Max Planck introduced his constant reluctantly, as a mathematical device to rescueblackbody radiation theory from catastrophic divergence. Classical physics predictedinfinite energy at short wavelengths, while experiments did not. The usual interpretation isthat energy itself is fundamentally quantized. In this paper, the dilemma is re-examinedthrough the SP3 (space-phase) framework. We show that Planck’s constant can beunderstood as a minimum action threshold required for space-phase to sustain coherentexcitation. When combined with observationally derived lower bounds on space-phasestiffness—from coronal mass ejections, photon rings observed by the Event HorizonTelescope, and planetary orbital persistence—a unified stiffness–memory ladder emerges.Quantization is not imposed on nature; it arises because space itself cannot record ortransmit coherence below a minimum stiffness–memory product. The ultravioletcatastrophe thus marks the point where classical equations attempted to assign reality tooscillations that space-phase cannot physically support.