John S. Tanner, Notes from an Ameteur: A Disciple’s Life in the Academy (Provo, UT: Religious Studies Center; Salt Lake City: Deseret Book, 2011), 25–7.
Words, for me, are like rocks for a geologist. I’m curious about where they come from and how they change over time. Some words are like metamorphic rocks, acquiring new meanings through the years. Others are like conglomerate rocks, comprising linguistic chunks from earlier languages.
One such word is “enthusiasm.” “Enthusiasm” has a fascinating etymology and an equally fascinating intellectual history. It comes from the Greek enthousiasmos, which consists of the root words “theos” (god) and “en” (in). Thus “enthusiasm” literally means “God within.” I like that. To be enthusiastic is to be inspired or, more precisely, possessed by God. In ancient Greece, enthusiasm connoted a sort of divine madness.
This, however, was not necessarily seen as a good thing. It was not a compliment to call someone enthusiastic. Not for ancient Greek philosophers—lovers (“philo”) of wisdom (“sophos”) and natural rivals of those claiming prophetic or poetic inspiration. Nor for Enlightenment philosophes, whose distaste for enthusiasm was shaped by sectarian wars of religion. In the eighteenth century, Dr. Samuel Johnson famously defined “enthusiasm” as “a vain belief of private revelation.”  He went on to quote Locke, who attributed enthusiasm to “the conceits of a warmed or overweening brain.” 
I was surprised when I first discovered that hostility toward enthusiasm had been a staple of Western intellectual history. Enthusiastic by nature and nurture, I assumed that enthusiasm was an unadulterated good. As a product of American and Latter-day Saint culture, my sympathies lay with Emerson, who asserted that “nothing great was ever achieved without enthusiasm.” 
Yet, as I’ve grown older, I’ve come to recognize the perils of enthusiasm untethered to intellect. Hugh Nibley calls this “zeal without knowledge,”  echoing Paul’s criticism of the Jews for having “a zeal of God, but not according to knowledge” (Romans 10:2). I have come to be wary of those who speak with more passion than real understanding and to prize the views of those who have paid the price for genuine knowledge.
Yet the well-known dangers of uninformed enthusiasm, or zeal without knowledge, ought not to lead us to disparage enthusiasm or zeal themselves. I am an advocate of enthusiasm and zeal, but zeal with knowledge and enthusiasm informed by intellect. Knowledgeable zeal, informed enthusiasm—these are indispensable for us as faculty in our roles as teachers and scholars.
Great teaching and scholarship require great learning, but they also require fire in the belly, the kind that inspires us to learn and lights the fire of learning in others. Unlike Mr. McChoakumchild in Dickens’s Hard Times, who sees his job as cramming his charges’ heads full of facts, our task is to instill lifelong enthusiasm for learning. 
Such enthusiasm is best caught rather than taught. Many caught it from Henry Eyring, the renowned Latter-day Saint scientist, whose biography I recently read. Eyring possessed unparalleled knowledge of chemistry, matched by unpretentious, childlike enthusiasm. His boyish, buoyant enthusiasm persisted to the very end of his days. On his deathbed, he excitedly told his son Ted, a fellow chemist, “I’ve thought of a new way to teach calculus that is much easier to understand.” He was also generating new research ideas. Several of his scientific papers were published posthumously, the products of undiminished passion for scholarly inquiry. There is something divine about such enthusiasm, as many of Eyring’s colleagues and students sensed. 
As our students sense our enthusiastic love of learning, they too glimpse God within us. For me, teaching with enthusiasm is an aspect of teaching with the Spirit. I feel the Spirit’s presence in those moments when my classes come alive with learning. At such times, the classroom can feel almost holy. And I sense that I am not simply covering material but uncovering it with my students and, in the process, discovering again the joy that first drew me to my field.
President Marion G. Romney said that he knew when he was teaching by the Spirit: it was when he learned from what he taught.  Likewise, Emily Dickinson said that she couldn’t define great poetry but that she knew it when she read it because it felt like the top of her head was taken off.  This has been my experience when I am teaching and learning with the Spirit.
We are charged to teach every subject with the Spirit. How can we teach with the Spirit if we do not teach with enthusiasm informed by intelligence? Is not such enthusiasm a manifestation of God within us? Ours is the Promethean task of sharing fire from heaven. But unlike Prometheus, we do so with the approbation of a God whose glory is intelligence, or light and truth. He delights when his glory dwells within us.
 Samuel Johnson, The Dictionary of the English Language, in Norton Anthology of English Literature, 7th ed. (New York: W. W. Norton & Company, 2000), 1:2723.
 John Locke, An Essay Concerning Human Understanding (Cleveland, OH: World Publishing Company, 1964), 430.
 Ralph Waldo Emerson, Circles: An Essay (Hoboken, NJ: Bibliobytes, 2011).
 Hugh Nibley, “Zeal Without Knowledge,” in Nibley on the Timely and the Timeless, 2nd ed. (Provo, UT: Religious Studies Center, Brigham Young University, 2004), 281–99.
 Charles Dickens, Hard Times (New York: NAL Penguin, 1961).
 Henry J. Eyring, Mormon Scientist: The Life and Faith of Henry Eyring (Salt Lake City: Deseret Book, 2007).
 Theodore A. Tuttle, “Teaching the Word to the Rising Generation,” address delivered July 10, 1970, at BYU summer school, 8–9.
 Emily Dickinson, in Familiar Quotations, 13th ed. (Boston: Little, Brown & Company, 1955), 649.