For the last decade of his life, my grandfather lived in a world of faceless voices.

His vision lost, he listened to the audiobooks and radio dramas my father brought him: westerns and space operas and stories that, as a child, I would never have spontaneously picked up. But the drive to my grandfather's was long and the tapes already with us, so my father put them on and created for me a childhood filled with the spoken word.

The habit formed, in high school and college I borrowed audiobooks from the library in their large, clunky plastic cases of CDs. At the start of my adult life I had a digital music player in my pocket filled with audiobooks and then-new podcasts.

My flatmate at the time had never met anyone who so constantly listened to 'radio'. Years later she has acclimated (mostly) to the sight of her husband, always around the home with one earbud in, listening to others.

My audio world is largely one of faceless voices. Though unlike my grandfather this is by choice, rather than forced by a failure of biology. What the owners of many of the voices I listen to look like I don't know, and I don't want to know.

The spoken word combines the expansive possibility of writing with the exactingness of visual media. An audiobook narrator can give the text a depth the words alone could never convey. An author reading his work can shift his tone or emphasis to draw attention to particular words far, far more than italics ever could.

The right voice with the right story expands the inner eye to its widest.

But this inner eye is a delicate thing -- a palace of glass seen brightly, if ethereally. Discovering the face of a voice is not an addition, but a subtraction. The face becomes the voice in the way an actor becomes the character they play from a book.

This feeling can be so strong that I suspect the brain treats voices from unknown faces differently than faced voices. That under the scrutiny of an fMRI we could see that while listening to an unfaced voice the visual cortex is still -- allowing the inner eye to see, but a voice with a known face stirs the visual cortex disrupting the imagination.

No longer is there a shifting palace of glass in the mind -- the real vision, too clear, too precise replaces it. An inert, opaque blueprint. The inner eye, forevermore, blind in that direction.