DIFFICULT TO FATHOM

The reason we have difficulty grasping what exactly the Brahman is, is because of the time, space, and causation nature of our world, its relativity.  Due to this relativity, we can only understand things in relation to other things.

The Brahman, however, is everything.  How can everything be in relation to anything else?  It is anything else.

At the same time, the Brahman cannot be one thing, as our giving it a name suggests, making it even more illusive to our minds.  This is why it is said that the Brahman is something that is experienced, as opposed to something that is known intellectually.