Abstract. In this paper we take the three tonal functions tonic, subdominant, dominant out of their usual theoretical domicile – the combinatorics of fifth-related triads enriched by a dialectical interpretation – and redeploy them within an alternative theoretical framework: the combinatorics of the modes of the musical tetractys, enriched by musicaltheoretical interpretations of selected mathematical facts. Section 1 introduces tonal perspectives of the analysis of the fundamental bass. Section 2 provides a short overview of the combinatorics of the three modes of the musical tetractys. The concluding Section 3 binds the two strands of investigation together.