This chapter surveys the major scientific theories, misconceptions, and philosophical positions surrounding human aging, emphasizing the central role of mitochondrial DNA damage as the most plausible root cause. It reviews historical and contemporary aging hypotheses—from free radicals and telomeres to immune decline and epigenetic clocks—highlighting why none fully explains the aging process. The chapter examines evidence from mutator mouse models, mitochondrial depletion and restoration experiments, and human reproductive biology to show how mitochondrial dysfunction drives energy collapse in aging cells. It also explores emerging rejuvenation strategies such as Yamanaka-factor–based epigenetic reprogramming, the newly identified SB000 reset factor, and mitochondrial transplantation. Broader evolutionary, thermodynamic, and societal perspectives are considered, along with common fallacies in longevity discourse. Together, these lines of evidence argue that human aging is a mechanistically solvable problem and that interventions targeting mitochondrial decline may form the foundation of age-reversal therapies.