Ruliology is taking off! And more and more people are talking about it. But what is ruliology? Since I invented the term, I decided I should write something to explain it. But then I realized: I actually already wrote something back in 2021 when I first invented the term. What I wrote back then was part of something longer. But here now is the part that explains ruliology:
If one sets up a system to follow a particular set of simple rules, what will the system do? Or, put another way, how do all those simple programs out there in the computational universe of possible programs behave?
These are pure, abstract questions of basic science. They’re questions one’s led to ask when one’s operating in the computational paradigm that I describe in A New Kind of Science. But at some level they’re questions about the specific science of what abstract rules (that we can describe as programs) do.
What is that science? It’s not computer science, because that would be about programs we construct for particular purposes, rather than ones that are just “out there in the wilds of the computational universe”. It’s not (as such) mathematics, because it’s all about “seeing what rules do” rather than finding frameworks in which things can be proved. And in the end, it’s clear it’s actually a new science—that’s rich and broad, and that I, at least, have had the pleasure of practicing for forty years.
But what should this science be called? I’ve wondered about this for decades. I’ve filled so many pages with possible names. Could it be based on Greek or Latin words associated with rules? Those are arch- and reg-: very well-trafficked roots. What about words associated with computation? That’d be logis- or calc-. None of these seem to work. But—in something akin to the process of metamodeling—we can ask: What is the essence of what we want to communicate in the word?
It’s all about studying rules, and what their consequences are. So why not the simple and obvious “ruliology”? Yes, it’s a new and slightly unusual-sounding word. But I think it does well at communicating what this science that I’ve enjoyed for so long is about. And I, for one, will be pleased to call myself a “ruliologist”.
But what is ruliology really about? It’s a pure, basic science—and a very clean and precise one. It’s about setting up abstract rules, and then seeing what they do. There’s no “wiggle room”. No issue with “reproducibility”. You run a rule, and it does what it does. The same every time.
What does the rule 73 cellular automaton starting from a single black cell do? What does some particular Turing machine do? What about some particular multiway string substitution system? These are specific questions of ruliology.
At first you might just do the computation, and visualize the result. But maybe you notice some particular feature. And then you can use whatever methods it takes to get a specific ruliological result—and to establish, for example, that in the rule 73 pattern, black cells appear only in odd-length blocks.
Ruliology tends to start with specific cases of specific rules. But then it generalizes, looking at broader ranges of cases for a particular rule, or whole classes of rules. And it always has concrete things to do—visualizing behavior, measuring specific features, and so on.
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