Which C.S. Lewis book argues that humans share a universal moral law called the Tao?

The C.S. Lewis book that presents a universal moral law called the Tao is The Abolition of Man. Lewis published the work in 1943 after delivering the Riddell Memorial Lectures at the University of Durham.

In the book, Lewis argues that moral education should recognize objective values rather than treat all judgments as merely personal feelings. He uses “the Tao” as a broad term for the traditional moral principles found across different cultures and religious traditions.

The title refers to Lewis’s warning that technological power without objective moral judgment could reduce humanity’s ability to govern itself. The book is sometimes confused with Mere Christianity, which grew from wartime broadcasts and addresses Christian belief more directly. The Abolition of Man is a compact work of moral and educational philosophy.