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Logic: On Forming the Reasonable Person

“Man He made to serve Him wittily,” said Thomas More in Robert Bolt’s A Man for All Seasons, “in the tangle of his mind.” To serve God wittily requires an orderly mind, one capable of parsing through truths and falsehoods, able to string together arguments. Thus, the trivium endures: grammar, rhetoric, and logic. 

To discuss teaching logic to high school students, we welcome to the podcast Mark Grannis, Heights teacher, attorney, father, and author of The Reasonable Person: Traditional Logic for Modern Life. In this episode, Mr. Grannis discusses what logic is, why it matters today, and how to teach it. Given man’s nature as a rational animal, Mark argues that the study of logic—what he refers to as the art and science of sound reasoning—can improve the daily lives of everyone, regardless of his professional or academic path. Moreover, as social animals, Mark explains how logic can be a powerful means to attaining consensus in the public arena. 

In a world in which thinking has become an increasingly outsourced ability, learning the art and science of thinking well is perhaps more important than ever.


  • 2:45 Introduction
  • 3:30 Law and logic: Mark’s path to the classroom 
  • 5:40 Why (traditional) logic today? 
  • 11:30 Symbolic and traditional logic 
  • 14:30 Examples of traditional logic 
  • 19:00 Practical benefits of logic 
  • 22:55 Logic and writing 
  • 24:40 Teaching logic to high schoolers
  • 26:40 Why write your own textbooks? 
  • 28:40 What’s different about The Reasonable Person?

Recommended Resources 

The Reasonable Person: Traditional Logic for Modern Life by Mark Grannis 

Logic and the Reasonable Person by Mark Grannis

AI and the Take-Home Essay with Matt Mehan

Why a Liberal Arts Education Today? with Michael Moynihan 

About the Guest

Mark Grannis

Philosophy, History

Mark Grannis joined the faculty in 2019 to teach Logic and History, after practicing law for over thirty years and managing the firm he co-founded in 1998. He holds an A.B., cum laude, from Georgetown University, where he majored in Government and Economics. He holds a J.D., cum laude, from the University of Michigan Law School, where he served as an editor of the Michigan Law Review and won several awards for his writing. In 2023, he published The Reasonable Person: Traditional Logic for Modern LifeHe and his wife Sarah have two children, including Will (’21). They live in Chevy Chase with the majestically indifferent Cyrus, King of Purrrrsia.

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