Abstract

Quantum computing has been presented as the next revolutionary paradigm in computation, promising exponential acceleration for selected computational problems and potentially transformative implications for cryptography, simulation, and optimization. However, contemporary achievements in quantum information sci- ence remain narrowly constrained demonstrations rather than evidence for scalable universal quantum computation. This paper argues that large-scale fault-tolerant quantum computing may be fundamentally unattainable due to deep physical, ther- modynamic, and informational constraints. The central thesis of this work is that the true purpose of quantum computation is not arithmetic acceleration, but the controlled domestication of quantum reality itself. Such a task may require degrees of coherence, isolation, synchronization, and informational stabilization that become physically impossible at macroscopic scales. We propose that decoherence is not merely an engineering obstacle but potentially a structural feature of physical reality that resists indefinite computational scalability. This paper develops a philosophical and physical critique of the assumptions underlying universal quantum computing, examines the ontological distinction be- tween mathematical simulation and physical realization, and explores whether na- ture itself imposes a computational horizon beyond which coherent quantum computation cannot exist.