Martin Eidelberg (US), professor emeritus of art history at Rutgers University, will discuss the reliability and fallibility of provenance and scientific analysis of pictures in determining the authenticity of paintings. Using case histories that he has gathered from his research in preparing a catalogue raisonné of the paintings of Jean Antoine Watteau (1684-1721), he will consider whether such supposedly factual data is reliable, or whether it is subjective and open to the interpretation of scholars.