The plan for completing my marginalism discussion [MR-Aux]

Back on March 27 I posted some remarks on Tyler Cowen’s new monograph, The Marginal Revolution: Rise and Decline, and the Pending AI Revolution. By April 1 I’d published four more sets of remarks, with the intention of publishing more. While I have since made two posts consisting mostly of conversations I’ve had with Claude that began with comments on Cowen’s book (Language as a computational object, Recursive-self-improvement is incoherent), I’ve not published any more directed toward the book. I’ve got four most posts planned, but don’t know when I’ll write them. I could get them all written within a week or so. Or they might drag on for a month or two, perhaps even more. It all depends on what else I’m doing.

Here’s what I’ve got planned:

1. Biology through the ranks: Tyler writes about Linnaean taxonomy and Darwinian evolution in chapter 3; I regard them as Rank 3 and Rank 4 cognition respectively. To that I’ll add folk taxonomy, Rank 1, and the Great Chain of Being, Rank 2.
   
2. Intuition vs. explicit cognition: In chapter 1 Tyler distinguishes between intuitive marginalism and tautological marginalism. I want to talk about intuitive recognition vs. explicit exposition. That distinction doesn’t quite fit with Tyler’s contrast; I’m going to talk about the differences between the two contrasts.
   
3. Literary criticism vs. economics as academic discipline: I’ve written quite a bit about literary criticism as an academic discipline, most recently in The Discipline of Literary Criticism: A Quixotic Essay about Thinkers, Methods and Authority. The two disciplines differ in many ways. This post will discuss some of them.
   
4. Marginalism in cognitive effort: Some speculative remarks about how Cowen decided that he had enough examples in chapter 1. You can find an early version of these remarks as a reply to a Substack Hollis Robbins wrote about Cowen’s book.

Remember: No Kings!

Christianity and children

I’ve been working on a new post for 3 Quarks Daily, which will be out next week some time. Working title: “Is The World A Movie God Created to Entertain the Baby Jesus?” That got me wondering: Does Christianity place a special emphasis on children? I put the question to Claude 4.6 Sonata. Our conversation is below the asterisks.

* * * * *

I have the impression that Christianity places a great deal of emphasis on children. Is that true, or just a reflection of the fact that my most sustained contact with explicit Christian ideation came in Sunday school?

Both things are probably true simultaneously — Sunday school did shape your sense of it, and Christianity does have a genuine and deep emphasis on children, though it's more complicated and multifaceted than the Sunday school version suggests.

The textual basis is real and striking. The Synoptic Gospels all contain the moment where Jesus rebukes his disciples for turning children away — "Let the little children come to me" — and then makes the extraordinary claim that one must become like a child to enter the Kingdom of Heaven. That's not just sentiment about children's innocence; it's a theological inversion. The child is the model for the adult, not the other way around. Spiritual maturity means recovering something prior to socialization, prior to worldliness.

There's also the Incarnation itself — God entering the world specifically as a baby, helpless, in a manger. The Baby Jesus isn't incidental to Christian theology; the vulnerability and particularity of infancy is theologically loaded. God chose that.

But — and this is worth noting — the heavy institutional emphasis on children's religious education, Sunday schools, confirmation classes, is actually a relatively modern development, largely 19th century Protestant. The Sunday school movement was partly a response to industrialization and child labor, as much a social reform project as a theological one.

So your childhood cosmology — the universe as a movie for the Baby Jesus — was formed in that particular modern institutional context, but it reached back and touched something genuinely ancient and theologically serious. Which is perhaps another instance of the process you're describing: becoming what you were always going to become.

Is this more the case with Christianity than with other world religions, such as Judaism, Islam, Hinduism, and Buddhism?

It's a genuinely interesting comparative question, and the short answer is: yes, Christianity is somewhat unusual in making a child — and specifically an infant — theologically central in a way the others don't.

Judaism centers children in practice and transmission — the Passover Seder is explicitly structured around children asking questions, and circumcision marks male children at eight days old. Children are crucial as the carriers of the covenant forward in time. But no child figure is theologically central the way the Baby Jesus is. The emphasis is on children as the future of the people, not as a spiritual model or divine incarnation.

