In the biblical creation stories, Adam and Eve lived in perfect unity with God and nature. They did not even know they were different from each other. This is how infants are; they do not discriminate between themselves and their mothers or the environment.
When Adam and Eve ate the fruit of the knowledge of good and evil they suddenly began to discriminate. They knew they were different from each other, and were thus cast out of the garden. This is how it is for people as they mature; they sense a difference between themselves and everything else in the world. From this, grasping and aversion arise.
Now, in this tale, the gods–yes, “gods,” for at this point the biblical God uses the plural “we,” and “us”–even God becomes differentiated with the knowledge of good and evil, this and that, male and female. The gods fear that Adam and Eve may eat from another tree in the garden, the tree of life, and become immortal.
When people first hear about awakening to the vast, unnamable, fathomless void, it is like becoming aware of the second tree in the Garden of Eden. The unnamable void, like the tree of life, is guarded by two cherubs and a flaming sword. The two cherubs, like all dualities, must be transcended. Ceasing conceptualization cuts away the barrier of duality like a flaming sword.
Now, what happens when the fruit from the tree of immortal life is consumed? Again, we are back in the garden living in perfect unity with God and nature–but no longer as unconscious infants, but as consciousness itself. Here is the experience of the eye seeing the eye. Awareness is aware of itself.
This is the meaning of the sages when they say things like “seeing without seeing” and “hearing without hearing” and “speaking without speaking.”