued to recognize the acquisition of property through occupancy and possession as organic "natural law," further recognized in Law as appropriation. Blackstone, in his 2nd book and 1st chapter, summarized:
"The earth, and all things therein were the general property of mankind from the immediate gift of the Creator. Not that the communion of goods seems ever to have been applicable, even in the earliest ages, to aught but the substance of the thing; nor could be extended to the use of it. For, by the law of nature and reason he who first began to use it acquired therein a kind of transient property that lasted so long as he was using it, and no longer; or to speak with greater precision, the right of possession continued for the same time only that the act of possession lasted. Thus the ground was in common, and no part was the permanent property of any man in particular; yet whoever was in the occupation of any determined spot of it, for rest, for shade, or the like, acquired for the time a sort of ownership, from which it would have been unjust and contrary to the law of nature to have driven him by force, but the instant that he quitted the use of occupation of it, another might seize it without injustice"..."when mankind increased in number, it became necessary to entertain conceptions of more permanent dominion, and to appropriate to individuals not the immediate use only, but the very substance of the thing to be used." (Emphasis mine.)
Similar concepts of natural law as respects property were reflected in John Locke's philosophies expressed in "Two Treatises on Government," "An Essay Concerning The True Original, Extent and End of Civil Government," which appeared in 1690. The work is often credited as having a fundamental influence upon the ideology of the Whig party and the beliefs embraced by many of the founders of the United States of America. [Reference.: Two Treatises on Government, "An Essay Concerning The True Original, Extent and End of Civil Government," Irvington Publishers. Inc. c1979.]
Locke proceeded from the assumption of a "state of nature" prior to the formation of political society in which all men were free and equal. He believed that the law of nature, as implanted in the rational nature of each human person, embraced a system of rights. This system prescribed that each should have full and free disposition of himself, subject to no other will. As "owner" of his own person, man had a right to own anything that he removed from the common state of nature by mixing his labor with it as private property - that each man will have "proprietary" (property) rights to the fruits of his labor and to that portion of the earth that he renders fruitful by his labor:
"Though the earth and all inferior creatures be common to all men, yet every man has a property in his own person, this nobody has any right to but himself. The labor of his body and the work of his hands we may say are properly his. Whatsoever, then, he removes out of the state that nature hath provided and left it in, he hath mixed his labor with, and joined to it something that is his own, and thereby makes it his property. It being by him removed from the common state nature placed it in, it hath by this labor something annexed to it that excludes the common right of other men..." (at 27.)
"...As much land as a man tills, plants, improves, cultivates, and can use the product of, so much is his property. He by labor does as it were enclose it from common..." (at 32.)
"...Whatever he tilled and reaped, laid up, and made use of before it spoiled, that was his peculiar right; whatsoever he enclosed and could feed and make use of, the cattle and product were also his..." (at 38.)
"...land that is left wholly to nature, that hath no improvement of pasturage, tillage, or planting, is called, as indeed it is, 'waste,' and we shall find the benefit of it amount to little more than nothing....Tis labor, then, which puts the greatest part of value upon land, without which it would scarcely be worth anything..." (at 42. and 43.)
The concepts of "occupancy" and "possession" exhibited by the mixing of labor or use with an identifiable object, are a continuum of basic Roman concepts of property and ownership. Locke also draws the conclusion that the essential motivation for the formation of societies, (and the purpose of government,) is the protection of the life, health, liberty and property of the individuals who compact to form them, subordinate only to what is legitimately necessary to preserve the whole.
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