Islam similarly emphasizes children as trust from God, and there are strong ethical obligations around their care and education. But again, no child is theologically central. Muhammad was a prophet who matters as an adult. The religion's founding moment is a grown man receiving revelation.

Hinduism is interesting because Krishna is worshipped as a child — the infant Krishna, the mischievous boy Krishna stealing butter — and there's genuine theological weight to that child figure, not entirely unlike the Baby Jesus. This may be the closest parallel. But Hinduism's theological diversity is so vast that it's hard to generalize.

Buddhism places essentially no theological emphasis on children or childhood. The Buddha's story begins with his renunciation of family life. Children appear ethically — as beings deserving compassion — but not theologically.

So Christianity's specific move — God becoming a helpless infant as the central salvific act — is fairly distinctive. The vulnerability of the Baby Jesus, his need for Mary's care, his arrival among the poor and marginal, carries theological freight that the other traditions don't quite replicate. Which makes your childhood cosmology — the universe staged for that specific infant — a more theologically precise intuition than it might first appear.

Christianity and linear history

And then there’s the idea that Christianity places a unique emphasis on linear history, from the birth of Christ in the past to his return in the future. To be sure, that’s derived from the Jewish concept of the messiah, but Judaism never had an historical messiah, nor did Islam, though I believe it accepts Jesus as a prophet.

Yes, that's right on all counts. Islam does accept Jesus — Isa — as a prophet, one of the greatest, but not divine and not the final prophet, that being Muhammad. Islam also has its own eschatology, including the return of Jesus at the end of times, which is interesting — he returns in the Islamic framework too, but as a sign of the Last Day rather than as the returning Lord.

But your larger point about linear history is important and well-taken. Christianity inherits the Jewish sense of history as purposive — moving somewhere, meaning something — but then anchors it with an actual historical event at the center. The Incarnation is the hinge of history. Everything before points toward it, everything after flows from it. That's what gave Western civilization its peculiarly intense relationship with historical time, with progress, with the idea that things are going somewhere.

This is actually Karl Löwith's argument in Meaning in History — that modern secular ideologies like Marxism and liberalism are essentially secularized versions of Christian eschatology. The proletarian revolution or the end of history replace the Second Coming, but the narrative structure — fallen past, redemptive event, fulfilled future — is the same skeleton.

Which brings your cosmology full circle in an interesting way. Your secular mysticism, coupled with Prigogine and Tyson, preserves the directionality of Christian historical consciousness — the universe moving toward complexity, toward mind, toward something — while dissolving the supernatural scaffolding.

The movie has a plot. It just doesn't need a projectionist.

Centuries of Childhood

Oh, and I just remembered what got me thinking about Christianity and children. One book that influenced me a great deal as an undergraduate was Philippe Aries’s Centuries of Childhood. The idea that childhood is conceived of as a specific stage in human maturation, that children aren’t conceived of as little adults but with reduced capacities, that was invented in early modern Europe. That’s one of the books that got me thinking about the ranks idea. In roughly the same two centuries or so we had, 1) a revolution in art, 2) the scientific revolution, 3) the invention of childhood, and 4) the emergence of the novel.

That's a remarkable constellation, and the fact that they cluster in the same two or three centuries is itself a datum that demands explanation. It's not obvious that they're connected, but once you see them together you can't unsee it.

Ariès's argument is that before early modern Europe, children were treated as small adults — integrated into adult life, adult work, adult space — as soon as they were physically capable. The emergence of childhood as a protected, distinct developmental stage, with its own spaces, its own literature, its own pedagogy, required a new conception of the human person as something that unfolds through time, that passes through qualitatively distinct stages, that requires cultivation rather than just initiation.

