Function is a fundamental principle of functional theory, not just mapping the musical sense of the unique being that cannot be penetrated from the outside. Terminological discrepancies manifest as either the same term with different meanings or different terms with the same meaning. The issue is not the discrepancy, which is inevitable, but the claim for a more rigorous scholarly approach or stricter taxonomy to resolve the inability to find suitably precise terminology. This essay traces inconsistencies in the work of advocates of functional theory, such as Parashkev Hadjiev, Evgenii Avramov, Hugo Riemann, Herman Erpf and Sigfrid Karg-Elert, by comparing systems with degrees to those with degrees and functions. In practice, scale degrees and their harmonic identities are also functional. I argue that function in musical experience is not an abstract concept but the perception of a particular chord. The mind may determine the existence of a phenomenon in what has already been heard, but it does not have to manipulate it according to related artificial rational schemes. Harmony teaching should therefore take the simplest route and shorten the journey to perception. For example, the dominant first degree (DI) may more appropriately be described as the cadential six-four chord. In this way confusion of the principal harmonies T and D (the first and fifth degree) can be avoided. While questions about proper student guidance and avoiding confusion are considered, they still remain open.