Antoine Coypel, detail from the ceiling of the Royal Chapel, Versailles, 1716
"Le dessein elegant de l'antique sculpture, Joint aux effets naifs que fournit la nature" - Antoine Coypel
The above quotation was brought to my attention by Susanna Caviglia in her essay "Roccoco Classicisms" that accompanied the 2017 "Classicisms" exhibit at the Smart Museum. ( I discuss that exhibit here )
As the catalog pointed out, "Classical art" deserves scare quotes because it has been far from a singularity. The term itself did not appear until after 1810 - a century after Coypel had died.
But since I use it prescriptively , that is exactly how I would define the profession of Classical art. Like any language, it stands upon a foundation of tradition. But in a way unique to the Greco-Roman-Western European tradition, it attempts to naively engage with nature.
In the visual arts -- that engagement is called life drawing.
In the same catalog, Rebecca Zorach offers a similar formulation: "In Vasari's account of the relationship between Masaccio and Masolino working on the Brancacci Chapel, or the competition of Brunelleschi and Ghiberti over the Florentine Baptistery doors, the classical constitutes itself as a matter of volumetric and ordered
forms freely inspired by Greco-roman sculpture yet naturalistically animated" (note: Vasari wrote that Masaccio "gave a beginning to beautiful attitudes, movements, liveliness, and vivacity, and to a certain relief truly characteristic and natural; which no painter up to his time had ever done")
I admire the detail shown at the top of this post - but unfortunately, Coypel (1661-1722) cannot survive comparison with his incredible contemporary, Giovanni Battista Tiepolo (1696-1970). Online, most of Coypel's work looks like it was done by a Disney cartoonist.