“A pencil is an extension of a finger writing in the sand. But our electronic media are extensions of our brains.”

“We read each other through our eyes, and anatomically they are an extension of our brains. When we catch someone's eye, we look into a mind.”

“No power and no treasure can outweigh the extension of our knowledge.”

“Media are really nothing more than extensions of us. It is we, not the media, who are metaphysical. Metaphysics is part and parcel of an organ – the human brain – that processes information both propositionally and presentationally, in words and in images; in reason and in imagination. We believe and refuse to believe. We believe in things that have no physical nature, no material reality, and we refuse to believe in them. We believe in things that not only have a physical, material nature but are also empirically measurable, and we refuse to believe in them. And our media play a role in all of this.”

“Of all man’s instruments, the most wondrous, no doubt, is the book. The other instruments are extensions of his body. The microscope, the telescope, are extensions of his sight; the telephone is the extension of his voice; then we have the plow and the sword, extensions of the arm. But the book is something else altogether: the book is an extension of memory and imagination.”

“…The more enormous our wealth, the more extensive our fears, all our possessions are paled up with new edicts every day, and hung round with gibbets to scare every invader.”