Sefer Etz Chaim and Tanya

Both texts accept that klipat-nogah contains transformable elements (birur) within the animal soul (nefesh behamit). Text 1 emphasizes the structural duality of the four elements—half good (klipat-nogah's positive aspect) and half evil—with detailed discussion of the liver, blood, and physical remediation through proper nourishment. Text 2 emphasizes the transformative mechanism itself: how divine intellect in the soul converts the 'waters' (desires) of the animal soul into pure good by removing 'soiled garments' (worldly pleasures). Text 1 focuses on the ontological composition and separation; Text 2 focuses on the experiential/contemplative process of elevation. The disagreement is subtle—not contradictory but prioritizing different aspects of how birur and klipat-nogah function.