William Craig

饰：Philosopher

Franchelle Stewart Dorn

饰：Narrator,unknown episodes,

Stephen Toulmin

饰：Philosopher,unknown episodes,

Robert C. Solomon

饰：Philosopher,unknown episodes,

Hans-Georg Gadamer

饰：Philosopher,unknown episodes,

彼得·辛格

Peter Singer

饰：自己

Arne Næss

饰：自己

Jonathan Glover

饰：Self,unknown episodes,

John Searle

饰：Self,unknown episodes,

David Keith Miller

David Keith Miller

饰：Additional narration,unknown episodes,