Green Wizardry is a handbook of appropriate technology. John Michael Greer details an array of ways in which ordinary people may move away from fragile reliance on the global supply chain towards being able to grow their own food, save amazing amounts of energy, all while integrating with the ecosystem rather than working against it. These notes will go over the foreword and principles as Greer’s explanation of energy, matter, and information is one of the best out there.

In the world of the twenty-first century, appropriate-tech mavens argued, the cheap abundant energy and resources that supported the extravagant machinery of twentieth-century industrial nations would inevitably run short. Before that happened, a new breed of technology had to be invented and put into production. The new technologies they hoped to pioneer would use energy and resources sparingly; they would work with the cycles of nature rather than against them; they would meet human needs without placing unsustainable burdens on the biosphere.

In dozens of different ways, varying with local conditions and resources, people in the appropriate tech movement proved that it was possible to live sustainably, and even comfortably, on a small fraction of the energy and resources most middle-class people in the industrial world thought they needed to sustain their lives.

I’ve come to think that something like the wizards of the early Middle Ages, focused on a somewhat different body of skills, may be one of the best options we have available today. Certain branches of practical knowledge, thoroughly learned and thoroughly practiced by a relatively modest number of people, could be deployed in a hurry to help mitigate the impact of the energy shortages, economic dislocations, and systems breakdowns that await us in the years ahead.

Rather than high-tech solutions, “effort focused on simple technologies that could be put to work by ordinary people–people without six-figure incomes, doing the work themselves, and using readily available tools and resources.”


Energy is the capacity to do work. It cannot be created or destroyed, but the amount and kind of work it can do can change. The more concentrated it is, compared to its surroundings, the more work it can do; the less the difference in its concentration and the background level of energy around it, the less work it can do. Left to itself, it moves from more concentrated to more diffuse forms over time, so everything you do with energy has a price tag, measured in a loss of concentration.

The ecosystem receives almost all of its energy from the sun.

In energy terms for instance, a garden bed is a device for collecting solar energy by way of the biochemical dance of photosynthesis. […] Most of the energy is used by the plants to draw water up from the ground and expel it as water vapor into the air; a few percent is caught by chloroplasts–tiny green disks inside the cells of every green plant–and used to turn water and carbon dioxide into sugars, which are rich in chemical energy and power the complex cascade of process we call life.

Most of those sugars are used up keeping the plant alive. The rest are stored for the plant’s future needs, though a percentage of them get hijacked if some animal eats the plant. Most of the energy in the plants the animal eats gets used up keeping the animal alive; the rest get stored until another animal eats the first animal, and the process repeats. Sooner or later, an animal manages to die without immediately ending up in something else’s stomach, and its body becomes a lunch counter for all the creatures–and there are a lot of them–that make a living by cleaning up dead things. By the time they’re finished with their work, the last of the energy from the original beam of sunlight that fell on the garden bed has been lost to the food chain.
What happens to it then? It turns into diffuse background heat. That’s the elephant’s graveyard of thermodynamics, the place useful energy goes to die. When you do anything with energy–concentrate it, move it, change its form–a price has to be paid in diffuse heat. All along the chain from the sunlight first hitting the leaf to the last bacterium munching on the last scrap of dead fox, what isn’t passed onward is turned directly or indirectly into heat so diffuse that it can’t be made to do any work other than jiggling molecules a little.

Over a long period of time, some of the energy stored by organic processes was converted into the very high energy density form of oil and other fossil fuels. It is these stores of energy that fuel the entirety of the Industrial world.

Contrast heating your water with natural gas to “a solar water heater, the simple kind that’s basically a tank in a glassed-in enclosure set on top of someone’s roof.” The former is dependent on a fossil-fueled powered global supply chain, the latter requires some glass and a metal tank. A characteristic of appropriate technology is that it is resistant to global failures.

Natural systems, having had much more time to work the bugs out, are much better at containing and using energy than most human systems are. […] By using existing natural systems to do things, green wizards can take advantage of two billion years of evolution, and by paying close attention to the ways that natural systems do things, green wizards can get hints that will make human systems less wasteful.

Energy doesn’t move in circles. Next lesson, we’ll be talking about material substances, which do follow circular paths; in fact, they do this whether we want them to do so or not, which is why the toxic waste we dump into the environment ends up circling back around into our food and water supply. Energy, though, follows a trajectory with a beginning and an end. The beginning is always a concentrated source, which again is almost always the sun; the end is diffuse heat. Conceptually, you can think of energy as moving in straight lines, cutting across the circles of matter and the far more complex patterns of information gain and loss. Once a given amount of energy has followed its trajectory to the endpoint, for all practical purposes, it’s gone; it still exists, but the only work it’s capable of doing is making molecules vibrate at whatever the ambient temperature happens to be.

While energy is the capacity to do work, it can’t do work in a vacuum. To make energy do whatever work you have in mind for it–whether that work consists of growing plants, heating water, or anything else–matter, information, and additional energy have to be invested. The plant needs carbon dioxide, water, and an assortment of minerals, as well as the information in its DNA and a stock of energy stored up in sugars from previous sunlight, in order to turn each new photon into useful energy. The solar water heater has equivalent requirements.

Energy is finite. It’s common for people these days to insist that energy is infinite, with the implication that human beings can walk off with as much of it as they wish. This is an appealing fantasy, flattering to our collective ego, and it plays a central role in backing our culture’s myths of perpetual technological progress and limitless economic growth.

