In one work, this thinker compared Caligula's view that kings were gods and men were beasts to Grotius' concept of 'right by fact.' In another work, this thinker claimed that humans were originally free, but after establishing private property, the title concept came into being. That work by this thinker also claims that political domination originates in the amour-propre. In addition to Discourse on Inequality, this thinker wrote a book that begins 'man is born free, yet everywhere he is in chains.' For 10 points, name this Swiss-French author of Emile and The Social Contract."
a) Jean-Jacques Rousseau
b) Voltaire
c) John Locke
d) Thomas Hobbes