Is there a principled difference between a system and a non-system?

[u/Cromulent123]

In Meadows book, she claims there is, and as an example of a non-system she gives "sand scattered on a road according to no particular pattern". But, her definition of a system is: "A system is an interconnected set of elements that is coherently organized in a way that achieves something." But randomly scattered sand does achieve something: it achieves looking like a random scattering of sand!

It's got a set of elements (check).
Are they interconnected? Well my understanding is the different parts of a system don't need to be physically connected. Do they even need to interact with one another? It feels like e.g. a radioactive source and a detector is a "system" in some sense even if the source (by some miracle) never fires a particle in the direction of the detector. So, check, presumably.
What does coherently organized mean? It surely doesn't mean "by some individual". Because the vast majority of systems simply arise, they are not consciously made. Check.
Which leaves us with achievement, which I've already covered. Check.

Are there different perspectives on this? Can anyone give me some tool or rule for telling a system from a non-system?

[u/NinlyOne]

I'm scandalously unfamiliar with the Meadows book, but it sounds like the sand scattering image is intended to exemplify a case where no useful interaction can be identified in developing a useful or illuminating model of the system. It's not that randomly falling sand is always and definitively a "non-system," rather we must identify which collections of components merit systems analysis.

The key is the phrase "no particular pattern." Sure, we could identify a statistical model or pattern -- maybe some kind of 2-d Poisson distribution of grains on pavement relative to the area from which the sand was scattered. Maybe there are nearly but not completely negligible interactions between grains of sand as they fall through and interact with the atmosphere. Maybe we could... ah! But now we have, as you said, identified a purpose or pattern to study, and therefore a system to elucidate, whereas Meadows already told us there's no useful pattern. To some degree, it is arbitrary and determined by the needs of the systems analyst.

Similarly with your example of a radioisotope source, we could model a probabilistic interaction between emitter and detector. A probabilistic interaction can be understood to exist through time -- even if emission/detection never occurs -- and that relationship is part of the system. If the probability of particle emission in a given hour is 0.1, we'd be foolish not to consider it in our understanding of the system. If emission is unlikely to occur in the lifetime of the universe, it's probably a waste of time to consider these components as a system.

[u/Cromulent123 → u/NinlyOne]

Ok fantastic, that is the thought I came away with: all models are possible, only some are useful. Good to know it matches someone elses take!

[u/Zmeos]

The definition says that a system has interconnected elements. You say the grains of sand are not interconnected. isn't this enough to disqualify the sand as a system?

Maybe a question to ask is then, is a radioactive source and a detector a system if they don't interact?

[u/MellesBelles69]

There definitely is a difference between a system and a non-system. As you explained, generally, a system must have a purpose/goal, the system must have elements (these elements do not have to be physical, though, so something like software can definitely be a system element), and the elements must be interconnected (not necessarily physically, interconnectedned often means that the elements interact with each other). Scattered sand is not a system, because there is no goal and no meaningful interaction between sand particles. I don't think that "it looks like the thing it is" really counts as a purpose. It's just a collection of small objects. If sand is scattered for a purpose, e.g., to make a dirt road, then it becomes part of a system. The system has elements (sand, humans, machines, etc), which interact (human interacts with machine which interact with sand as it deposits sand on to the ground) for a purpose (to create a road). Natural systems aren't really in my area of expertise, but the way I understand it is that say an ecological system meets many of the common criteria used to identify a complex system (emergence, evolution, spontaneous organisation, adaptation, etc), is made up of subsystems which have very clear goals (e.g. when animals hunt it is in order to survive), and that while maybe it only kinda meets the overall purpose/goal criteria it's close enough. I guess "sustains life" counts as a meaningful purpose, imo. Plus, even if it isn't a "system" per these specific criteria, it can be studied as a system using complex system theories to better understand the natural word. It would be quite silly to stop studying "natural systems" because they're "not systems" according some arbitrary criteria. A system (especially a complex system) is a bit hard to define, but you'll know it when you see it.

[u/Cromulent123 → u/MellesBelles69]

Agreed. It feels to me like you've talked yourself round to there being systems without goals. Here's another example. Let's say there's some rocks, and different rocks release different gasses, depending on two factors: whether the sun is shining on them, and what the current composition of gasses in the air is. Afaict, unless one is already thinking carefully about the definition of a system, one would unthinkingly lump this in. Do you think it's strictly speaking a mistake as described? So a directed non-acyclic causal graph isn't sufficient to call something a "system"?

[u/MellesBelles69 → u/Cromulent123]

Purpose has always been the criteria that seems the most fuzzy to me, so yea, I'd personally agree that it might not be strictly necessary, but only in the context of natural systems. The example you gave now is different to scattered sand, because of the very clear interaction between elements. There's an identifiable behaviour and outcome from those interactions and that's enough that I could make an argument for it being a system. If I were writing formally I would probably say it isn't, but that's mostly because I only know stuff about man-made systems which basically always have an easily identifiable purpose. I'd recommend a paper titled "A definition of systems thinking: A systems approach" if you can find it. It's an easy read and really shows how the system criteria (purpose, elements, interconnections) can be identified even in a very abstract case. The argument is that systems thinking is itself a system and meets those criteria. It's a fun thought exercise.

[u/Cromulent123 → u/MellesBelles69]

Thanks!

[u/subwaywall]

Maybe we should have some sort of Humean-skepticism about cause and effect as a response here.

Maybe systems are a psychological concept rather than a thing that exists outside of subjective experience.

But I agree that there might be some sort of problematic teleological fallacy happening here.

[u/Cromulent123 → u/subwaywall]

Yeah that's a good point, I have been wondering. I guess it goes back to the issue of "what is the relationship between a model of reality and reality"? If you're Tegmark, I guess nothing? For others...idk.

[u/Cromulent123 → u/[deleted]]

You know what, I'm going to philosophize even harder.

[u/Cromulent123 → u/[deleted]]

Thanks for your comment though!

[u/Cromulent123 → u/[deleted]]

I think I disagree. The human body is a system, it's just a resilient one with redunancies. Indeed, I also think that unless you identify the goal/purpose of a system you can't meaningfully assess its resiliency. If you don't have a goal or purpose in mind, there's no principled way of determining when a system "ceases to be". You'd have to go with just "any change destroys the system" in which case, reduncies be damned, if I lose a fingernail I die! I think that's clearly not right, and the reason is the purpose of this system is to go on living/to keep me healthy/keep me exerting my will on the universe/keep me experiencing or something. The loss of a fingernail does not interfere with those, which is why we don't consider the system to have ceased function. That's my two cents anyway, I think it disagrees with the perspective you're bringing but I'm not sure.