Simmias’ famous epiphenomenalist analogy of the soul-body relation to the harmony and strings of a lyre (together with Cebes’ subsequent objection) leads to Socrates’ initial refutation and subsequent prolonged defense of soul’s immortality in the Phaedo. It also yields in late antiquity significant treatments of the harmony relation by Plotinus (Ennead III 6  4, 30-52) and Porphyry (Sentences 18, 8-18) that present a larger context for viewing the nature of harmony in the soul and the psycho-somatic compound. But perhaps the most detailed treatment of the musical analogy, and certainly the most radical, is to be found in Gregory of Nyssa’s De Hominis Opificio. Gregory’s remarkable development of the musical instrument analogy provides a multi-layered analysis of interrelated causality on the mechanistic, physiological, psycho-somatic and intellectual/spiritual planes. Gregory not only sees mind/soul and body as radically equal and yet multilayered in their mutual development; he also refuses to restrict mind to the brain alone, for all physiological systems, in his view, are holistically and individually expressive of mind’s activity. Gregory’s theory is more innovative than Augustine’s view of the mind/soul-body relation and, in my view, the most important account between Plotinus and Aquinas.