At the end of the 18th century William Godwin sketched an account in his Enquiry Concerning Political Justice (1793) of the increasing perfectibility of society, predicting the abolition of political institutions, the institution of marriage and the need for private property. With Condorcet's Esquisse d'un tableau historique des progrès de l'esprit, which it predated only fractionally, it represents a high point of enlightenment optimism. Within a very short space of time it was widely attacked, with one of the most trenchant critics beeing the Rev'd Thomas Malthus, who saw sexual desire and the production of children as imposing severe natural limits on the possibilities for more egalitarian and collectivist forrms of social and political order.
William Godwin, Enquiry Conerning Political Justice (1793) Book VIII - http://oll.libertyfund.org/titles/169. This is a big book but especially read Ch 2, and 6 of Bk 2; and chs 5, 6 and 7 from Bk 8.
Thomas Malthus, Essay on Population 1798 - http://oll.libertyfund.org/titles/311
Read esp chap 1, 4, 5, 10-15 and 18-19.
Class slides here