spirituality without religion

Reading a book by Sam Harris at the moment called Waking Up: Spirituality Without Religion. It is very provocative, and significantly challenging --- I am considering what in the Ashtanga Yoga practice is religious, and what is spiritual?

Is it necessary and possible --- or even desirable --- to tease out from Ashtanga the 'fondness for the iconography and rituals of another religion'?

Notes:
1. The conventional self as we imagine it does not exist.
2. Positive values such as compassion and patience are teachable and practicable skills.
3. The way we think directly influences our experience.

Iconography and ritual are vital and essential to human existence; also, how important is religion as a multigenerational heuristic and risk-minimization transmitter?