Is everything a form of computation? That’s what some scientists are saying. I found the CACM article “Computing is a Natural Science”, by Peter Denning on reddit recently. I looked at the title and thought, “Yeah, so?” When I took computer science at Colorado State University 14 years ago it was in the College of Natural Sciences. At some universities it was in the College of Engineering. I don’t think it got to where it was at my school because the faculty was being extraordinarily perceptive. I don’t remember my teachers talking about this concept that natural processes are being “computed”. Mathematics was in the Natural Sciences college as well. Computer science is historically an offshoot of mathematics. So it follows that it would be in the same college.

Anyway, at first glance I thought the article was trying to make a provocative argument that CS *should* be in the Natural Sciences college…and perhaps it should. The article is deeper than it appeared. Mark Guzdial gave a good analysis of it (**Update **5-24-2013: the blog where he wrote this has disappeared), so I won’t repeat it here. This quote from it is a good summary:

Peter [Denning] makes the point that scientists are discovering that much of nature is about information processing. Books like Stephen Wolfram’s

A New Kind of Sciencemake the point that algorithms underlie much of nature–“nature is written in the language of computation, challenging Galileo’s claim that it is written in mathematics.” Thus, studying computing is studying nature.I highly recommend the article. I particularly like his conclusion where he points out, “Computing is no longer a science ofjustthe artificial [my emphasis]. It is the study of information processes, natural and artificial.”

It dovetails into something he’s been talking about for a while, that CS is branching out and being adopted by other disciplines, such as the sciences. For example, programming is being taught in physics classes at some universities now. Students are expected to write programs related to the material as part of the course.

The CACM article reminds me of one I heard about in Scientific American a while back. Someone published a theory a few years ago saying that the universe is actually a holographic computer (just linking to this for the summary).

In the next part I’ll discuss a speech that Alan Kay gave 10 years ago where he makes the same points in regards to molecular biology. I’m speculating, but it’s not too difficult to believe that Kay figured out there is computation going on inside of biological cells more than 30 years ago when he developed OOP and Smalltalk, perhaps before then. As he conceived it, OOP uses biological metaphores.

I can understand the notion of biological computation. Once you see how Kay explains it, I think it’ll make sense to you as well. I guess this makes sense for the other fields of science if you view computation as just a series of predictable and quantifiable stimuli and responses, where the responses follow discernable rules.

I wrote an extensive reply to the ACM article at reddit. To give a brief summary, I think the claims of the article are either trivial, unproven, or nonsensical depending on how you interpret it:

1) Trivial. If the article is just saying, “Hey, computers are quite useful for doing scientific research” then duh.

2) Unproven. If the article is claiming that at the fundamental level, the universe is governed by Wolfram-style automaton rules, then this is a scientific claim that needs evidence to support it. So far, what Wolfram has said can be characterized as a hypothesis that we will someday find automaton rules that can describe the fundamental behavior of the universe. However, so far, no one has described such an automaton or shown that its predictions are better than those made using conventional mathematics.*

3) Nonsensical. If the article is claiming that at a fundamental level, the universe is merely a computation with no substance behind it, then I believe the claim is nonsensical. In our normal experience, a computation is a process whereby one rule governed system (typically a physical one) is used to make reliable inferences about another rule governed system (typically a mathematical one). If the universe is a computation with no computer, then it is computation unlike any that we are familiar with, since it lacks any one “real” system that can be correlated to the other inferred system. Rather, the inference is our universe, but the ground of the inference is empty. I cannot completely rule this out as a metaphysical possibility, but I do think that since it is so unlike any computation with which we have experience, it is stretching a point to call the operation of the universe a “computation” instead of “a system that can be accurately predicted by mathematical models that work in a computational (that is to say, iterative/recursive) manner .”

*I also have a problem with the idea that computing and mathematics are fundamentally different activities. In my view, computation is a branch of math.

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@Carl:

The article does say a bit about how computing is useful to science, but that’s not really what it’s about. What it’s saying is that computational processes are being found in other fields, like biology, even physics (at the quantum level). Biology I can buy, as my 2nd part to this will illustrate some. The ACM article goes a bit into how computing is being found in other fields besides the traditional sciences.

Re: #2

I think you’re referring to the Scientific American article here. To tell you the truth, I didn’t understand much of it, and I didn’t finish reading it. The concept seemed kind of far out. Just thought I’d mention it since this idea was not mentioned in the ACM article, except to mention a principle or two of quantum physics (the physics of the very small).

As to computing and mathematics, I’ll get to this in my 2nd part. I think Wolfram was being imprecise in that quote. I think he was talking about what’s been termed “classical mathematics”, like Calculus, which has an unbounded, almost unquantifiable quality, especially since it uses the concept of infinity–something that cannot be measured. Certainly computation does involve math, but chiefly finite forms of math.

Re: #3

Referring to the ACM article, it talks chiefly about “computation in nature”, and in other fields of study, not the universe as a whole. Maybe Wolfram talks about that in his book. I haven’t read it.

I think what the article is really getting at is that observing nature can be like observing a computer in operation (using a rough analogy). So it can be observed and discussed in computational terms. I think your last quote sums up the article well: “a system that can be accurately predicted by mathematical models that work in a computational (that is to say, iterative/recursive) manner .” The whole point of it was to say that computation is being

observedin natural processes. I don’t think it’s saying at all that we understand the inferences in total.In a metaphysical way, one could refer back to the “Hitchhiker’s Guide to the Galaxy” series, by Douglas Adams, a comedic romp that concluded that the Earth and its inhabitants were part of a cosmic “Jeopardy” game. Some people on some planet asked a massive computer, “What’s the meaning of life?” The computer took decades to come up with the answer, “42”. The questioners asked, “42?? What does that mean?” And so Earth was created as a giant computer to figure out the question to the answer. I dunno. Things like this pop into my head sometimes. 🙂

There was a throw-away line in the article that I think is really significant: “Computing interacts constantly with other fields. The other fields teach us more about computing”. This plays a major part in the next post I’m writing up about this subject.

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Thanks for your indepth response. Re: point 3, yes, I acknowledge that anything, even the Earth itself as a whole, can be used to perform a calculation. I guess my beef with supposing the universe as a whole is a “computer” is the neo-Pythagorean idea that there can be calculation without a substrate to the calculation. That is, the Pythagoreans said, “Everything is math; fire is just a bunch of triangles; etc.” The neo-Pythagoerans say, “Everything is discrete math; sub-atomic particles are just variables inside a program; etc.” However, it completely cuts against our experience to have a variable (a sub-atomic particle) that is not being represented by something else. Eg. If you do math on an abacus, one bead represents the variable of your current computation. If you do math on a computer, an electrical charge represents your current computation. But if the universe is a computer what is it that is representing the calculation being done by the universe? Nothing at all; it’s just a fundamental reality. I object to this, on the grounds that it is dissimilar to all other forms of calculation with which we are familiar. It might be true that the universe is ultimately empty (as the Tibetan Buddhists in fact claim), but it’s not right to call this claim “computation.”

Anyhow, this is just my incredibly technical nitpick as a philosophy grad student. Feel free to disregard it.