Why the Universe Cannot Have an Outside, a Beginning, or an End: A Structural Impossibility Argument for Multiverse, Big Bang, and Heat Death Cosmology

> Modern cosmology has achieved extraordinary empirical success. Cosmic expansion, cosmological redshift, the cosmic microwave background, primordial nucleosynthesis, dark matter and dark energy phenomena, the thermodynamic arrow of time, and the predictive power of general relativity and the ΛCDM model are not in dispute here. What is in dispute is the ontological extension of these models. This paper argues that three dominant cosmological interpretations involve structural overreach when elevated to the level of existence-as-totality: (1) the multiverse as an external explanatory totality, (2) the Big Bang as the absolute beginning of existence, and (3) the heat death as the final termination of existence. By applying minimal structural admissibility constraints—Non-Externalization, Non-Origination, and Non-Termination—the analysis demonstrates: • an external totality is incoherent, • an absolute beginning of existence-as-totality is inadmissible, and • a final ontological termination of existence is structurally impossible. Physical theories describe the evolution of states within existence. They cannot, without structural contradiction, declare the origin, termination, or external grounding of existence itself. No amount of empirical success can remedy a category error. The distinction between physical modeling and ontological grounding is not optional. It is a condition of coherence. This paper forms part of the Wangius Thought System (WTS), a meta-theoretical framework investigating structural limits of totality-level claims across domains of inquiry. The present study applies the Ω-Law (the Three Structural Prohibitions) to cosmology, examining the structural admissibility of multiverse, absolute-origin Big Bang interpretations, and heat death as ontological termination. Foundational components of the framework are developed in: Wangius, The Self-Grounding of Existence-as-Totality; Wangius, The Axiom of Non-Externalizability; Wangius, The Three Prohibitions (Ω-Law); Wangius, The Structural Instability Theorem. Closely related works include Self-Demonstrating Cosmology and Why Infinite Regress Cannot Begin, which develop the cosmological and logical background for the structural analysis presented.