What is the Essence of Computing?

One of the most important lessons I learned in my physics education was this: whenever approaching a problem, first ask yourself, “What is the essence of the problem?” Dig down deep, toss aside all the secondary factors and zero in on the central issue, the heart of the problem. The harsh discipline of physics drove that skill into my skull.

It might seem silly to ask “What is the essence of computing?”, but it is a question that deserves an answer — and just now, there really aren’t many people who can answer it, because the answer involves some quite abstract concepts: the difference between objects and processes.

The Great Dichotomy
Here we come to the deepest and most important realization of my life. It can be expressed in a simple question:

Is reality a collection of objects or a system of processes?

This question shows up over and over in many fields of human inquiry, taking a different form in each. (Auto-back-patting moment: this is one benefit of a broad education. Most intellectuals are by necessity specialists, becoming very good in a single subject. Unconstrained by this necessity, I have been able to study anything that struck my fancy, and my omniverous curiosity allowed me to see connections between multiple fields that would be unnoticed by specialists.)

Physics
Let’s begin with physics. A fundamental dichotomy shows up in physics, between particles (objects) and waves (processes). Right up until the beginning of the twentieth century, physicists treated these two as independant realms. They could solve all sorts of problems involving particles using regular laws of mechanics: Newton’s Laws, conservation of energy, momentum, and angular momentum, and so forth. For waves, they had a completely different mathematical approach, which was also highly effective.

Without going into the fascinating details of the history of physics, I’ll simply say that, early in the twentieth century, physicists realized that, at the subatomic level, particles and waves merged. A photon, for example, behaved like a wave and also behaved like a particle. The distinction arose only from the way you measured it. With one type of experiment, it acted like a wave; in another experiment rigged for particles, it acted like a particle. It was both wave and particle: a “wavicle”. Eventually they established that everything in the universe is a wavicle. But massive particles like stars have extremely short wavelengths, and waves with very long wavelengths acted almost entirely like waves. This “wave-particle duality” is now part of fundamental physics.

Interestingly, the Heisenberg Uncertainy Principle can be expressed in wavelike terms or particle-like terms. If you want to apply it to a particle, you use this form:

∆p * ∆x ≥ h

Translation: the uncertainty in the measurement of a particle’s momentum multiplied by the uncertainty in the particle’s measured position is always greater than or equal to the Heisenberg constant h, which is 6.62 * 10^-34 Joule-seconds.

But there’s another form that expresses the same idea in terms more fitting for waves:

∆E * ∆t ≥ h

Translation: the uncertainty in the measurement of the energy of an event multiplied by the uncertainty in the measurement of the time of the event is always greater than or equal to the Heisenberg constant h. Note that this version of the Uncertainty Principle concerns energy and time — that’s significant.

Economics: As you learned in high school, the two classes of economic output are 1) goods and 2) services. Good are objects; services are processes.

Computers: The distinction is absolutely clear with computers. Data are or describe objects; programs are processes.

Linguistics: There are two fundamental classes of words: nouns and verbs. Nouns specify objects; verbs specify processes. Every sentence must contain at least one noun and at least one verb.

Military Science: The study of military science focuses on two factors: assets (guns, tanks, planes, soldiers) and operations (maneuvering them around). Assets are objects; operations are processes.

Thus, reality is composed of objects and processes. But there’s a tricky catch: objects blur into processes; sometimes you can’t tell whether something is an object or a process. We encountered this with physics, in which particles (objects) can, under appropriate circumstances, behave like waves, and vice versa. So is a photon a particle or a wave?

In economics, the blurring between object and process can be even more confusing. When you purchase a hamburger, are you buying an object or a process? The knee-jerk answer is “object”, but consider this: are you not paying for the services of the person who takes your order, the person who cooks the meat, the person who drove the truck that brought the food to the restaurant, and the person who raised the cattle, grew the wheat, and so on? Is a hamburger a good or a service? It’s hard to say.

What is the essence of computing?
Now at long last I can return to the original question posed in this essay: what is the essence of computing? If you ask the average person to point to their computer, they’ll probably point at the monitor:

Har de har — people are so dumb! You and I know perfectly well that the computer is the big box that hums:

And in fact, when pressed, you’ll admit that the heart of the computer is in fact the CPU:

CPU stands for Central Processing Unit. Can you guess what it does?

Thus, the heart of any computer is a processing machine. That is the very essence of computing: processing. Just as every sentence must have a noun and a verb, any useful program must contain both data and processing. But the processing part is where the magic happens.

Next up: Why we don’t understand computers.