According to Osho, Chaitanya's achintya bhedabhedavad declares that reality is both one and different: the world and God (matter and spirit) are distinct like a wave yet inseparable from the ocean. Crucially, 'achintya' (unthinkable) means this unity-in-difference cannot be grasped by logic; it must be realized in no-mind, as living experience, where concepts fall away.
Things are both separate and one, like a wave and the ocean, and you truly know this by experiencing it beyond thinking.