 The idea, according to Kovel, has roots in the Code of Hammurabi and was first mentioned in Roman law "where it applied to ambiguities between masters and slaves with respect to property"; it also features in Islamic Sharia law, Aztec law and the Napoleonic Code.Kovel highlights the fact that Marx mentioned the idea when he stated that human beings are no more than the planet's "usufructaries, and, like "boni patres familias", they must hand it down to succeeding generations in an improved condition".Kovel has taken on this reading, asserting that, in an eco-socialist society, "everyone will have ... rights of use and ownership over those means of production necessary to express the creativity of human nature", namely "a place of one's own" to decorate to personal taste, some personal possessions, the body and its attendant sexual and reproductive rights.