1. Causality Softening

The SAE framework understands causality as the suppression imposed by 4DD upon the first three layers of remainder (infinity, inexhaustibility, unpredictability). This suppression is not eternal — causality is softening.

The emergence of 5DD (replication error / life) is itself evidence: if causality were perfectly rigid, remainder would be entirely suppressed, and there would be no replication errors, no variation, no evolution, no life, no consciousness. The existence of subjects proves that causality is no longer perfectly rigid.

By "causality softening," this paper does not mean that causal relations disappear. It means: after perturbation, systems find it increasingly difficult to fully restore their prior state of suppression and closure, so that residuals, deviations, and irreversibilities accumulate more easily.

2. Total Cosmic Lifespan and the 5DD Midpoint

Life appeared on Earth approximately 3.8 billion years ago, when the universe was roughly 10 billion years old. The SAE framework's a priori derivation: the total cosmic lifespan is approximately 20 billion years, with 5DD appearing at the midpoint (10 billion years). The first 10 billion years saw causality tightening; the second 10 billion years see causality softening.

In June 2025, Cornell University physicists Luu, Qiu, and Tye, drawing on DESI and DES dark energy observational data, published a paper estimating the total cosmic lifespan at approximately 33 billion years and predicting that the universe will end in a Big Crunch. Their conclusion qualitatively supports the SAE a priori derivation: the universe has a finite lifespan and will ultimately converge rather than undergo heat death.

The numerical discrepancy (20 billion vs. 33 billion) may stem from their model not incorporating the cumulative effects of causality softening. Their calculations operate within the current physics framework, assuming physical laws remain constant. But if causality itself is softening, that assumption does not hold.

3. Cosmic Contraction

Once causality softens to a sufficient degree, the universe begins to contract. Contraction is not destruction — it is the physical expression of convergence. Because causality softening is nonlinear (positive feedback acceleration), the precise onset of contraction cannot be derived from the current framework.

4. Gravitational Waves and Causal Inelasticity

Gravitational waves are oscillations of spacetime itself — not something propagating through spacetime, but spacetime itself rippling. As gravitational waves pass, space stretches and compresses, time fluctuates.

Gravitational waves demonstrate that spacetime is not rigid; it can be perturbed. Within the SAE framework, this carries a deeper implication: each time a gravitational wave passes, if spacetime does not fully recover elastically — if there exists even an extremely small irreversible deformation — then each gravitational wave leaves behind a residual loosening.

Notably, general relativity itself has predicted a related phenomenon: the Gravitational-wave Memory Effect (Christodoulou 1991, Thorne 1992). Physicists have found that after a strong gravitational wave passes, test masses undergo a permanent displacement residual rather than fully returning to their original positions. This effect is a direct consequence of nonlinear terms in general relativity and is currently awaiting experimental verification by LIGO and LISA.

This paper does not equate the gravitational-wave memory effect with "causal inelasticity." The former is a residual displacement effect within general relativity; the latter is a stronger conjecture: if such residuals can accumulate across events and across scales, they may correspond to long-term loosening of spacetime's suppressive capacity. The two are related but not equivalent.

Countless celestial merger events throughout the universe continuously produce gravitational waves. These waves superpose to form the gravitational-wave background — spacetime continuously, weakly, everywhere rippling. Causality softening is not a singular event; it is the cumulative result of countless merger events.

Moreover, this accumulation is nonlinear and self-reinforcing. As the universe evolves, mergers become more frequent, the gravitational-wave background strengthens, causality softens faster, which in turn promotes further convergence and mergers. Early in cosmic history, mergers were rare and softening was slow; later, mergers accelerate and softening accelerates with them. Models that extrapolate linearly or with simple nonlinearity will inevitably miscalculate — specifically, they will place the contraction onset later than it actually occurs.

5. The Milky Way and Andromeda

The Milky Way and Andromeda galaxies are approximately 2.5 million light-years apart, approaching each other at roughly 110 km/s, with a projected merger in approximately 4 billion years.

In current physics, this is a pure gravitational effect. But within the SAE framework, this may not be purely "natural" gravity. If advanced civilizations exist within the Milky Way and Andromeda — civilizations that developed advanced cognition hundreds of millions of years before humanity — these civilizations may already be guiding galactic motion. Gravity as a physical law is unchanged, but the conditions for gravity can be created. Advanced civilizations need not violate physical laws; they need only adjust the distribution of mass within the scope those laws permit. Where mass is placed, gravity pulls. Guiding gravity, not changing gravity.

Similar cases exist within the Milky Way: two ancient open star clusters (NGC 1605a and NGC 1605b) are currently merging — they formed independently, each with its own history, then approached. No one "invited" the other. Approximately half of all stars exist in binary systems. Approach and merger occur at every scale.

6. Summary of Non-Trivial Predictions

The following predictions are conjectures based on the SAE framework, with remainder, open to falsification:

1. The total cosmic lifespan is approximately 20 billion years, with 5DD at the midpoint (when the universe was roughly 10 billion years old), exhibiting anterior-posterior symmetry.
2. The universe will ultimately contract, and contraction is the physical expression of causality softening. The precise onset time cannot be derived due to the nonlinearity of softening.
3. After gravitational waves pass, spacetime retains irreversible micro-deformations (causal inelasticity), and this effect accumulates at cosmic scales.
4. The accumulation of causality softening is nonlinear (positive feedback). Posterior physical models that do not incorporate this effect systematically overestimate cosmic lifespan.
5. Cosmic contraction is the physical expression of causality softening, not a physical event independent of causality.
6. The approach of the Milky Way and Andromeda may not be purely "natural" gravity, but may include the effect of advanced civilizations guiding mass distribution.

7. Conclusion

The narrowest claim of this paper is not 20 billion years, not the Big Crunch, and not the Milky Way and Andromeda. It is a smaller conjecture: if causality is not absolutely rigid, then cosmic evolution should contain some form of accumulable residual interface through which suppressive capacity loosens over time. This paper tentatively conjectures that this interface is gravitational-wave-related inelastic residuals. All other numerical values and cosmological embeddings are working hypotheses developed around this core.

If future observations demonstrate that spacetime responds to gravitational waves in a perfectly elastic manner, the physical mechanism conjecture of this paper is falsified. But the question itself — whether causality is absolutely rigid — remains worth asking.

Appendix: Tension Between 20-Billion-Year Symmetry and Nonlinear Acceleration

Section 2 proposes a total cosmic lifespan of approximately 20 billion years with 5DD at the midpoint, in anterior-posterior symmetry. Section 4 proposes that the accumulation of causality softening is nonlinear and positively self-reinforcing.

An unresolved tension exists between these two claims: if the second half is subject to positive-feedback acceleration, then the second half should not be equal in length to the first. This paper acknowledges this tension. The 20-billion-year figure is a working hypothesis derived from the 5DD midpoint; nonlinear acceleration is a separate working hypothesis derived from gravitational-wave accumulation. The precise reconciliation cannot be provided here. One possibility: the second half still totals approximately 10 billion years, but its distribution is highly uneven (slow early, extremely fast late). Another possibility: the 20-billion-year figure itself requires revision. This is an explicit remainder of this paper, left for future work.