Which 1943 C.S. Lewis book argues that moral values require an objective foundation?

The Abolition of Man argues that moral values require an objective foundation.

C.S. Lewis published The Abolition of Man in 1943 after delivering the Riddell Memorial Lectures at the University of Durham. The book is a compact work of moral philosophy and education criticism. Lewis argues that moral judgments cannot be reduced merely to personal feelings or social conditioning, and he defends what he calls the Tao: a cross-cultural body of basic moral principles.

The book consists of three chapters, followed by an appendix listing examples of moral principles from different traditions. Lewis warns that attempts to reshape human nature through purely instrumental power could ultimately destroy the qualities that make humanity human. The title does not mean the literal disappearance of the human species. Instead, “abolition” refers to the possible loss of objective value, rational judgment, and properly human agency. It is distinct from Lewis’s apologetic works that focus more directly on Christian belief.