|in theory, a social function is "the contribution made by any phenomenon to a larger system of which the phenomenon is a part." In practice, the social function of a thing is its use or application to the benefit of the greater society, in particular, prioritizing those with the greatest need. Thus, the social function of a property, good, resource or service is realized when it is applied to satisfy a general social need or the unmet need of a segment of society.
The 1988 Brazilian Constitution explicitly recognizes the right to decent housing, and provides that property, whether urban or rural, “shall fulfill its social function” (Article 5, §XXIII). Unoccupied buildings or unproductive land, thus, became more susceptible to expropriation in the social interest. Islamic philosophy, prophetic authority and law recognize ownership, but reserve water, pasture and fire as common entitlement of the people with a social function, restricting their privatization.