"the self" (Hugo)

From Richard Hugo's The Triggering Town:

The self as given is inadequate and will not do. I remember I was distrustful of both Eliot and Roethke when late in their careers they announced they were happy. But they were being honest. Every poem a poet writes is a slight advance of self and a slight modification of the mask, the one you want to be. Poem after poem the self grows more worthy of the mask, the mask comes closer to fitting the face. After enough poems, you are nearly the one you want to be, and the one you want to be closely resembles you. The happiness Eliot and Roethke spoke of is one that cannot be observed by others because it is only a different way one has come to feel about oneself. "Nearly" and "closely," not "exactly" and "perfectly."

A brief correspondence with poet Dave Smith and the rereading of his essay, St. Cyril's Dragon: The Threat of Poetry, are convincing me that the self evolves but perhaps around some core.