Useful energy is always limited, and it usually needs to be coaxed into doing as much work as you want to get done before it gets away from you and turns into diffuse background heat.


Of the three factors that flow through every whole system–energy, matter, and information–matter is the messiest. […] Matter moves in circles, especially when you don’t want it to do so. […] Dilute an environmental toxin all you want, and it’s a safe bet that a food chain somewhere will concentrate it right back up for you and serve it on your plate for breakfast.

It’s hard to think of anything more dilute than the strontium-90 dust that was blasted into the upper atmosphere by nuclear testing and scattered around the globe by high-level winds; that didn’t keep it from building up to dangerous levels in cow’s milk, and shortly thereafter, in children’s bones.

There is no magic Away. Waste does not go to a magical place when it leaves your sight, it just moves elsewhere. You cannot stop it from circling back to you!

I hope I won’t offend anyone’s delicate sensibilities by using using human feces as an example. The way we handle our feces in most American communities is frankly bizarre; we defecate in clean drinking water, for heaven’s sake, and then flush it down a pipe without the least thought of where it’s going. Where it’s going, most of the time, is into a river, a lake, or the ocean, and even after sewage treatment, you can be sure that most of what’s in your bowel movements is going to land up in the biosphere pretty much unchanged because mushing feces up in water and then dumping some chlorine into the resulting mess doesn’t change them enough to make a difference.
Consider the alternative of a composting toilet and a backyard garden. Instead of dumping feces into drinking water, you feed them to hungry thermophilic bacteria. When the bacteria get through with the result, you put the compost into the middle of your main compost pile, where it feeds a more diverse ecosystem of microbes, worms, insects, fungi, and the like. When those organisms are done with it, you dig the completely transformed compost into your garden, and soil organisms and the roots of your garden plants have at it. When you pick an ear of corn from your garden, some of the nutrients in the corn got there by way of your toilet, but you don’t have to worry about that. The pathogenic bacteria that make feces dangerous to human beings, having grown up in the cozily sheltered setting of your gowels, don’t survive long in the Darwinian environment of a composting toilet, and any last stragglers get mopped up in the even more ruthless ecosystem of the compost pile.

If that’s a bit much for you, consider composting your left-over vegetables, egg shells, and the like.

One of the essential boundaries of appropriate tech is the boundary between the kinds of matter you can change with the tools you have on hand, and the kinds you can’t, and if you can’t change it into something safe, it’s a bad idea to produce it in the first place.


The entire notion of the Singularity is rooted in a basic misunderstanding of what information is and what it does. This is all the more embarrassing in that this misunderstanding was dealt with conclusively decades ago by the pioneering theorists of cybernetics. Gregory Bateson was one of those pioneers, and his work is a good place to start cleaning up that mess. Bateson defines information as “a difference that makes a difference.” This is a subtle definition, much more subtle than it seems at first glance, and it implies much more than it states. Notice in particular that whether something “makes a difference” is not an objective quality possessed by a difference; it depends on an observer, to whom the difference makes a difference. To make the same point in the language of philosophy, information can’t be separated from intentionality.

This observer-centered definition of information is key! Shannon Information is objective for a given probability distribution, but this probability distribution is given by an observer (or better: an actor.) We transmit symbols for a reason, there is a purpose behind it. The focus on processing power without focus on intentionality has led to a world where it takes 700 MB to run a chat program so that they can charge you for emoticons.

The torrent of raw difference that deluges every human being during every waking second, in other words, is not information. That torrent is data–a Latin word that means “that which is given.” Only when we approach data with intentionality, looking for differences that make a difference to us at that moment, does data become information–also a Latin word, meaning “that which puts form into something.” Data that isn’t relevant to a given intentionality, such as the dirt on a window when you’re trying to see what’s outside, has a different name: noise.
Thus the mass production of data in which true believers in the Singularity place their hopes of salvation is much more likely to have the opposite of the effect they claim for it. Information only comes into being when data is approached from within a given intentionality, so it’s nonsense to speak of it as increasing exponentially in any objective sense. Data can increase exponentially, to be sure, but this simply increases the amount of noise that has to be filtered before information can be made from it. This is particularly true in that a very large portion of the data that’s exponentially increasing these days consists of such important material as, say, internet gossip about the current color of Lady Gaga’s pubic hair.
Data, in other words, must be filtered in order to turn it into information. The process of filtering data to produce information and get rid of noise, in turn, always requires energy, matter, and additional information. Like energy and matter, information doesn’t function in a vacuum; whether the information is in a plant’s DNA, a human brain, or an electronic device, it has to be stored in matter, by the application of some kind of energy, using some additional set of information that governs how it is encoded. As with energy and matter, in turn, it’s usually these additional factors that impose hard limits on the kinds and amounts of information that can be used in any given situation.

What is information for one person may be noise for another. Information processing only increases if we get more out of it. Have we gained anything from letting the media beam their thoughts onto your screen at all times? If you disagree with their intent it’s all noise!

As a green wizard, your goal in crafting systems is to come up with stable, reliable information filters that will pursue their own intentionalities without your interference most of the time, while you monitor the overall output of the system and keep tabs on the very modest range of data that will let you know if something has gone haywire.

Humans have an inherent notion of quality, or what matters. This cannot be replaced by a machine! A machine is an artifact, a tool, it has no experience of quality. Humans are the ultimate arbiter because they experience the good!