Galilean argumentation and the inauthenticity of the Cigoli letter on painting vs. sculpture

► Article argues for inauthenticity of 1612 letter to Cigoli widely attributed to Galileo. ► Reconstructs letter's many arguments why painting is superior to sculpture. ► Argues that letter's manner of arguing deviates from usual Galilean open-mindedness. ► Computer analysis of letter's logical illative terms reveals un-Galilean pattern. ► Letter fails to appreciate dynamics of perspective which Galileo grasped very well.