 This was his main objection to pornography: that it was in essence an incentive to sexual acts.  However, as a justification for the radical separation of art and pornography this will not do. For one thing, Clark seems to overlook the fact that there are numerous religious or politically inspired masterpieces that call on people to change their lives or perform certain actions (the Isenheim Altarpiece, 1512–16, or Delacroix’s Liberty Leading the People, 1830, come to mind).