In this two-part series, historian Paul Ham traces how our definition and understanding of the human soul has transformed over thousands of years. Humans have been probing their own invisible inner voice since the Stone Age. But where did the concept of the soul even come from? And is it really what separates the living from the dead?

Historian and writer Paul Ham has traced how our definition and understanding of the human soul has changed over thousands of years.

Human beings have been probing their own inner voice, what it means and how it makes us feel, since the Stone Age.

The human soul has long thought to be an invisible, inner essence that makes each of us distinctively different from the rocks and trees, and which also separates the living from the dead.

But where did it come from? Who invented the concept of the soul? And do we still believe in the soul as inextricably linked to the human spirit?

In this two-part series, Paul investigated first what the pre-modern world called 'the soul'. In this episode, he explores how the concept of the soul disappeared, and became 'the mind' in the modern era.

This episode touches on ancient history, philosophy, neurology, religion, death, epic storytelling, faith, exploration and memory.