[jdw64]

Is 'computation' really universal and fundamental? Turing machines, lambda calculus, algorithmic notations, they're all human-made formalisms. Are the halting problem and the limits of computability actually constraints that exist only within these human-made formal systems?

When we constrain a formalism to reduce complexity, it feels like necessity emerges from within those constraints. For example, when we say 'CRUD app,' we immediately think of a specific pattern. In the same way, once you adopt a 'form,' the constraints that come with that form progressively expand the state space. In that sense, it feels like both discovery and invention.

Famous mathematicians and scientists often distinguish between model and reality, yet we tend to mistake the model's shape for reality itself. People like John Wheeler and Stephen Wolfram argue that computation is a fundamental property of the universe. But can we really say that when we downcast reality to fit human cognition, losing information in the process, and then upcast it back, the information is fully restored? I always find this point difficult.

Landauer's principle says that abstract logical operations, information erasure, necessarily increase physical entropy. That shows there's a thermodynamic cost to physically implemented information processing. But I don't think that proves computation is fundamental.

Whether it's computation or geometry, they're all abstract formalisms created by humans. But when we actually measure things, they're subject to physical laws. Still, whether that makes them fundamental is a difficult question. I think these are just results of the process where humans name phenomena and constrain them. I don't think they're the cause.

You can define computation broadly enough, as 'a process where a state changes to another state according to rules,' to make almost everything look like computation. But being able to explain something with computation and claiming that computation is fundamental are different things, aren't they?

Meaning exists within the structures and constraints of human-made formalisms. We artificially lower cognitive complexity and translate things into human language. Whether that's fundamental, I'm not sure.

Maybe I'm a reductionist. Plenty of intellectually brilliant scholars make those claims, but people like me, with slower minds, end up thinking these kinds of stupid thoughts. I wish I could organize my own thoughts bette

[jojogeo]

Ahhh this is fantastic thank you; it _is_ hard to reconcile whether problems come with the original topic or whether they are introduced by the abstraction that we _need_ to make in order to quantify a thing/explain it to ourselves and others.

Regarding the downcast/upcast; I think it _can_ be possible to do this successfully;

> I have a glass, I throw it at a hard surface. What will happen? Well (duh) the glass will (most likely) break.

This hypothesis completely ignores nearly 100% of all relevant physics and the laws surrounding the problem; the arrangement of air molecules, the arrangement of the molecules in the glass, the physical forces governing me, it reduces the entire equation down to some really basic napkin physics.

But; does the outcome work? Has my interpretation of the universe and its physics actually predicted what will happen?

Probably a stupid example, but I think that a lossy picture of the universe can still yield a correct answer.

I can't physically run a simulation of the entire universe in my brain, as my brain is part of that same universe. Lossy representations/models are a necessity in the thinking-ham bound world in which we exist.

[jdw64]

You're right. But consider this: the geocentric model perfectly predicted planetary positions for centuries, and it was certainly useful. But could we say it was the essence of the universe? In the end, it's a useful model within limited cognition, but whether it's 'fundamental' is a separate question.

I think the key is that different phenomena require different approaches, and even if you interpret a single phenomenon through multiple mental models, none of them necessarily captures its essence. Ultimately, it's about which mental model is shared by a 'group'—not about what's fundamentally true.

We currently share the model of computation, but whether that makes it fundamental is a different story.

As a programmer, I'd put it this way: no matter how well an API describes the backend, the backend itself is not the API.

Here, the API is human knowledge, and the backend is the world

[amavect]

You sound like you believe in philosophical skepticism. Tell me: can a map ever properly describe the territory? When would a map properly describe the territory? (Can a theory ever properly describe reality? What does a theory need to properly describe reality?)

We know that universal Turing machines can emulate other Turing machines. Weirdos like Wolfram believe that a universal Turing machine can emulate reality. In a quick skim of this lecture series, the presenter doesn't talk about that, rather he just calls computation a scientific principal (universal and fundamental in the sense of physical laws, not fundamental in the sense of emulating reality on a computer).

[peter_m1]

We can still test the theory that computation describes physical reality with experiment (presumably it makes predictions). The scientific method still holds.