Alan Ryan

Stuart D. Warner

William Godwin

Francisco Suárez

Mortimer J. Adler

David Conway

Peter C. Myers

Paul Carus

James Mill

Michael Silverthorne

Elaine Sternberg

Samuel Gregg

John Locke

John Passmore

Saint Augustine

Confucius

Andrew R. Scoble

Socrates

Luigi Turco

James Beattie

Peter Paul Seaton Jr.

Jeremy Shearmur

Andrea Branchi

Jeremy Bentham

Aeon J. Skoble

Michael Huemer

Virginia Postrel

J.W. Semple

Lewis Amherst Selby-Bigge

Mary Campbell Smith

Carlo Lottieri

John Stuart Mill

Plutarch