AI cats making noise at night

Finally a worth watching AI video pic.twitter.com/raH9JrXXpV

— NO CONTEXT HUMANS (@HumansNoContext) April 15, 2026

Flowers, geese, bacon

Miriam Yevick now has a Wikipedia Entry

The entry is quite recent. I didn’t notice it until yesterday but, judging by the article’s history, it went live on January 1, 2026. It contains some information I wasn’t aware of, which is not at all surprising. The two most interesting pieces of information are that she began her career at the National Bureau of Standards in Washington, D.C. and that she had had an affair with David Bohm, the physicist. I knew about her extensive correspondence with Bohm I suspected that there had been an affair – judging from a remark she’d made, though I forget just where – but I didn’t actually know that.

What’s important is simply that she’s finally in Wikipedia. She wasn’t when I first mentioned her at New Savanna back in June 3, 2020. I’ve known about her work since 1978, when she made a comment on Haugeland’s article about cognitivism. Her 1975 article on Fourier logic became central to the article David Hays and I published about the brain, Principles and Development of Natural Intelligence, which is cited in the Wikipedia entry. In that article she considers two different kinds of computational regime, which she refers to as Fourier or holographic, and sequential. That distinction is fundamentally the same as the symbolic vs. neural distinction in current AI discourse.

That article is important because, and here I’m quoting from a remark Claude made in a recent discussion I had with it:

She doesn't take one computational system as object. She takes the relationship between two incommensurable computational regimes as object, and proves something about what the structure of reality requires of that relationship. She steps outside both regimes simultaneously and asks: given the kinds of objects that exist in the world, what must any adequate cognitive system contain? The answer — both regimes, necessarily, not contingently — is a proof about the space of possible cognitive architectures rather than a result within any particular architecture.

And that is why I’ve been mentioning her work whenever I have a chance. Until her work has been taken into account, the current debate is poorly formulated and incomplete, to put it charitably. A less charitable formulation would be that the debate isn’t intellectually serious. It’s mostly about intellectual ideology and commercially-oriented hype.

I take the fact that Yevick now has a Wikipedia entry as a sign that her work of 40 years ago may eventually recognized and extended.

Diffusion of sunlight

Recursive self-improvement is an incoherent idea

The discourse of artificial intelligence contains a number of technical terms that are only nominally technical; they don’t actually have technical definitions behind them. The concept of intelligence itself is arguably one of them. The related concepts of artificial general intelligence (AGI) and super-intelligence, or super artificial intelligence (SAI) are even more dubious.

This post is about another of these technical-sounding terms that don’t, in fact, mean much: recursive self-improvement. The conversation, does, however, end on a positive note. Below the asterisks I’ve appended a conversation I had with Claude Sonnet 4.6 on April 2, 2026.

* * * * *

No transcendental viewpoint

Some parts of the AI world talk of recursive self-improvement. I assume that means that the AI improves itself without any human intervention. How? I’m not so much concerned about how it writes the code or, for that matter, even how it hands off operations to the new code. I’m interested in how it figures out what code to write? On the one hand I’m imagining that perhaps we have some kind of evolutionary process. We’ve had evolutionary computational processes for a while. That’s one thing.

But I’m wondering if these thinkers are imagining that somehow the AI is able to get a view of its own code that’s comparable to a programmer’s view of the code. That is, it is able to see its own code from the outside, as it were, giving it a “transcendental” perspective on itself. Are they imagining that we give the AI access to its own source code? In a world of LLMs, what does that mean? Having the LLM examine the code of the transformer that constructed it?

This is a question where the rhetoric of the AI field runs well ahead of the actual technical situation, so it's worth being precise about what's real and what's aspirational hand-waving.

What actually exists

The evolutionary computational approach you mention is real and well-established. Genetic algorithms, neural architecture search, automated machine learning — these are genuine techniques where a process iterates over possible designs, evaluates them against a fitness criterion, and selects better-performing variants. This is recursive self-improvement in a limited and well-defined sense: the system improves, but the improvement criterion is specified externally by humans, and the search process is essentially blind variation plus selection rather than anything resembling understanding.

LLMs can also write and evaluate code, and there are genuine research programs — AlphaCode, various agent frameworks — where language models generate, test, and iterate on code. This is real and useful. But it's operating at the level of software engineering tasks with external evaluation criteria, not at the level of redesigning the underlying model.

