The Dual Dialectic of Instrumental Augmentation and Somatic Sovereignty: An Ontological and Engineering Inquiry into Reconfigurable Mobility and Human Agency in the Post-Autonomous Era

Contemporary mobility paradigm shifts—marked by autonomous vehicle architectures, Purpose-Built Vehicles (PBVs), and Software-Defined Vehicles (SDVs)—promise unprecedented liberation from navigational labor. However, this paper argues that the discourse surrounding "freedom of mobility" suffers from a fundamental ontological confusion between two distinct modes of human agency: Instrumental Augmentation (the technological expansion of external possibility space) and Somatic Sovereignty (the unmediated internal cultivation of biological capability). By conducting a multi-disciplinary synthesis spanning vehicle engineering limits, macroeconomic constraints, neurobiology, and existential philosophy, we evaluate the structural realities of modular PBV architectures (e.g., Easy-Swap platforms) alongside the neurochemical mechanics of biological locomotion (running). We demonstrate that while technological augmentation expands the external velocity and volumetric utility of human transport, exclusive reliance on it risks the "paradox of dependency" and the alienation of intrinsic somatic capacity. Conversely, biological movement engages closed-loop proprioceptive feedback and neurochemical flow states (endocannabinoid release), providing an unalienable foundation of human sovereignty. We conclude by outlining a unified paradigm wherein technological mobility serves as a physical enabler without supplanting the essential cultivation of human performance.