The laws run both ways and the universe runs one way. ΛCDM grounds the thermodynamic arrow in an assumed immaculate beginning, smooth, dense, gravitationally unwound, whose selection Penrose priced at one part in 10^(10^123). Inflation regresses the problem to a still-more-special pre-inflationary state, and fluctuation accounts collapse into Boltzmann-brain pathology. The arrow is an axiom in costume.
A universe-wide singular origin must carry the entire arrow in its initial condition: with time itself starting at t = 0, there is no earlier dynamics to set the direction, so the model's only move is to posit the most improbable state in the history of counting and decline to explain it.
SCT grounds the arrow in dynamics rather than decree. Our patch began as the dense, ordered deposit of a superluminal collision, a localized injection of bulk kinetic energy into a small region of an eternal manifold (P22, P25), not a random draw from a global phase space, so its low entropy is the ordinary signature of a recent energetic event, the way a fresh crater is no miracle of improbability. From that deposit forward, one mechanism runs the clock: gravitational systems shed order irreversibly through three-body ejection and dynamical friction, the mesh dissipation of P14, and its observational equivalence to expansion (P16) makes the cosmological arrow and the thermodynamic arrow two readings of one ongoing process. Time points the way the hierarchy unwinds.
The regress stops because the framework is eternal at the top (P1): no global initial condition exists to be fine-tuned, only an endless cycle in which collisions concentrate order locally and dissipation spends it (P28), each patch inheriting its arrow from its own founding event. Boltzmann brains lose their advantage in the same stroke, since observers arise inside dissipating collision deposits, the generic structured environment, rather than from thermal accidents in equilibrium.
Two working premises set the direction, the same pair that identifies dark energy: the arrow and the acceleration are one dissipation observed at different scales. The foundations are laid out in Paper 1, From Chaos to Convergent Foundations (P14 through P16, with the eternal-cycle context of P27 and P28).
The dissipation arrow is load-bearing physics, not philosophy: it requires the mesh-decay signatures that drive it, secular orbital evolution at the registered rates (lunar-ranging scale locally, the Λ_eff dynamics cosmologically). Demonstration that gravitational systems do not secularly dissipate as P14 requires, or a confirmed dark energy that is exactly constant (no mesh decay to point time with), would sever the arrow from its engine and return it to axiom status, for SCT as well.