"The Practice offers Saturday morning meetings which provide a rhythm of worship, teaching on a particular spiritual discipline and time to experience or "practice" that discipline. This practice time allows participants to get a fuller understanding of how to incorporate the discipline in their daily lives." Spiritual Formation at Willow Creek
This idea of nonduality as "the central essence"  is part of a modern mutual exchange and synthesis of ideas between western spiritual and esoteric traditions and Asian religious revival and reform movements. [note 16] Western predecessors are, among others, New Age ,  Wilber's synthesis of western psychology and Asian spirituality, the idea of a Perennial Philosophy , and Theosophy . Eastern influences are the Hindu reform movements such as Aurobindo's Integral Yoga and Vivekananda's Neo-Vedanta , the Vipassana movement , and Buddhist modernism . A truly syncretistic influence is Osho  and the Rajneesh movement , a hybrid of eastern and western ideas and teachings, and a mainly western group of followers. 
 The topic of self-transcendence is much more nuanced than the polarities that I am presenting in this argument, of course. I have engaged in the discussion of this apparent dichotomy to (a) further explore the dichotomies of my own lived experience between the ecumenical and evangelical perspectives, and (b) further demonstrate how the social Trinity provides an alternative “third way” that brings both extremes into constructive dialogue. For more on self-transcendence, see Conn, Christian Conversion: A Developmental Interpretation of Autonomy and Surrender .