The human mind, with its obvious limitations, is not capable of grasping the immensity of All That Is. As humans, we are limited by what our particular set of physical senses can perceive. We cannot see certain ranges of light (infrared and ultraviolet). We cannot hear sounds below or above a certain frequency. So how are we going to KNOW all the deep truths about everything?
The only way to grasp the underlying principles of All That Is is to take the spiritual route. Profound contemplation on a spiritual level, not a logical path or through mental acrobatics, is the way to experience this. Then it doesn’t become knowledge. It becomes something you can feel deep within. As if the Universe is inside you and you are a part of All That Is.