Critical Yeast vs. Critical Mass — Cherie Harder, Lisa Slayton, Louis Kim, Ian DeWaard, and David Bailey
How does cultural and moral renewal actually happen? Two schools of thought emerge to answer this recurring question from the 2026 Understory festival. The first argues that critical mass is the key to social change, requiring enough people mobilized to tip institutions, policies, and norms. The second, based on John Paul Lederach's theory of critical yeast, posits that culture change is rarely the size of a coalition but the quality and placement of small, leavening minorities operating in the right relationships at the right moments.
While the distinction may seem academic, it shapes how funders deploy capital, how organizers build, how pastors imagine their congregations, and how every person of conviction decides where to spend their finite life.
In this debate on tomorrow's theory of change, Cherie Harder, The Trinity Forum president and longtime Comment collaborator, stewards four perspectives. Leadership coach and nonprofit executive Lisa Slayton reflects on the critical yeast change that occurs in Alcoholics Anonymous. Louis Kim, a former VP at Hewlett Packard and now a master of divinity student at Duke, addresses the hazards of critical yeast becoming a "cocoon of righteous irrelevance." Ian DeWaard of the Christian Labor Association of Canada argues that while a small community can model dignity, it cannot on its own secure the kinds of societal changes that underlie that passion and those ideas. And David Bailey, founder of Arrabon, draws us back to the power of two-by-two ministry and what Jesus's form of ministry teaches us about scaling.
Mentioned: The Moral Imagination: The Art and Soul of Building Peace, by John Paul Lederach; To Change the World, by James Davison Hunter; the Twelve Steps of Alcoholics Anonymous and the Rev. Sam Shoemaker; Abraham Kuyper and Pope Leo XIII; "Whispering to a Revolution," by Louis Kim (via Comment); Christianity at the Crossroads: The Global Church from the Print Revolution to the Digital Era, by David N. Hempton; Mark 4; Hebrews 11
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The Understory is a production of Comment (comment.org), published by Cardus (cardus.ca).
Hosted by Anne Snyder. Edited by Allie Crummy. Produced by Tiffany Thompson and Evan Rosa. Subscribe to The Understory wherever you listen, and find every episode at https://comment.org/shows/the-understory/
Episode Highlights
"Movements are rarely built by people obsessed with immediate results, high impact, and fast scale. They are built by people willing to plant faithfully, invest relationally, and surrender outcomes." (Lisa Slayton)
"The stone is in the cathedral. It's not in the quarry." (Louis Kim, on purpose-built change)
"Yeast is necessary, but it's not sufficient." (Ian DeWaard)
"What oftentimes gets lost is the level of formation and discipleship." (David Bailey, on the Civil Rights Movement)
"Show up, be fully present, tell the truth, release the outcomes." (Lisa Slayton, closing reflection)
About the Panel
Cherie Harder (moderator): President of The Trinity Forum, senior fellow at Cardus, and member of Comment's editorial board.
Lisa Slayton: Founding partner and CEO of Tamim Partners, former Pittsburgh Leadership Foundation president, and coauthor of Life in Flux.
Louis Kim: Comment contributing editor and former Hewlett-Packard vice president, now studying hospice and palliative care at Duke Divinity School.
Ian DeWaard: Ontario and Manitoba director of CLAC (Christian Labour Association of Canada), with the union since 2000.
David Bailey: Founder and CEO of Arrabon, a spiritual formation ministry cultivating reconciling communities; public theologian and ordained minister.
Helpful Links and Resources
The Moral Imagination: The Art and Soul of Building Peace, John Paul Lederach's book on peacebuilding and critical yeast: https://global.oup.com/academic/product/the-moral-imagination-9780199747580
"Whispering to a Revolution," Louis Kim's Comment essay on social movements: https://comment.org/whispering-to-a-revolution
Christianity at the Crossroads: The Global Church from the Print Revolution to the Digital Era, David N. Hempton's book on networks, nodes, and nuclei: https://www.cambridge.org/core/books/christianity-at-the-crossroads/85E469C200B4C553A9ADFB1234713E8B
Cherie Harder at The Trinity Forum: https://ttf.org/about-us/trinity-forum-staff
Life in Flux, coauthored by Lisa Pratt Slayton: https://bakerpublishinggroup.com/authors/lisa-pratt-slayton/3814
Louis Kim at Comment: https://comment.org/contributors/louis-kim
Ian DeWaard at CLAC: https://www.clac.ca/Your-voice/Article/clac-director-awarded-the-king-charles-iii-coronation-medal
Arrabon, founded by David Bailey: https://arrabon.com/about
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