Lucilio Vanini (Taurisano, 1585 – Toulouse, 9 February 1619), who in his works styled himself Giulio Cesare (Julius Caesar) Vanini, was an Italian philosopher, physician and free-thinker, who was one of the first significant representatives of intellectual libertinism. He was among the first modern thinkers who viewed the universe as an entity governed by natural laws (nomological determinism).