From Dorion Weickmann: Choreography and narrative: the ballet d’action of the eighteenth century in Kant 2007: Cambridge Companion to Ballet:
“The ballet d’action, a narrative ballet, was an invention of the eighteenth century. It replaced the pompous grands ballets of baroque absolutism that had evolved out of the Italian Renaissance intermedii or divertissements, had primarily represented and glorified the sovereign; the ballet d’action, on the other hand, was supposed to tell stories that followed their own narrative logic and lay beyond princely power fantasies.
The emergence of the ballet d’action relied on three factors: first, enlightenment ideas had spread to dance theory. Hence it became possible to introduce the notion that dance could and should be independent from the other arts. Secondly, the academic ballet of the eighteenth century strove towards a technical refinement that aristocratic amateurs practising dance could no longer fulfil. Thirdly, theatre as a cultural institution underwent a process of professionalisation in which the performer and the observer began to be separated from each other.” (p.53)
“They [French ballet theorists of the eighteenth century] intended to supply the dance with an unmistakable and autonomous poetics instead of understanding it as a hybrid form of poetry, music and painting. Against the absolutist demand of servitude the French writers defined form, function and content of ballet in a new way and harmonised all these new components. Instead of presenting mere virtuosity and conceptual emptiness, dance was supposed to translate human emotions and affects. Instead of simply confirming power relationships, dance was now to show ‘la belle nature’ itself, that is, the beauty of the human condition, of human temperaments and chacteristics. Dance literature from the mid-eighteenth century onwards followed this motif of a new sensibility.” (p.55)
“In his [Cahusac] opinion, the poverty of action of the court ballets and divertissements destroyed the aesthetics as well as the function of theatrical dance: ‘L’Opinion commune est que la Danse doit se réduire à un developpment des belles proportions du corps, à une grande précision dans l’exécution des airs, à beaucoup de grace dans le déployment des bras, à une légerté extrême dans la formation des pas.’ [quoted from: Louis de Cahusac: La Danse ancienne et moderne ou Traité historique de la Danse, Paris 1754] (Common opinion assumes that dance can be reduced to the development of beautiful physical proportions, great precision in execution of airs, graceful deployment of the arms and an extreme lightness in making steps.) Yet that was not enough in itself because it would often only mean mechanical repetition.
[…] Cahusac not only demanded that absolute spectacle be replaced by narrative composition but also suggested a dramaturgical structure for all ballets: they were to follow an Aristotelian three-part organisation in which the expostition of the dramatic conflict was followed by its development and its dissolution. Cahusac hoped that clarification of the subject in turn would lead to a revival of ballet.” (p.56)