What is the significance of ascension in spiritual traditions?

According to Osho, ascension - the heaven-bound climb prized by many traditions - is a life-denying fantasy. He rejects going where saints and moralists promise reward, calling such heavens sterile, suffocating, and anti-creative. True spirituality, for him, moves opposite: into the rich, messy aliveness of earthly existence, the so-called hell of artists, rebels, and lovers, where creativity and authenticity replace borrowed ideals and posthumous consolation.