This book investigates the fundamental paradox of how human beings can exist as biological entities within the natural world while simultaneously possessing free will and moral agency. Mary Midgley, a prominent moral philosopher, draws upon evolutionary biology and philosophical inquiry to challenge reductionist views of human behavior. She argues that our evolutionary history does not negate our capacity for freedom but rather provides the necessary framework for the emergence of morality and conscious choice.

Experts recognize this work as a significant contribution to the dialogue between science and philosophy, often citing Midgley's ability to bridge complex academic disciplines. Readers frequently note the clarity of her prose despite the dense philosophical subject matter.