Naturalia non sunt turpia  

"Nor have we less respect for Palmerin of England who after a risqué scene declares, 'Herein is no offence offered to the wise by wanton speeches, or encouragement to the loose by lascivious matter.' But these are not oriental ideas and we must e'en take the Eastern as we find him. He still holds 'Naturalia non sunt turpia,' together with 'Mundis omnia munda'; and, as Bacon assures us the mixture of a lie doth add to pleasure, so the Arab enjoys the startling and lively contrast of extreme virtue and horrible vice placed in juxtaposition."--"Terminal Essay"