At the turn of the twentieth century, numerous Argentine intellectuals embraced positivist thinking in order to claim the ‘superiority’ of the white race and exclude the indigenous and African-descendant population from the foundational mythologies of the Argentinian nation-state. Darwin’s ideas on evolution – especially the concept of ‘survival of the fittest’ as filtered through the work of Herbert Spencer – coloured the discourses of a myriad of Argentine intellectuals, including artists. The creation of a nationalist music was a foremost concern among Argentine composers, who, influenced by these ideas, believed an Argentinian ‘high’ art should ‘elevate’ folk music through European techniques. In this paper, I concentrate on composer Alberto Williams to see how his career and relevant position in the musical milieu influenced and shaped the construction of an Argentine musical canon. I particularly focus on Williams’s speech, later published as an article, titled ‘La patria y la música’ (‘Fatherland and music’), to examine how his ideas on ‘music evolution’ and ‘race’, influenced by racial scientific ideas taken from European Positivism and Social Darwinism, shaped the discourses and development of a national (or nationalist) music in Argentina at the end of the nineteenth and through the twentieth centuries.