The human capacity for sustained attention represents a critical cognitive paradox: while essential for numerous high-stakes tasks, perfect vigilance is fundamentally impossible. This commentary explores the theoretical impossibility of maintaining uninterrupted attention, drawing from extensive interdisciplinary research in cognitive science, neuroscience, and psychology. Multiple converging lines of evidence demonstrate that sustained attention is constrained by neural, biological, and cognitive limitations. Neural mechanisms reveal that attention operates through rhythmic oscillations, with inherent fluctuations in frontoparietal networks and default mode network interactions. Neurochemical systems and cellular adaptation effects further underscore the impossibility of continuous, perfect vigilance. Empirical research across domains—including aviation, healthcare, industrial safety, and security—consistently demonstrates rapid declines in attention performance over time, regardless of individual expertise or motivation. Even elite performers like military personnel and experienced meditators exhibit inevitable attention lapses. This paper presents an argument against traditional approaches that seek to overcome these limitations through training or willpower. Instead, it advocates for designing human-technology systems that work harmoniously with cognitive constraints. This requires developing adaptive automation, understanding individual and cultural attention variations, and creating frameworks that strategically balance human capabilities with technological support.