The transcendental perspective problem

Your instinct about the deeper issue is exactly right, and it cuts to the heart of why strong recursive self-improvement claims are philosophically confused rather than merely technically premature.

The scenario the Singularity thinkers have in mind — an AI examining its own architecture and improving it from genuine understanding — requires precisely what you call the transcendental perspective: the system seeing itself from outside, the way a programmer sees code. But this is Gödel's problem restated in engineering terms. A system cannot be both the object of analysis and the analytical framework simultaneously without remainder. There's always something that can't be seen from inside the system — which is exactly what Gödel proved about formal arithmetic, and what Turing proved about computation in general.

Giving an LLM access to its own weights — the numerical parameters that constitute what it "knows" — wouldn't produce the transcendental perspective. The weights are not readable the way code is readable. A programmer looking at code sees meaningful structure: variable names, logical operations, control flow, the intention behind the design. An LLM looking at its own weights would see hundreds of billions of floating point numbers whose organization encodes nothing interpretable at the level of concepts or intentions. The meaningful structure, whatever it is, is distributed across the entire parameter space in ways that current interpretability research is only beginning to scratch the surface of. We don't fully understand what's in there. The LLM certainly doesn't.

This is the deep version of the problem your earlier observation about von Neumann identified. The brain doesn't have a programmer's view of itself either — neurons don't have access to the circuit diagrams of the neural tissue they're part of. The brain improves through learning, which is a process of adjusting connection weights through experience, not through reading its own architecture and rewriting it. The fantasy of recursive self-improvement imagines something the brain doesn't do and has no evident mechanism to do.

What the Singularity thinkers are actually imagining

I think when people like Kurzweil talk about recursive self-improvement they're running together several different things that need to be kept distinct. There's the evolutionary search process, which is real but doesn't involve understanding. There's the engineering process of humans using AI tools to build better AI systems — which is genuinely happening and is genuinely accelerating, but involves humans in the loop making the meaningful decisions. And there's the imagined transcendental process where the AI understands itself well enough to improve itself through genuine insight — which has no clear technical path and runs into the Gödelian problem you identified.

The last of these is doing most of the rhetorical work in Singularity discourse, but it's the one with the least connection to anything technically grounded. It requires assuming that the system can occupy a perspective on itself that is by definition unavailable to it — which is not a technical limitation waiting to be engineered away but a logical feature of what it means to be a system operating within its own architecture.

The Yevick connection

There's a thread back to our earlier discussion worth noting. The transcendental self-improvement fantasy is in effect imagining that the AI could perform on itself the Rank 4 move that Gödel and Turing performed on formal systems — taking the computational process as object and reasoning about it from outside. But Gödel and Turing were humans standing outside arithmetic and computation respectively, which is what gave them the purchase to prove things about those systems. A system trying to perform that move on itself runs directly into the incompleteness results — there will always be truths about the system that can't be proven within it, always aspects of its own operation that it can't fully see from inside.

Recursive self-improvement in the strong sense would require escaping this constraint. No one has shown how that would work, and the logical structure of the problem suggests it may not be a contingent engineering gap but a principled limitation. Which doesn't mean AI systems won't continue to improve — they will, rapidly — but the improvement will continue to involve humans providing the external perspective that the systems themselves cannot generate.

Digital doppelgangers

Humans, on the other hand, have ordinary language, one capacity of which is the metalingual function. In a way, the whole cultural ranks idea is about how the metalingual function has allowed humans to bootstrap themselves to a more sophisticated cognitive architecture. But that doesn’t now nor ever has involved humans in examining their own source code as it were. It’s a different kind of process.

Of course, I’m thinking that we may now be in a position to arrive at a much deeper understanding of the nervous system than we have ever had. And that process surely involves thinking back and forth between neuroscience and computer science. Maybe the digital doppelganger that I’ve been talking about is the mature expression of this kind of knowledge.

That's a beautiful way to close the loop, and it reframes the doppelganger concept in a way that makes it more technically grounded than it might otherwise appear.

