Short answers, pulled from the story.
Secular Buddhism is a modern western movement that rejects supernatural, paranormal, and mystical elements of traditional Buddhism, including rebirth, karma across multiple lifetimes, heavens, hells, and the authority of monastic hierarchies. It emphasizes full human flourishing within this life rather than liberation from samsara, drawing on Enlightenment skepticism and humanist values.
Stephen Batchelor is widely regarded as the leading proponent; his books Buddhism Without Beliefs (1998), Confession of a Buddhist Atheist (2010), and After Buddhism (2015) laid out the movement's philosophical foundations. Other key figures include Nanavira Thera, S. N. Goenka, Jack Kornfield, Gil Fronsdal, John Kabat-Zinn, and Bhim Rao Ambedkar.
In Confession of a Buddhist Atheist, published in 2010, Batchelor argued that the historical Buddha, Siddhattha Gautama, did not teach rebirth and karma in the sense later Buddhist traditions insisted. He sought to recover the Buddha's original teachings in their fifth-century BCE Gangetic plains context while demonstrating their relevance to contemporary life.
Bhim Rao Ambedkar (1891-1956) established Navayana Buddhism in 1956, a highly secularized teaching derived from the Pali Canon that focused on ethical and social implications and removed metaphysical claims underpinning the caste system he opposed. Though the distinct movement of Secular Buddhism is dated to the late 20th century, some scholars retrospectively recognize Ambedkar's work as a significant precursor.
John Kabat-Zinn developed the Mindfulness-based stress reduction program, an eight-week course, after a 1979 retreat where he asked how to bring the heart of Buddha-dharma into the world without locking it into a culturally bound framework. His 1990 book Full Catastrophe Living drew wider attention to the program, and Zindel Segal, John Teasdale, and Mark Williams subsequently built Mindfulness-based cognitive therapy on that foundation.
Buddhist modernism originated in Sri Lanka in the 19th century as a response to western colonial missionary activism, reshaping Buddhism along Protestant lines to make meditation and texts available to lay practitioners. It spread to Japan, Burma, Thailand, and other Asian countries, but carried internal contradictions: it combined the discourses of modernity with ancestral Buddhism's enchanted canons, belief in rebirth, and deference to monastic power structures that Secular Buddhism later set out to dismantle.