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Linch's avatar

Detailed comment by someone on Facebook:

(sorry, for some reason substack won't let me post a comment on your blog, so I'll have to respond to your essay here.)

The anthropic principle is an interesting and fresh answer to the problem of the unreasonable effectiveness of mathematics. You are a very creative thinker.

Here are a few things which you might want to think about:

1. Is Math really that effective? When I was a geeky teenager, I knew a lot of math, but no matter how much I learned, I couldn't get cheerleaders to date me. There is a lot in our lives which we have no way to model mathematically.

2. As an engineer, sure, I use math. But I almost never use, say, math from the laws of physics on up. Much more frequently, I use formulas which I know *for sure* are wrong, but are nevertheless close enough approximations.

3. As a computer scientist, I did a lot of programming finding approximate solutions to NP-hard problems. There are even computer science problems we can prove have no mathematical solution. Knuth famously ended one of his papers with "I don't know whether this algorithm works or not; I haven't implemented it, I've only proved it correct." 🙂 Even in computer science, we can trust our models only insofar as they bear out in practice.

Now for a few more probing questions:

1. Suppose we lived in a universe which was a physicist's nightmare, but an engineer's heaven 🙂 I.e. there really were no laws of nature. Nothing really held true at all times and places. Nevertheless, engineers could gradually accumulate a grab bag of techniques, some resembling mathematics, some resembling poetry, some which resembled worship of a god or gods, etc, which eventually lead them to possess a civilization not unlike our own. What would your counterpart say in such a universe? Would he be able to advert to the anthropic principle as well to justify how his engineers were able to do their thing?

2. Imagine a universe which was created by a benevolent deity, ordered such that there were mathematical laws, and populated by creatures who could do math and find out these laws. What would your counterpart say to justify the existence of that universe? Could you even prove that *this* universe is not such a universe?

Now for some brief observations of my own as to why math is so effective.

1. Let's start with what we mean by a law of nature. Best answer I could find is something like a) it hold at all times in all places, under all circumstances, i.e. it is utterly exceptionalness, and b) any two observers will be able to agree that those laws hold.

2. Unpacking the agreement among agents, at the very least, if two agents are to agree on something, that something has to be *communicatable* from one agent to the other. Which means that it has to be expressible in a language which both agents can understand and agree on the meaning of the messages expressed in that language--in particular, they need to be able to agree that they can refer to the same object or situation.

3. Unpacking communicable: what are the conditions under which a language is communicatcble: the best answer to this question was given IMHO by Turing, in his original paper where he introduces the Turing machine. For space reasons I can't put his full argument here (I do recommend the paper to you if you haven't read it! It's marvelous). Turing had to formalize a notion of communicatability in order to argue that his machines were indeed could do any possible computation. Namely, the symbols on the tape, and the symbols used to represent the states of the machine, must be communicatable because, really, when a machine goes from state to state, it is communicating with itself as to where it is in the computation.

Bad description--pleae read Turing's paper if that isn't clear.

4. So lets telescope back: For something to be a law, any two observers must agree that it holds everywhere excepitionlessly. For them to agree, they have to communicate. For them to communicate, they must share a language which is computable. And that's where the math comes in: computation is just math in action, as it were.

5. So that's why math is all over the place: anything we can communicate with each other, anything we can agree on--or even specify with enough exactness to be able to disagree about, must be expressed in a computable language.

Thanks again for the very enjoyable essay.

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Lukas Hager's avatar

This is a fascinating post. I am a huge believer in a deep biological origin of mathematics. Specifically, the emergent complexity of biological systems is one of many ways in which our mathematical system of logic seems to build itself.

Life started out in small havens of predictable sources of chemical complexity (primordial deep sea vents). From there, life began to colonize the rest of the world through a process of biological evolution and ecosystem engineering — e.g. photosynthesizers stabilizing our atmosphere over time, forests creating their own ideal growing conditions.

This process is pretty analogous to the semantic colonization of our world by rationalist societies. Math started out in controlled, predictable corners (like Euclidean geometry) and was built and expanded to cover any practicable area. You are right that math proved surprisingly able to predict many unrelated aspects of our universe, just as life proved capable of colonization many surprising niches.

One thing you are missing though is that math, like organic life, creates many of its own areas of application. For example, our financial system emerged and dominated in its current form because that is the form that allows clear and simple analysis by mathematics. However, not every aspect of our universe is equal in this regard. Quantum mechanics is starkly concise in mathematics, and biological life has no real effect on that (quantum Darwinism is an interesting theory related to that though). On the flip side, day to day weather events are still entirely unpredictable and mathematically ugly. The process of biological and financial evolution is mainly the expansion of semantics into these frontiers, and the logical corrections needed to maintain systemic consistency.

In short, complex life and mathematical reason both originate in small havens of predictability and reason. They then spread into available areas of logical consistency through evolution, or create new pockets through semantic colonization.

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