The spiritual can only be defined by its transcendence of definition. Not only can it not be grasped with any of the five senses we use to grasp a physical object, but that it is essentially ungraspable.

True, each spiritual entity has its particular sphere which distinguishes it from another. Love is not fear, fear is not love, and neither of them is wisdom. The life-energy of a plant is not the life-energy of an animal and neither one can be the soul of a human being.

Nevertheless, in each spiritual entity is felt something of the other and of the source of all of them—something that is utterly simple and indefinable. That is why a spiritual entity remains elusive to the mind that wishes to resolve and define each thing.

The concrete methods we come to rely upon for life on earth are therefore a hindrance when applied to matters of the spirit. To have any grasp of the spiritual, you need to let go of the urge to resolve and define in tight, isolated packages. You must learn to see things in terms of relationships, directions of movement, dynamic flux. You need a mind where opposites can co-exist without destroying one another.

Which is, essentially, the mind of the human being.