According to Osho, duality in human experience is the mind’s play of opposites—tears and laughter, life and death—arising together from the ego’s dream of a separate 'I.' When one can laugh and weep at oneself, the ego’s lie is exposed; in that clarity, the transient world is seen as a wasteland and only the Divine remains—nondual, real.
We can feel opposite things at once because the small “me” that splits life is pretend; seeing this reveals one real, undivided life.