Toward the end of his life, Marshall McLuhan provided a list of the ten things that have changed us the most.

Perhaps the biggest difference between childhood and adulthood is time. The adult frantically looks for more time. The child looks for ways to fill time.

I filled a lot of my childhood time with reading all sorts of stuff: Tolkien’s Lord of the Rings, baseball statistics, Mad Magazine.

And reference books. I loved reference books: atlases of the world,the statistical abstract of the United States, and encyclopedia entries.

After my mom died last year, I had to clean out my childhood home. In the process, I stumbled upon one of my favorite quirky reference books: The Book of Lists.

This 1970s sensation sold nearly ten million copies. It was, well, a book of lists. That’s it.

A lot of the lists were factual, but some of the lists were mere opinions by celebrities or experts in a particular field.

While reminiscing with it, I came across this opinion list by an expert in his field: Marshall McLuhan’s Ten Most Potent Extensions of Man.

Marshall McLuhan was a household name in the 1960s. He was interviewed by numerous outlets, including The Today Show and Playboy. He even made a cameo appearance as himself in a Woody Allen film.

His central theory is that human modes of thinking are altered by media. Media are “extensions” of ourselves, things that add themselves to what we already are. When we start to use a particular extension, it changes us in some way. It changes a person individually; it changes culture as a whole.

Some extensions have minor effects. Some have major effects.

And there are ten, according to that McLuhan list, that have had the most potent effects of all.

Ten Potent Extensions

1. Fire

McLuhan liked to startle, even if it took the form of stating something so obvious like, “Fire is the most potent extension of man.” It’s so obvious, it hardly needs to be said . . except it does.

We forget fire’s importance, just like we don’t often think about the importance of the sun.

Fire gave light. It extended eyesight into the evening and night, expanding our time for activity.

Fire gave warmth. It allowed humans to stay in, or move to, geographic areas that would otherwise be too cold. It, in other words, extended our scope of movement.

Fire cooked food. It extended our stomachs, making it easier to satisfy them, leaving more human energy for other endeavors.

Fire gave strength. It is an extension of muscle. It scared away threatening animals (a weapon). It was used to help create better living spaces (a tool).

2. Clothing

McLuhan dedicated an entire, albeit short, chapter to clothing in his magnum opus, Understanding Media. He pointed out the intuitively obvious: clothes are an extension of our skin.

Our skin, by itself, can withstand only so much cold. A naked person would die of hypothermia on a 70-degree day in the shade. Clothing, by “extending” the skin’s capacity, eliminates such a risk. It also makes the skin tougher, so it can move through harsher terrain.

Characteristically, McLuhan didn’t stop with those obvious observations. He also observed that unclad people eat a lot more than clad, thereby allowing those of us with clothes to conserve how much food we need to forage. Clothing, he said, also increased our sense of privacy and individualism, which eventually developed into style and fashion.

3. The Wheel

Everyone knows the wheel is the most important invention.

But why?

It’s an extension, McLuhan pointed out, of the foot. It allowed the foot to move faster, to move farther, to move more stuff.

But it did a lot more. “The wheel made the road,” McLuhan said. It also allowed us to make pottery, which allowed us to store things. It made the movie camera possible. And, of course, it gave rise to carts, chariots, bikes, and cars.

This entire article could be dedicated to McLuhan’s thoughts about the wheel. Unleashing McLuhan to talk about the wheel is like asking Forrest Gump to talk about Jenny.

4. The Lever

McLuhan liked to quote Archimedes’ boast:

“Give me but one firm spot on which to stand, and I will move the world.”

The lever is the extension of muscle. That’s pretty obvious. It allows the muscle to do more, both in terms of how much it can lift (more power) and how many times it can lift it (saving the muscle’s energy). The lever gave us pulleys, which allowed the development of water wells, which led to communities.

McLuhan also said electronic media is the lever of the modern world: “I will stand on your eyes, your ears, your nerves, and your brain, and the world will move in any tempo or pattern I choose.” He then said private corporations are the Archimedeses applying the lever.

And that was decades before Google, Facebook, and Twitter.

5. Phonetic Alphabet

The phrase “phonetic alphabet” as used by McLuhan refers to our ABCs.

The phonetic alphabet is an extension of language and language is an extension of knowledge.

“Language does for intelligence what the wheel does for the feet and the body. It enables them to move from thing to thing with greater ease and speed and ever less involvement.”

The phonetic alphabet also brought quite a few unfortunate things. Before the advent of writing, McLuhan said, humans lived in an oral world, one where all the senses were fused together and memory was revered. After writing, eyesight conquered the other senses and we became, said McLuhan (borrowing from James Joyce), “ABCED-minded” . . . i.e., “absentminded.”

