Friedrich Wilhelm Nietzsche was a German philosopher and writer who started his career as a classical philologist and turned to philosophy early in his academic career.

Lucius Annaeus Seneca the Elder, also known as Seneca the Rhetorician, was a Roman writer, born of a wealthy equestrian family of Corduba, Hispania.

French aristocrat and political thinker Alexis Charles Henri de Tocqueville transformed how the world understood democracy through his keen observations of 19th-century America.

Jonathan David Haidt is an American social psychologist and author.