There are also differences between the cartoon and the fresco. First of all, we see that at the center the figure normally identified as “the Thinker” is missing; many say it has the face of Michelangelo. It was probably added in 1511 when, according to Vasari, Raphael was taken secretly by Bramante to see the Sistine Chapel. Two portraits are also missing: the self-portrait of Raphael and the portrait of Sodoma. It is interesting to note how Raphael portrayed himself among philosophers and not among artists, as if to say that art and painting are manifestations of the mind not inferior to philosophical speculations.