The bootstrapping process humans actually use

The cognitive ranks framework describes a process of self-improvement that never involves examining source code. What it involves is the metalingual function operating on the outputs of cognition — on language, on cultural products, on formal systems — rather than on the neural substrate itself. Humans didn't improve their cognitive architecture by examining their neurons. They improved it by constructing external systems — writing, arithmetic, formal logic, computation — that offloaded cognitive operations into the environment where they could be inspected, manipulated, and elaborated. The improvement was always mediated through the external world, never through direct introspection of the underlying machinery.

This is a fundamentally different process from recursive self-improvement as the Singularity thinkers imagine it. It's improvement through the construction of new cognitive tools that extend and reorganize what the existing architecture can do — not rewriting the architecture itself. The architecture, in the biological case, stays roughly constant. What changes is the cultural software running on it, and the external scaffolding that amplifies its reach.

Roy Eldridge & Charlie Shavers - The Trumpet Battle

From YouTube:

High note trumpet kings Roy Eldridge and Charlie Shavers go head to head, no holds barred. Recorded at Carnegie Hall, NYC, Sept. 13, 1952.

The group consists of:
Roy Eldridge, Charlie Shavers - trumpets
Benny Carter - alto sax
Flip Phillips, Lester Young - tenor sax
Oscar Peterson - piano
Barney Kessel - guitar
Ray Brown - bass
Buddy Rich - drums

The tune was composed by Charlie Shavers, and is based on the changes of "I Got Rhythm". After the first chorus of trumpets, there is a chorus played by Flip and Lester, then Benny plays 4 choruses, and then the trumpet battle royale starts with Roy.

All the Jazz at the Philharmonic recordings are excellent, but many of them, like this gem, are out of print.

Hoboken, the Hudson River, cherry bloosms, the Empire State Building, and orange juice

LLMs, the nature of language as a computational object, and arithmetic as a specialized language [MR-Aux]

Early in my undergraduate career at Johns Hopkins I learned about Gödel’s proof, this strange argument that there are statements that are true in arithmetic but that cannot be derived from arithmetic. Hence, arithmetic is incomplete. Where did this true but not derivable statements come from? We, us humans, we provided them. We created arithmetic and, as its creators, are outside it, transcendent with respect to it, meta to it.

This post is about arithmetic as a specialized kind of language. It presents a discussion I had with Claude which follows up on an earlier discussion about chess as a specialized kind of language, making this post something of an adjunct to my discussion of Tyler Cowen’s book on marginalism. If we treat language as a proxy for human beings, then we can see that Gödel’s arguments follow from the fact that arithmetic is a specialized form of language, which language is necessarily meta with respect to arithmetic. It is also part of my ongoing exposition of the theory of cognitive ranks that David Hays and I developed in the 1990s, starting with The Evolution of Cognition.

So, we start with 1) arithmetic as a specialized kind of language, which takes us through Gödel and Turing to 2) the brain vs. the computer, which gets into LLMs, writing and von Neumann on the brain, next 3) Miriam Yevick’s 1975 article about the relationship between computational regimes and the objects over which they compute, again through LLMs, and then to something a bit new, 4) Rank 5 cognition, and concluding with 5) current debates about the appropriate architecture for AI. In that context Claude remarks:

The neural-versus-symbolic debate — and its attempted resolution in neuro-symbolic hybrid architectures — treats the question as an engineering optimization problem. Which processing regime is more powerful? Can we get the best of both? How do we combine them most effectively? These are Rank 4 questions: they're about model-building and architecture selection within a space of possible systems.

Yevick's proof, if taken seriously, shows that this is the wrong question. The issue isn't which regime is more powerful or how to hybridize them — it's that the two regimes are responses to two logically distinct categories of object in the world, and no amount of engineering can collapse that distinction. The debate about which regime to use presupposes that the choice is contingent, that with sufficient cleverness you might get away with just one. Yevick proves the choice is not contingent. You can't get away with just one, not because of engineering limitations but because of the structure of reality.

