This is a brief introduction to a long topic. I will start with a quote. Maybe we should create a quote page?
This comes from D.T. Suzuki (one of the men credited with bringing Zen to the West):
“So with the ‘no-mind,’ it means the unattainability of mind or kokoro, or its nothingness or emptiness (sunyata). And it is all because of this emptiness that one gains the sense of absolute freedom in spite of every restriction and compulsion growing out of one’s sense-experience of individuation. The nothingness of all things means a zero, and their multitudinousness an infinity; and because of this apparent contradiction, the equation become possible, 0 = ∞ and ∞ = 0.”