In their analyses of intergenerational property rights, the founders typically made a distinction between property rights in land and property rights in improvements. Although Creation and the fruits thereof were generally perceived to be, in some fundamental sense the common property of humankind, human-made improvements were thought to be more susceptible of private ownership. Paine employed the land / improvements distinction in Agrarian Justice:
"[I] is impossible to separate the improvement made by cultivation, from the earth itself, upon which that improvement is made . . . but it is nevertheless true, that it is the value of the improvement only, and not the earth itself, that is individual property. Every proprietor therefore of cultivated land, owes to the community a ground-rent . . . for the land which he holds. . . ." f153
and Madison provided much the same analysis in his response to Jefferson's seminal letter:
"If the earth be the gift of nature to the living, their title can extend to the earth in its natural State only. The improvements made by the dead form a charge against the living who take the benefit of them. This charge can no otherwise be satisfyed than by executing the will of the dead accompanying the improvements." f154
A survey of the historical evidence confirms that the founders, by and large, shared the following convictions: 1) that the earth belongs, in some sense, to humankind as a whole; 2) that each generation's liberty to dispose of the land, and other aspects of Creation, is limited by the interests of later generations; and 3) that the legitimate interests of later generations relate to nature in its original state rather than in its improved state. It is nature in its original state that posterity has a claim to, that each generation is obligated to preserve.