But such disputes may not only arise concerning the real existence of property and possession, but also concerning their extent; and these disputes are often susceptible of no decision, or can be decided by no other faculty than the imagination.  A person who lands on the shore of a small island, that is desart and uncultivated, is deemed its possessor from the very first moment, and acquires the property of the whole; because the object is there bounded and circumscribed in the fancy, and at the same time is proportioned to the new possessor.  The same person landing on a desart island, as large as Great Britain, extends his property no farther than his immediate possession; though a numerous colony are esteemed the proprietors of the whole from the instant of their debarkment.

But it often happens, that the title of first possession becomes obscure through time; and that it is impossible to determine many controversies, which may arise concerning it.  In that case long possession or prescription naturally takes place, and gives a person a sufficient property in any thing he enjoys.  The nature of human society admits not of any great accuracy; nor can we always remount to the first origin of things, in order to determine their present condition.  Any considerable space of time sets objects at such a distance, that they seem, in a manner, to lose their reality, and have as little influence on the mind, as if they never had been in being.  A man’s title, that is clear and certain at present, will seem obscure and doubtful fifty years hence, even though the facts, on which it is founded, should be proved with the greatest evidence and certainty.  The same facts have not the same influence after so long an interval of time.  And this may be received as a convincing argument for our preceding doctrine with regard to property and justice.  Possession during a long tract of time conveys a title to any object.  But as it is certain, that, however every thing be produced in time, there is nothing real that is produced by time; it follows, that property being produced by time, is not any thing real in the objects, but is the off-spring of the sentiments, on which alone time is found to have any influence.

[Footnote 18.  Present possession is plainly a relation betwixt a person and an object; but is not sufficient to counter-ballance the relation of first possession, unless the former be long and uninterrupted:  In which case the relation is encreased on the side of the present possession, by the extent of time, and dlminished on that of first possession, by the distance, This change in the relation produces a consequent change in the property.]

We acquire the property of objects by accession, when they are connected in an intimate manner with objects that are already our property, and at the same time are inferior to them.  Thus the fruits of our garden, the offspring of our cattle, and the work of our slaves, are all of them esteemed our property, even before possession.  Where objects are connected together in the imagination, they are apt to be put on the same footing, and are commonly supposed to be endowed with the same qualities.  We readily pass from one to the other, and make no difference in our judgments concerning them; especially if the latter be inferior to the former.