The contribution is a perspective and a research direction, not a result.We argue that the map from string-theory compactification data to cosmological thermalisation outcome is well-defined as a function but not computable as one. Drawing on the undecidability of spectral gaps (Cubitt, Perez-Garcia, and Wolf 2015), the undecidability of quantum thermalisation (Shiraishi and Matsumoto 2021), and the meta-theoretical limits of Faizal, Krauss, Shabir, and Marino (2025), we conjecture that the anthropic patch is the recursively enumerable subset of compactification specifications on which a thermalisation-decision procedure halts with a positive answer. This reframes the string-theory multi-vacuum problem as a computability filter rather than a statistical sample. Three observational directions are outlined where this view differs from a smooth statistical anthropic prior. None constitutes a sharp prediction at present. Five open problems are identified.(v1.1) Added Bennett (2026) as a complementary example of representational limits constraining physical verification (Section 5), and as a potential unification target with algorithmic information theory (Open Problem 6). Clarified distinction between computability-theoretic undecidability (this paper) and covariant capacity bounds (Bennett). Minor formatting corrections(v1.2) Added Cheung, Remmen, Sciotti, and Tarquini (2025) as a sharpened characterisation of the decidable S-matrix sector (Section 2), as a contrast case for the undecidability boundary (Section 5), and as a toy analogy for coupling correlations (Section 6.2). Expanded Open Problem 5 with Coleman-De Luccia specifics. Fixed open-problem count in conclusions.
string theory · landscape · computability · undecidability · anthropic selection · spectral gap · thermalisation · Kolmogorov complexity · CMB spectral distortions