Fabric of Reality Book Club

Wait, do you view the pruning as separate from the mere competition of ideas…?

Yes. When I say ‘pruning’, I’m referring to a specific mechanism of a meta algorithm in the mind. For more details, see my book A Window on Intelligence, I think chapter 5. There is no such meta algorithm in biological evolution.

One of my previous comments notwithstanding, don’t be shy to mark ideas as criticisms whenever you point out a shortcoming. In the context of Alzheimer’s, this sounds like a criticism.

I still see epistemology as distinct, and I'll try to make my case for it. Epistemology explains how humans create explanatory knowledge — unlike biological evolution, which also produces knowledge, but not explanations. Explanatory knowledge is special because it allows us to understand the world. Deutsch even suggests that this kind of knowledge tends toward convergence — a unified theory of everything — implying a deep connection between reality and its capacity to be explained.

Economics, on the other hand, isn’t distinct in the same way. It deals with trade-offs and scarcity — principles already fundamental to biology. Life itself is about managing limited resources and the trade-offs that come with them. Evolution, in turn, discovered increasingly effective strategies for doing so — including cooperation, exchange, and other relationships between and across lifeforms that facilitate these trades.

In that same vein, why couldn't we class biology (evolution) under epistemology?

Yes, but that inhirent in biology (evolution) right? I see it as part of the evolutionary strand for this reason.

I currently see Constructor Theory as a meta-theory. A different mode of explanation. But it raises an interesting question: does CT actually qualify as a deeper theory than the four strands? Even if we were to express all four strands in constructor-theoretic terms, that alone wouldn’t make it explain more or have greater reach. So when would it truly deserve to be considered a strand/theory of everything?

Economics as a fundamental study of trade-offs.

My point is rather that it's not so clean a line between explicit and inexplicit. You're a doctor, so imagine the steps being something like:

1. Extensive description of patient's symptoms, test results, conclusion, etc, in English.
2. Same as above but mostly made out of quick notes by attending doctors and nurses.
3. Only a collection of test names and test results. Test results accompanied by Chinese.
4. Just a collection of numbers coming out of tests, without saying which test.

Arguably all the information is always there, and can be read off, but with increasing difficulty, requiring you to learn another language, or do a series of deductions.

Haha not a programmer so understood maybe half of it, but I think I see what you mean. There'll always be inexplicit parts to every explanation. My concept of explanations is that there must be at least some explicit part for it to be called an explanation. That's why genes aren't explanations.

Yeah that's definitely a possible medical condition, e.g. in psychosis or after having ECT. Don't think it's the best explanation for Alzheimer's though, where the loss of brain volume is so apparent.

Wait, do you view the pruning as separate from the mere competition of ideas, or simply its hardware consequences? In Darwinian evolution, competition and pruning are the same phenomena. Would expect the same for the mind.

The pruning mechanism is part of it, but there’s more. Again, there’s also competition between ideas and even predatory behavior that can result in the elimination of ideas. All such phenomena taken together constitute natural selection in the mind.

Not a doctor. But it's not hard for me to imagine untainted memory but a script with an error such that it can't manage to look up the information.

Let's fuck with your intuitions a little bit:

Say "stop" when it's no longer an explanation:

• Didactic chapter in plain English with examples and edge cases, distilled into a concise technical note with formal definitions, invariants, and pseudocode.

• Literate program interleaving prose and code, or a heavily commented Python implementation with docstrings and tests.

• The same code stripped of comments/tests and then minified or obfuscated (e.g., Python one‑liner, obfuscated C), up through esolangs and formalisms (Brainfuck, untyped lambda calculus with Church numerals, SKI combinators).

• Operational specifications with minimal labels (Turing machine tables), then hand‑written assembly without labels and self‑modifying tricks, down to raw machine code bytes/hex and binary blobs with unknown ISA or entry point.

• The same bits recast as DNA base mapping with unknown block codec, unknown compression, encrypted archives indistinguishable from noise, arbitrary bitstrings for unspecified UTMs, or physical media (flux/RF) without modulation specs.

Hmm never thought of that, interesting! I think since the disease involves continuous loss of brain volume, harsware decay seems like the best explanation.

In general I think it makes sense to speak of diseases in neurology (e.g. Alzheimer's, Parkinsons, stroke) as bad hardware and psychiatric disease as bad software. But it could very well be that some of those diagnoses are miscategorised.

That pruning mechanism is what constitutes natural selection in the mind.

Makes sense, thanks Dennis. Constant pruning is the explanation that retains scarcity and competition, while making the brain seem to have much more memory than it does.

Since you’re a doctor, Erik, let me ask: is there a possibility Alzheimer’s could be explained in terms of bad software? Correct me if I’m wrong, but it seems like the prevailing view is limited to bad hardware.

By the way, how is this a criticism? #2200 makes no mention of memory.

I have speculated in the past that ideas compete for attention, but they also compete for any kind of memory, be it something like RAM or hard-disk memory. The RAM-like memory in the brain is presumably closely related to working memory, if not the same.

The reason most people don’t run out memory (of both kinds) isn’t that memory isn’t scarce but that there’s a pruning mechanism in the mind. And again, there’s competition. That competition can involve predatory ideas which disassemble the source code of other ideas and use it for themselves because that’s cheaper than to construct source code from scratch.

Of course, memory isn't infinite. But most people don't seem to run out of it in their lifetimes. Is it more accurate to say that ideas compete for working memory, which is scarcer?

Everyone has scarce memory. Everyone’s brain has limited storage space.

Most people (except in Alzheimer's, etc.) don't run out of memory in the brain. If there's no scarcity for the space of ideas, why do they have to compete?