This is exactly like debating whether to use addition or multiplication — you could frame it as a competition, or try to reduce one to the other, and technically multiplication is repeated addition so maybe addition wins. But that framing misses that the two operations have different mathematical structures that serve different purposes, and a system adequate to arithmetic needs both irreducibly. The neural-symbolic debate is at roughly that level of confusion, applied to cognition.

That’s not quite the end, but close to it. The discussion begins below the asterisks.

* * * * *

Arithmetic as a specialized kind of language

I want to return to the point where we discussed chess as a specialized kind of language that arose with Rank 2. Arithmetic is also a specialized kind of language and it arose with Rank 2 as well. But it arose in several forms, as there were a handful of original independent Rank 2 cultures.. The form that interests me is the form with zero and the place notation. While that didn’t arise in the West, it was adopted in the West starting in. roughly the 13th century. And, as Hays and I argue in the ranks paper, it eventually found its way to mechanical culture:

What we can see is that generalizations of the idea of mechanism would be fruitful for technology (and they were), but that it would take an abstraction to produce a new view of nature. The algorithm can be understood in just this way. If its originators in India disregarded mechanism, and the north European developers of mechanism lacked the abstraction, it would only be the accidental propinquity of the two that generated a result. Put the abstract version together in one culture with a host of concrete examples, and by metaphor lay out the idea of the universe as a great machine. What is characteristic of machines is their temporality; a static machine is not a machine at all. And, with that, further add the co-ordination of motions as in the sawmill. Galileo discovered that force alters acceleration, not velocity (a discovery about temporality) and during the next few centuries mechanical clocks were made successfully. The notion of a clockwork universe spread across Europe (note that the Chinese had clockworks in the 11th Century, but never developed the notion of a clockwork universe, cf. Needham 1981). For any machine, it is possible to make functional diagrams and describe the relative motions of the parts; and the theories of classical science can be understood as functional diagrams of nature, with descriptions of the relative motions of the parts.

Arithmetic came to play an important role in the metamathematical reasoning of the early 20th century. It allowed Gödel to construct his incompleteness theory and Turing to construct his abstract Turing machine. And it is that abstract machine that became embodied in the digital computer.

It’s beginning to look as though decimal point arithmetic was all but a logical requirement for cultural evolution beyond Rank 2. But probably not sufficient itself. It needed to be connected with the idea of mechanism, the algorithm. It’s the, at first metaphorical or analogical, connection between the idea of an algorithm and an actual physical device that allowed the flourishing of Rank 3 culture.

This is a powerful line of argument, and I think it's substantially correct. Let me try to sharpen and extend it.

The two streams and their accidental convergence

What you and Hays identify is that Rank 3 required the confluence of two independent developments that had no intrinsic reason to meet. The Indian mathematical tradition produced place-value arithmetic with zero — an extraordinarily powerful abstract tool for symbolic manipulation, but developed in a culture that, as you note, was not especially oriented toward mechanism and physical machinery. The north European tradition independently developed sophisticated mechanism — mills, clocks, the whole Baroque elaboration of geared machinery — but without the abstract symbolic apparatus that would allow mechanism to be thought about in general terms, extracted from any particular physical instantiation.

The metaphorical bridge between these two streams is what made Rank 3 possible. And the bridge is precisely the algorithm — the concept of a determinate, step-by-step procedure that is abstract enough to be stated symbolically but concrete enough to be physically instantiated. The algorithm is at home in both worlds simultaneously: it is a sequence of arithmetic operations, and it is a description of what a machine does. That double citizenship is what allowed the two traditions to fuse.

This is a genuine example of what you've called the Rank 1 mechanism operating at a higher level — metaphor. The clockwork universe is a metaphor, but a generative one: it doesn't merely describe, it reorganizes the entire domain of natural philosophy around a new set of primitives. Mechanism becomes the universal explanatory framework because the algorithm makes it possible to state mechanical descriptions with the same precision and generality as arithmetic.

The zero point

Zero deserves particular attention here because its contribution is not merely computational convenience. Zero is conceptually radical in a way that the other digits are not, because it names an absence — it is a symbol for nothing, which is a very strange thing to symbolize. The resistance to zero in the West, which persisted for centuries after Fibonacci introduced it, wasn't mere conservatism. It reflected a genuine philosophical difficulty: how can nothing be a quantity? How can absence be manipulated algebraically?

