Value is often placed on an aesthetic object being ‘genuine’, ‘authentic’ and so on, but nothing is ‘authentic’ per se. If we are asked whether what is before us is authentic, our response could justifiably be: ‘Authentic what?’ It might be an authentic oil painting, an authentic Italian painting, an authentic Renaissance painting, yet not an authentic Leonardo da Vinci painting, not the authentic Mona Lisa. Authenticity is always authenticity under one or another description. The question ‘Is it authentic?’ must be replaced by, or understood as, a question of the form ‘Is it an (or the) authentic so-and-so?’. When the question at hand is thus clarified, the term ‘authentic’ tends to become superfluous. . . . Questions of authenticity—of when, where and by whom a picture was painted—are in some cases settled by a complete and dependable record of the work since it left the artist’s hands. When no such record is available, the primary means of seeking to determine whether a picture was painted during a given period or in a given region or by a given artist is expert visual comparison with works already accepted and works already rejected as of the same period or region or by the same artist. The expert eye is, however, fallible, subject to countless perturbations and constantly in a process of learning—of becoming more perceptive and acute through training and study. Furthermore, the corpus of works taken as standards for comparison may itself be revised over time.