My Ph.D. is an original interpretation and qualified defence of Hans Jonas’ ethical, metaphysical, and political philosophy. Firstly, I argue that the purpose of his theoretical system is tackling three ills of modernity: nihilism, the ecological crisis, and the threat to human dignity posed by certain biotechnologies. Secondly, I argue that his means of doing so is the rehabilitation of key aspects of Aristotle’s thought. The end result is a framework of norms and political institutions for governance in light of the above concerns.