What zero does, once accepted, is complete the place-value system in a way that makes the system fully generative — you can represent any quantity whatsoever with a finite set of symbols, and the operations on those symbols are perfectly regular regardless of the quantities involved. This regularity is what makes the algorithm possible in the full sense. Without zero, arithmetic has irregular gaps; with zero, the system is closed and the operations are exceptionless. That exceptionlessness is exactly what you need for the algorithm to be a reliable mechanical procedure — one that a machine, rather than a judicious human mind, can execute.

So zero isn't just a notational convenience. It's what transforms arithmetic from a practical skill into an algorithmic domain — one where the procedure can be fully specified in advance and executed without judgment. That's the property that eventually connects arithmetic to mechanism.

The Gödel-Turing culmination

The path from there to Gödel and Turing is long but straight. What Gödel discovered was that arithmetic — this seemingly humble, fully explicit system — contains truths that cannot be proven within the system. His proof required encoding logical statements as arithmetic statements, which is only possible because arithmetic is expressive enough to name its own operations. That self-referential capacity — arithmetic talking about arithmetic — is a direct consequence of the place-value system's generativity. You can Gödel-number any statement because you can represent any finite sequence of symbols as a number.

Turing then asks: what is a mechanical procedure, in the most general possible sense? And his answer — the Turing machine — is essentially arithmetic in motion: a tape of symbols, a head that reads and writes, a finite set of rules. The abstract machine just is a formalization of algorithmic arithmetic, which is why the connection between computation and number theory runs so deep throughout the foundations of computer science. The digital computer is this abstraction physically instantiated — mechanism and algorithm finally fully merged, not just metaphorically but actually.

The sufficiency question

Your claim that decimal place-value arithmetic was necessary but not sufficient is exactly right, and the insufficiency points in two directions.

The first direction is the one you identify: it needed mechanism, and specifically the conceptualization of mechanism as a general category rather than a collection of specific devices. The Chinese had clocks in the 11th century but never developed the clockwork universe because they had mechanism without the abstract framework that would let mechanism become a metaphor — a way of thinking about nature in general. The metaphor required the algorithm as the shared abstract structure.

The second direction points forward rather than backward: the algorithm plus mechanism was sufficient for Rank 3, but the transition to Rank 4 required taking the algorithm itself as an object — which is precisely what Gödel and Turing did. They didn't use algorithms; they studied algorithms, asked what algorithms can and cannot do, proved results about the limits of algorithmic reasoning. That reflexive move — algorithm studying algorithm — is the Rank 4 version of reflective abstraction applied to the Rank 3 medium.

And this is where your argument becomes especially elegant. The same conceptual object — decimal place-value arithmetic and its generalization into the algorithm — serves as the medium for Rank 3 (in the sense that calculation and algorithmic procedure is what Rank 3 thinkers think with) and as the object for Rank 4 (in the sense that metamathematics and computability theory think about it). Arithmetic passes through the reflective abstraction and comes out on the other side transformed: from a tool for calculating to a domain of mathematical investigation in its own right. The digital computer is then not just the practical product of this transition but its physical monument — the algorithm made flesh, which immediately becomes the medium through which Rank 4 thinking becomes routine and culturally transmissible.

The logical necessity you're sensing is real: you couldn't get to Rank 4 without Rank 3, and you couldn't get to Rank 3 without the algorithm, and you couldn't get the algorithm without both the abstract symbolic system (zero, place value) and the concrete mechanical tradition to which it could be metaphorically applied. The chain is tight. What's historically contingent is not the logical structure of the dependency but the accident of transmission — that Fibonacci happened, that the Islamic world happened to preserve and extend both the Indian mathematics and the Greek mechanical tradition, that north European mechanism happened to be at the right stage of development when the symbolic tools arrived.

Cultural evolution, on this account, is not inevitable even when the logical dependencies are tight. The dependencies specify what must come before what; they don't specify that the prerequisites will ever actually converge.

