Is painting superior?
Leonardo thought so. He wrote that, between painting and sculpture, "painting is the more beautiful and the more imaginative and the more copious, while sculpture is the more durable but it has nothing else."
Leonardo wrote in his Notebooks about painting and sculpture.
Sculpture shows with little labour what in painting appears a miraculous thing to do; to make what is impalpable appear palpable, flat objects appear in relief, distant objects seem close. In fact painting is adorned with infinite possibilities which sculpture cannot command.
Painting can make what is not real, real. A painter can use linear and atmospheric perspective to create a convincing illusion of reality—an illusion which is difficult to achieve.
And how can you sculpt mist or clouds, or the appearance of reflective surfaces?
In the first place sculpture requires a certain light, that is from above, a picture carries everywhere with it its own light and shade. Thus sculpture owes its importance to light and shade, and the sculptor is aided in this by the nature, of the relief which is inherent in it, while the painter whose art expresses the accidental aspects of nature, places his effects in the spots where nature must necessarily produce them. The sculptor cannot diversify his work by the various natural colours of objects; painting is not defective in any particular. The sculptor when he uses perspective cannot make it in any way appear true; that of the painter can appear like a hundred miles beyond the picture itself. Their works have no aerial perspective whatever, they cannot represent transparent bodies, they cannot represent luminous bodies, nor reflected lights, nor lustrous bodies—as mirrors and the like polished surfaces, nor mists, nor dark skies, nor an infinite number of things which need not be told for fear of tedium.Or is Sculpture Superior?
Of course, sculptors and their supporters had their own reasons for believing that sculpture was better than painting as an art form. Sculptors argued, for instance, that their medium had the advantage of representing things in three dimensions, while painting could only represent something fixedly from one angle. Especially in the late Renaissance, Mannerist and Baroque periods, sculptors emphasized the three-dimensionality of their works and the ability to view them from many different angles. Giambologna, a Flemish sculptor active in Italy in the late 1500s, was renowned for making sculpture that the viewer needed to see from every angle in order to comprehend the representation fully (good examples of this include his bronze Mercury sculptures and the marble Rape of the Sabines).
Part of the reason he did this in almost all of his works was surely to celebrate the art of sculpture and (to his eyes) its advantages over painting. Naturally, painters had a response to this criticism: many of them, most famously Titian, sometimes painted mirrors in their compositions—this trick allowed them to represent people or objects seen from more than one angle. Often, doing this was a direct response to the ongoing debate about superiority of painting or sculpture. This debate (like the one about the superiority of the visual arts or poetry) was known in Renaissance Italy as the Paragone ("comparison"). The Paragone and the rivalries it fueled undoubtedly helped to inspire and shape many artistic masterpieces.