Foucault mentions that art and music are not discursive. How is it so? Foucault had interrogated the 'author' for instance, and largely historicises everything. How could art be autonomous for Foucalt, then?
Foucault is drawing on a tradition most clearly articulated (in my estimation) by American philosopher Susanne Langer's theory of symbolic meaning (Philosophy in a New Key-1942) and philosophy of art (Feeling and Form-1953). Art, unlike science and logic dealing with discursive symbolism, is a "school of life" that "the symbolism furnished by our purely sensory appreciation of forms is a non-discursive symbolism peculiarly well suited to the expression of ideas that defy linguistic "projec- tion."" (PNK,Mentor Book, Sixth Printing, 1964, 75). Aesthetic symbols are "presentational" and rooted in the power of "exhibition." In Feeling and Form she writes, "the emotion in the work is the thought in the work. Just as the content of discourse is the discursive concept, so the content of a work of art is the non-discursive concept of feeling; and it is directly expressed by the form, the appearance before us"(FF, 82). And later in her remarks against "Freud's studies of non-discursive symbolism, and Jung's consequent speculations about "archetypes," [that] were all made in the interest of tracing dream symbols to their sources," she asserts:
Non-discursive form in art has a different office, namely to articulate knowledge that cannot be rendered discursively because it concerns experiences that are not formally amenable to the discursive projection. Such experiences are the rhythms of life, organic, emotional and mental (the rhythm of attention is an interesting link among them all), which are not simply periodic, but endlessly complex, and sensitive to every sort of influence. All together they compose the dynamic pattern of feeling. It is this pattern that only non-discursive symbolic forms can present, and that is the point and purpose of artistic construction. (FF, 240-241)
Non-discursive art forms symbolize the "loose" relations of our feelings and emotions in encountering presentational symbols.
From sculpture, music, dance, poetry, or architecture we are moved by an experience of the "interesting," that speaks a "non-literal language," exemplifying the "laws of the imagination." Discursive symbols are concerned with literal meaning and that is not the purpose or experience we have of art. The "emotional import" of the "exhibitable" and "presentable" can work wonders on us--catharsis, for example, in Aristotle's sense is overly discursive since its focus culminates with "moral" interests. We should not moralize the aesthetic, any more than we may aestheticize morality.