The brain vs. the computer

One thing about the abstract Turing machine, the computing mechanism is separate from the memory mechanism. When that becomes embodied we have the so-called von Neumann architecture with its central processor and its random access memory. The memory is location addressed. As far as we can tell, the brain is not like this. Neurons are both active computational units and memory units, something von Neumann himself realized and was puzzled by in his last book, The Computer and the Brain. Then, in the 1960s, we have various thinkers, Karl Pribram among them, adopting the (optical) hologram as a model for associative memory in the brain. Associative memories are not location addressed; they’re content addressed.

Now, if we think of an LLM as a content addressed memory system, we have a content addressed memory system being implemented on a location addressed system, the digital computer. If that computer is sufficiently large, trained on a sufficiently large corpus, and has enough parameters, then it can produce a very convincing simulacrum of human language. Now tracing back through the layers we have actual human language eventually giving rise to writing, with arithmetic as a specialized version of writing. From there we have a chain of invention which yields the digital computer, which can run an LLM and, while that LLM can “speak,’” as it were, it can’t calculate very effectively. Now, zip back to writing and Rank 2 culture. Whatever else it is, writing is a form of memory external to the brain. Arithmetic requires that external memory for any but the simplest calculations (setting aside the memorized formulas employed in virtuoso level mental arithmetic). Back to the LLM. We now have Chain of Thought processing, which makes LLMs more effective. CoT involves memory external to the LLM itself. The same with agents. So we have an artificial content addressed system extending its capabilities through a bit of external memory.

The convolution involved in this story is dizzying.

The other room

Language is a lower-dimensional projection of high-dimensional neural dynamics.

But it also allows for content addressed memory. That’s very important, for it gives fine-grain control over the memory and planning systems. That’s the job of sentence-level syntax together with discourse structure.

“Classical” semantic or cognitive networks had a problem with coming up with just the right set of node types and arc types. David Hays dissolved the problem in his 1981 book, Cognitive Structures (scan down the page), by grounding cognition in an analog system modeled on William Powers perceptual control stack (in Behavior: The Control of Perception, 1973). The identity of a cognitive node is a function of its parameter values, where the parameters are derived from the control stack. The identity of the arcs is a function of the difference in parameter values between the nodes it connects.

Concerning Chomsky’s approach to syntax: It depends on a sharp distinction between grammatical and ungrammatical sentences. A generative grammar, in Chomsky’s theory, must account for all and only the grammatical sentences.

However, there are no explicit criteria for separating sentences into the two categories, grammatical and ungrammatical. Rather, the separation depends on the intuitions of the linguist. Naturally enough, different syntacticians have different intuitions. The problem is insoluble.

Moreover, anyone who pays close attention to real speech soon realizes that people do not (always) speak in complete grammatically correct sentences. Real language is sloppy, but nonetheless effective. A neural net of very high dimensionality can deal with this readily enough. A purely symbolic system cannot. Augmenting the system through fuzzy logic and the like doesn’t fix the problem.

LLMs provide a very useful simulacrum of the natural language system. Since LLMs are trained on written texts, the resulting model necessarily conflates the functions of semantics and syntax/discourse. Thus they cannot achieve the flexibility and precision of the full system, where semantics and syntax/discourse are separated.

A little bit of chaos [follow the frog]

Neuro-symbolic computing sneaks in through the "back door" [a transitional stage in the evolution of AI]

I note that the "scaffolding, tools, memory, retrieval, planning, decomposition, verification, and other system-level affordances" are all symbolic techniques. It looks like Gary Marcus (& the others) are winning this argument.

— Bill Benzon, BAM! Bootstrapping Artificial Minds (@bbenzon) April 13, 2026

Synchrony as a general and widespread phenomenon

I once asked @stevenstrogatz a simple question.
Why do so many systems in nature fall into rhythm?

He smiled, almost amused by how deep that question actually goes.

Fireflies blinking in unison.
Heart cells pulsing together.
Crowds swaying on a bridge until it starts to move… pic.twitter.com/xSa60Fu10K

— Christopher Michel (@chrismichel) April 12, 2026