Along with Marx, Durkheim, and Weber, W. E. B. Du Bois is often considered one of the founders of sociology. Each of these authors contributed something unique to the discipline. For Marx, it was a historicist outlook and the ability to use the archive as a sociological tool. For Durkheim, it was statistics (as in his foundational text, Suicide, published in 1897, which tracked suicide rates among Protestants and Catholics). For Weber, it was attention to the material force of ideas in society. In direct contrast to Marx, who claimed in The German Ideology that "the ruling ideas of every age are the ideas of the ruling class," Weber argued in The Protestant Ethic and the Spirit of Capitalism that Protestant ideas about salvation had been necessary for producing a class of people who would work and earn for the sake of working and earning.
Du Bois's major contribution to the discipline of sociology was the use of ethnography to bring forward things about black life that couldn't be tracked using more "scientific" tools like statistics and historical archives. His inclusion of music in The Souls of Black Folk is a prime example of this. His point is not just to give a cold, scientific description of black people. This would, paradoxically, reinscribe the notion of black people as objects, even while providing large amounts of data on them. One of Du Bois's goals throughout his corpus is to allow black voices to speak for themselves and to portray black people as subjects. This holds true, for example, in his later text Black Reconstruction, in which he argues explicitly that black agency was key to overturning the institution of slavery and carrying out many reforms that benefited both black and white people during the reconstruction era (such as the introduction of public schools). The inclusion of music in Souls has a similar impact. It disrupts the pattern of treating black people as objects of scientific study—something that has, in American history, often gone together with treating them as objects of economic extraction. Something that exceeds the scientific imagination breaks in, opening up space in an ethnographic account for black subjects to speak for themselves.
This is also why Du Bois pairs each musical phrase with a poem at the beginning of each chapter. The poems are, for the most part, written by respected Europeans, such as Lord Byron, who wrote the lines that Du Bois places at the top of his examination of Booker T. Washington. The chapter on Washington has to do with the notion that black folks could succeed in American society through industrial education and the "little green ballot" of hard work and individual effort, rather than through political struggles for suffrage and other benefits of American citizenship. The major subject of the chapter is the tension between individualism and collective struggle, between "self-help" and the benefits of citizenship in a larger community. Du Bois's point is that, paradoxically, in order to become fully actualized as individuals, black people must participate in a collective struggle for citizenship and for the rights (like voting) that go with citizenship. This is precisely the point that Byron makes: those enslaved must themselves strike the blow for freedom.
Du Bois's point, here, is not, however, simply to "proof-text" his arguments from white sources. He is not just saying "look! A respected white person said something similar to what I'm saying, so you should pay attention!" That might be the function of his inclusion of the poem without the music. But remember that the purpose of the musical phrase here is to allow black life itself to speak. Including the musical phrase alongside a quote from Byron or some other European, then, functions not to validate black life by European intellect, but to allow black life to talk back to a European imagination that might treat it as an object of study. European authors might (explicitly or implicitly) talk about blacks (the "bondsman" in Byron's poem can easily be read as a figure for enslaved people of African descent, as Byron did not write in a vacuum and chattel slavery was a living reality in his time). By including their writing alongside music and other documentation of black life, Du Bois turns the gaze of black people back on Europeans, making the European author an object to be understood from the vantage point of the other side of Euro-American civilization. This is the same point that Du Bois makes in the chapter "The Souls of White Folks" (a kind of sequel to The Souls of Black Folk), which appeared in his book Darkwater. Here he writes, explicitly, of how the white "soul" can only be truly known from his vantage point as a black person:
Of them I am singularly clairvoyant. I see in and through them. I view them from unusual points of vantage. Not as a foreigner do I come, for I am native, not foreign, bone of their thought and flesh of their language. Mine is not the knowledge of the traveler or the colonial composite of dear memories words and wonder. Nor yet is my knowledge that which servants have of their masters, or mass of class, or capitalist of artisan. Rather I see these souls undressed and from the back and side. I see the working of their entrails. I know their thoughts and they know that I know. This knowledge makes them now embarrassed, now furious. They deny my right to live and be and call me misbirth! My word is to them mere bitterness and my soul, pessimism. And yet as they preach and strut and shout and threaten, crouching as they clutch at rags of facts and fancies to hide their nakedness, they go twisting, flying by my tired eyes and I see them ever stripped—ugly, human.
What Du Bois says explicitly in Darkwater, he says implicitly in Souls when he juxtaposes "sorrow songs" with high European poetry. It is the European who becomes the object of knowledge. Byron on freedom cannot be fully understood except from within the context of the internal debates among black people about how best to achieve freedom and advancement in a society founded upon their enslavement. Byron is not a commentator on Du Bois's debate with Booker T. Washington. Rather, Du Bois on Washington is a commentary on Byron. The presence of actual slaves, singing actual "sorrow songs" like the ones to which Du Bois includes the music at the beginning of each chapter, is the only way that one can fully understand the themes about which authors like Byron attempted to write.