Epistemic Point of No Return (k*)
“I call k* the epistemic point of no return. Crossing it does not mean that the system has failed: F(Ktk) ≈ 1 may still hold, tests may still pass, and the artifact may continue to operate. What is lost is the rationality of preserving the existing structure as the basis for future modification.”
— Code Structure Evolution (2026), §3
Why it matters
k* supplies the formal hinge of the CSE argument: the moment at which a chain of individually small ungrounded edits compounds into a structural condition that no amount of further iterative repair can rationally undo. It separates the diachronic problem (drift) from its critical phase (irreversibility).
Notes
The asymmetry that licenses k* is structural. Each modification produced without preserved semantic grounding may introduce structural relations whose justification is not durably encoded—neither in the code, nor in the commit history, nor in any stable record. Reconstructing such justification a posteriori requires inverse inference over a codebase whose surface preserves no record of the reasoning that should have shaped it. The relations to be retrospectively justified do not accumulate additively but combinatorially, since their interactions must also be reconstructed.
Replacement, by contrast, is bounded by the current requirements and the desired functional specification, not by the full history of drift. Beyond k*, that asymmetry tips: rebuilding becomes cheaper than salvaging.