Turtles all the way down

There is an Indian story — at least I heard it as an Indian story — about an Englishman who, having been told that the world rested on a platform which rested on the back of an elephant which rested in turn on the back of a turtle, asked (perhaps he was an ethnographer; it is the way they behave), what did the turtle rest on? Another turtle. And that turtle? ‘Ah, Sahib, after that it is turtles all the way down.’ – Geertz, C. (1973). The Interpretation of Cultures.

Turtles all the way down is an expression of the problem of infinite regress, which alludes to the mythological idea that the earth rests on the back of a turtle or elephant.

It is a polysemic expression used in the humanities (e.g. Geertz) as well as the sciences (e.g. Kay).

An implementation of this expression forms the central pattern of the book I am working on: “central” in the sense that it is the center of centers of “communicating components that work together to provide a comprehensive set of capabilities”.

Here, I borrow from Christopher Alexander in Richard Gabriel. A “successful” center, Gabriel writes, “is surrounded by a boundary which is itself made up of centers”.

If the pattern of the book I am working on is successful, it will radiate polysemic, plurivocal contexts without being superficial and, like Geertz’s implementation of the turtle expression, it will include answers that others have given. Rather than reporting a conclusion, it should sustain the ongoing discourse of human experience, presenting constructions as part of a developing system of scientific analysis.

I can relate what happened the moment this pattern occured to me, bringing immediate perspicuity to topics I had struggled to interrelate cogently – such as how I would relate the chapter on esoteric programming languages (esolangs).

A typical first challenge in creating an esolang is to write a quine, which is a program that produces as its output its own source code. Quines, like “turtles all the way down”, can be extended to multiple levels of recursion. Esolang quines are now directly related to the book’s central pattern, or “center of centers” (cf. Gabriel).

Other examples of extendible recursion in programming include Lisp implementations that are self-hosting, like Lisp compilers written in the Lisp language, enabling them to self-program. They become stand-alone programs because they can do their own compiling.

Alan Kay’s 2004 comment about Lisp illustrates the significance of why it is worth making the effort to discover patterns that are “successful” centers:
that was the big revelation to me when I … finally understood that the half page of code on the bottom of page 13 of the Lisp 1.5 manual was Lisp in itself. These were “Maxwell’s Equations of Software!” This is the whole world of programming in a few lines that I can put my hand over.

Centers of centers are higher-level patterns that can explain and better illuminate lower-level patterns.

Ironically, the pattern came to me when I thought I was wasting my time reading about how compiler programs work – a topic I find compelling even while I doubt my ability to understand.

even his friends are unable to divine where he is or whither he is going, that they will sometimes ask themselves: ‘what? is he going at all? does he still have- a path?’ – Nietzsche

Yet it turns out that multiple accounts by people learning about compilers also vocalized doubts, whether their own or expressed by those around them, that they were wasting time in the attempt, as this knowledge is not directly financially remunerable. So, trying to learn about compiling is also representative of an activity that does not work in service of Optimization – capitalized because it could be said to be a pattern of our age.

“Wasting time” to consider how GNU Emacs Lisp can do its own compiling or how Smalltalk is “objects all the way down” can be compared with Nietzschean “slow reading”, which

demands of its votaries one thing above all: to go aside, to take time, to become still, to become slow — it is a goldsmith’s art and connoisseurship of the word which has nothing but delicate, cautious work to do and achieves nothing if it does not achieve it lento.

With Nietzsche I conclude that ceding to this “subterranean” mining and undermining of slowing down ultimately comes with the air of an “ancient faith”.

To commence tunelling into foundations or into the construct or pattern of “turtles all the way down” is perhaps to find Socrates’ ancient daemon or Muse – which comes with the warning that one should know some truth about “the matters of which he is to speak”, “if a speech is to be good”… And so, the challenge continues.

Bonus links and quotes:

1980 – Alan Kay creates Smalltalk and invents the term “object oriented.” When asked what that means he replies, “Smalltalk programs are just objects.” When asked what objects are made of he replies, “objects.” When asked again he says “look, it’s all objects all the way down. Until you reach turtles.” – James Iry, A Brief, Incomplete, and Mostly Wrong History of Programming Languages via Language Log

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