6. The Sword

To be honest, this one threw me. I couldn’t remember McLuhan writing about the sword. After reviewing my McLuhan books and surfing the web, I don’t think he did.

Which would be characteristic of McLuhan. He often just “threw things out there,” often without a lot of attachment. This would appear to be one of those ideas.

He did, however, say a lot about weaponry in general. The arrow, he said, is an extension of the hand and arm (the rifle, of the eye and teeth). The sword is most obviously like the arrow, an extension of the hand and arm, but also of muscle in general, allowing one to impart more force with more damage than possible without the sword.

I suspect McLuhan was also struck by the social hierarchy that resulted from swords. Swords were expensive. They marked a man’s high social standing.

McLuhan also once reflected on respect given to lesser men if they mastered the art of weaponry, like crippled Vulcan’s sway over the Roman Gods because only he could give them the really good stuff. McLuhan pointed out that western culture, in particular, has always evidenced this ironical obsequious tendency: deference to those with less power if they can give power . . . deference to those of natural inferiority if they can give superiority.

7. Print

This was McLuhan’s favorite whipping boy. He published The Gutenberg Galaxy in 1962 and pretty much laid all of modernity at the feet of the printing press. In the words of biographer Philip Marchand:

“McLuhan argued that the invention of print effected a still more profound transformation [than the phonetic alphabet] in the psyche of Western man, leading to an emphasis on the visualization of knowledge and the subsequent development of rationalism, mechanistic science and industry, capitalism, nationalism, and so on.”

8. Electric Telegraph

The telegraph, yes, but McLuhan includes in this the telephone (the telegraph is the phone’s predecessor). When you look at it like that and today’s ubiquitous cell phone, it’s not hard to agree that the telegraph belongs in the top ten of potent extensions.

Although McLuhan was writing decades before the cell phone, he still thought the telegraph/phone of immense importance. They are enormous extensions of movement, speaking, and listening.

But for McLuhan, there was a lot more to it. “With the telegraph,” McLuhan wrote, “man had initiated that outering or extension of his central nervous system . . .”. The act of putting one’s nerves on the outside of one’s body is unsettling and creates a sense of dread. It’s no coincidence, McLuhan seemed to argue, that the angst-driven philosophy of modern existentialism (specifically, Kierkegaard) started with the rise of the telegraph.

The telegraph, McLuhan also pointed out, started the process of making the world a lot smaller. He popularized the term, “global village.”

9. Electric Light

This one is a bit tricky. McLuhan’s iconic saying was, “The medium is the message,” by which he meant that the important part of a medium is the medium itself. The content of the TV show or book doesn’t matter. The effects of the medium on how we think, live, and behave is what matters. That is the message (that is the most important thing).

When people focus on content, they are blinded to the more important thing: the media itself and its effects.

Switch back to the electric light. It is “pure information,” said McLuhan. Unlike a TV show or newspaper article that carries content whenever it’s in operation, the electric light doesn’t (McLuhan, lover of paradox, said the electric light is a “medium without a message,” which flips his iconic saying on its head . . . but nevermind).

He considered electric light and power as radical twins. They are distinct from their uses. A TV would be pointless unless someone was broadcasting shows; the newspaper would have no existence if it weren’t for its stories. That’s not the case with electric light and power.

10. Radio/TV

Radio and TV bring us to McLuhan’s promised land.

There were other media philosophers before McLuhan. Lewis Mumford, Harold Innis, and Jacques Ellul all wrote about the effects of technology on our minds and culture. And they didn’t like what they saw.

Not McLuhan. He was a cheerleader of the new technology. He wasn’t remotely a Pollyanna, but he definitely liked what he saw in electronics, which put him at odds with the others, especially the elder Mumford (the two men weren’t fans of each other).

Go back and read Philip Marchand’s quote above about McLuhan’s dim view of the printing press and all the modern problems McLuhan associated with it: rationalism, mechanistic industry, capitalism, nationalism.

McLuhan thought electronics reversed all that by extending our central nervous system to burst past the limitations imposed by the oppressive hegemony of sight. Neil Postman (whose Amusing Ourselves to Death is an entertaining gateway into the world of media theory/philosophy) described McLuhan’s historical view this way:

“Electronic communication contains in its structure, that is, its speed, its volume, its multi-directionality, and its forms, the possibility of making us whole again, of retrieving the oral tradition of reclaiming the richness of multiple perspectives . . . Once again, sight, sound, touch, and taste will blend graciously and healthfully.”

I’d suggest that the Internet and the digital revolution of the past 30 years have brought us even closer to McLuhan’s promised land.