Eric Staiger (Basic Concepts of Poetics) on the essential unpredictability & uncontrollability of lyric, proceeding as it does from a receptive state, the instantaneous verbalization of a dominating mood or a dream. His theory of genre based not on pigeonholing of formal properties or stylistic analysis, but on clearly differentiated impulses - lyric, epic, dramatic. Mandelstam's notion that future scholars would focus on the "impulse" of the text.

Beneath the worldviews that have become ideologies and normative language practices - the strata of the poetic "impulse".