Form and content in discourse are one, once we understand that verbal discourse is a social phenomenon--social throughout its entire range and in each and every of its factors, from the sound image to the furthest reaches of abstract meaning.
Bakhtin notes the limitations of formalist criticism. Limited to the literary text, isolated from authorial, historical, and social reference, the formalist misses the social interaction of discourses in literature. The formalist or structuralist focuses too much on style (form) and misses the social dynamics going on in the text. Bakhtin argues that the style/form and the content are interrelated and he would prefer that writers and critics look at how style acknowledges its necessary connection to social life, historical influence. This acknowledgement recognizes the dynamic nature of discourse (a social conversation). In such a "social" conversation, there are multiple voices and textual relations. Multiple voices and textual relations imply a varied discourse of many different voices and perspectives (heteroglossia), all of which speak to one another as if in a dialogue.
Bakhtin writes that novelistic discourse exposed the limits of a criticism solely based on style/form. Novelistic discourse is not limited to these flat, abstract rules of style.
The novel orchestrates all its themes, the totality of the world of objects and ideas depicted and expressed in it, by means of the social diversity of speech types (raznorecie) and by the differing individual voices that flourish under such conditions.
Bakhtin wanted to look at the novel, not as a single instrument playing one melody, but as an entire symphony with multiple sounds, harmonious and discordant, all engaging in a dialogue as a whole. Even if we look at the author's individual perspective coming across via all the characters and events in the novel, we have to consider that the author's speech, which is language, is also part of a social dialogue. If we look at the novel in this way, we will see how the author's historical and social context speaks in his/her writing. Just as we can see multiple social perspectives engaging one another in the novel, we can say that these multiple voices inform the author himself. In short, no one "speaks alone." All of these voices are "organized in the novel into a structured stylistic system that expresses the differentiated socio-ideological position of the author amid the heteroglossia of his speech." ("Discourse in the Novel")