The subject of complexity stimulates lots of questions. To list a few: Why do many complex things seem to have a purpose or to fit to something else in a nontrivial way? Are complex objects different in some fundamental way from simpler objects? How are great complexities even theoretically possible? And how do things that give the appearance of wild improbability actually come about? Answering these and other questions is what motivated me to research and write this book. As I read what others have said and refined my own understanding, I found it impossible to ignore the underlying mechanism...

Imagine you are an intergalactic scientist observing our world. Your instruments tell you the atmosphere is wildly out of chemical equilibrium with too much oxygen and too little carbon dioxide. Sister planet Venus, in contrast, has 20,000 times more carbon dioxide and no free oxygen in its atmosphere. Earth also emits complex radio signals at many different wavelengths, and parts of its surface give off light at night even though the surface is not hot enough to cause rocks to glow. A closer inspection reveals narrow strips of concrete thousands of miles long, skyscrapers, and ecosystems dominated by rows of...

Listen to music or surf the Internet on your iPad. Start your car in the morning without touching the accelerator pedal and your engine “decides” how much gasoline and air flow into the cylinders; as the engine warms, the ratio of gas and air changes. Step on the accelerator and the ratio changes again. How are such things possible? Electronic computers function in each device. It is pretty hard these days to escape the influence of computers. They calculate our bills, produce photographs without film, keep track of your likes and dislikes, and predict the weather. Computers are machines that...

Imagine a water molecule floating around in the atmosphere, freely moving this way and that until by pure happenstance it encounters a growing snowflake. Depending on the angle of approach, it sticks like a fly to flypaper, or it bounces off, continuing on its way. This seemingly haphazard process when repeated over and over builds a beautiful and regular structure. Think of a river flowing over a mossy rock. Water molecules in uncountable numbers interact, this time to form eddies spinning their way down the stream. Now imagine the grand sweep of a vastly large but wispy cloud of hydrogen...

Imagine yourself to be an inventor and entrepreneur who comes up with an idea for a widget. You make a prototype out of string and carved pieces of wood, and it looks like it might work. How do you go about producing thousands of widgets made of aluminum and plastic that you can sell to eager widget buyers? You don’t hire a theoretical computer scientist to design simple parts that when shaken together will spontaneously form completed widgets. Nor do you hire a nano-engineer to design microscopic robots that when programmed with simple rules can be set loose in a...

Remember predigital television sets? I still use one. When I turn to a channel having no nearby transmitter, the screen exhibits “snow,” a random flickering of pixels. Dialing to another channel, I see actors performing or scenes of faraway places. The difference between disorder and order on the screen is clear. The snowy screen has the same number of pixels as the screen showing a talking head, but they are arranged differently. Salt crystals, viruses, and action potentials provide examples of order found in nature; gases and liquids lack structure. When the parts (pixels or molecules) have relationships to one...

Texting on some cell phones can be pretty tedious. To make it easier, phones often include a feature that guesses the word you are typing. The more you use it, the better the phone’s ability to guess correctly. It does this by learning your habits. Computer scientists have devised a variety of techniques that allow computers to learn. Many of these employ variations on the engine of complexity. In the world of living beings, evolution results in the accumulation of information about the environment—the system learns. Natural selection when provided small random DNA sequence changes picks those that produce...

Picture yourself in Paris. Most tourists to the City of Light spend a day or more at the Louvre. In the Greek and Roman antiquities section of the museum around the corner from the more famous Venus de Milo, at the head of the Daru staircase is a magnificent sculpture called the Winged Victory of Samothrace. The figure, even missing head and arms, is stunning. How did the sculptor do it? I am told that great artists see clearly in their heads what the final product will look like. The mental image serves as a blueprint, but how does that...

The formation of body and brain during human development is impressive. It demonstrates the creative potential of a physical system capable of generating variations, selecting some, and building new structure on that selected. But this strategy does have limits. There are many things in the physical domain that cannot be achieved so simply. This is why instruction use is so important in our world. Recall that essentially anything in the physical domain is achievable if the proper instructions can be obtained and employed. The engine of complexity operates at the level of instructions. By applying to instructions the basic principle...

There is no widely accepted mathematical definition of a complex system. Computers, thunderstorms, the human brain, and corporations are all examples. Always they are made up of many parts interacting with one another in specific ways. Outcomes of these interactions are often hard to predict. Since one of my goals is to explain the existence of complex objects (and there is no clear distinction between an object and a system), it seems appropriate to examine a few such systems in greater detail. Clearly, the opportunity for a system to exhibit complex behavior must be greater when there are more parts....

Picture yourself on a tropical beach with blue sky overhead, wind rustling in the palm trees, waves breaking, and white sand squishing between your toes. It’s easy; anyone who has been to a beach can do it. This same capability allows mathematicians to prove theorems and sculptors to envision a finished statue in a block of marble. The mind is the greatest of all intellectual challenges to understand. It has been a subject of philosophical discourse for as long as there has been writing, and few great thinkers have failed to weigh in on the subject. By studying the brain,...

Human culture, as distinct from chimpanzee or ant culture, is made possible by human language. Beethoven symphonies, corner drug stores, presidential elections, the Roman Catholic Church, and baseball games all depend on language. Sophisticated language allows us to share complex ideas and knowledge with others. From a computational perspective, communication consists of transmitted and received information, and whenever a chunk of information is communicated widely among members of a society, we recognize it as being part of culture. A culture, then, is the outcome of many remembered communications. Animals communicate, but the amount of information they exchange is much more...

The perception that evolutionary change produces ever-increasing complexity is deeply ingrained in Western culture. There are some valid reasons for this, but scientific opinions about whether or not it is true differ, and the matter remains unresolved. On one side are incredible advances in science and technology and also the broad sweep of life beginning from simple chemical mixtures that eventually yielded self-aware human beings. These examples suggest the action of some inexorable drive that generates more and more complexity. On the other side of the argument are observations that many biological lineages do not generate any obvious complexity increases...

The two most frequently asked questions I get from students who are first learning about evolution are: How did life start? And, what is its future? These are hard questions. The engine-of-complexity concept provides added perspective to both. I will start with origins.

If you think back, we have considered four examples of the engine of complexity operating today on Earth: life, the mammalian adaptive immune system, social change (with religion, science and technology, and the economy as subexamples), and evolutionary computer algorithms; with human learning presenting a possible fifth example. Every implementation of the engine requires a physical system...

Futurists have a terrible record of predicting the future. There is a good reason for this. A central feature of the engine of complexity is that trajectories of outcomes through possibility space are chaotic in the sense that there is no way to predict in detail where they will go. This reflects the underlying source of creativity, random change; still, predicting the future is a fun thing to do. When a system is characterized by an optimum, engine-of-complexity-based changes will home in on that perfect solution; but even in those cases, paths to the predictable outcome are unpredictable. Think back...