When a person tries to understand subtle things by mathematical calculations alone, he has come into the dense sphere. He does not want to become free, and he wants to make the spirit, which is the finest thing, gross and intelligible. Therefore it is of the greatest importance for spiritual attainment to develop free perception. I have seen people go into a trance or dive into a deep meditation and yet lack free perception. And then it is of no value. They are not really spiritual. A really spiritual person must have a mentality like liquid, not like a rock. A mentality that is moving, not crude and dense.