Systems are mental constructs. They're defined by boundaries. The boundary of the system, the boundary of things we declare to be parts of the system, the boundaries of the concepts we use to construct, communicate, and reason about the system.
The words "system" and "boundary" can be misleading, like the word "process." As if nature contains conceptual abstractions.
Abstractions happen in cognition. Nowhere else.
But did you notice the choice, there, to place cognition outside of nature? Is that where it belongs? How would we know? Questioning and evaluating boundaries can press this question relentlessly.
I use "effectiveness" to try and trim back the brush. The concept of Nature is better at communicating, to you, the concept I am trying to communicate if I make that choice. It's more effective than saying "as if reality contains conceptual abstractions" or "as if the world contains conceptual abstractions." "Nature" and "the natural world" represent things that we investigate, and that we hold ourselves apart from. This sense of what is or isn't "nature" isn't perfectly correct, or provable, or something you can go confirm or deny in a dictionary. It's a boundary I have to draw as a practitioner, a choice in the architecture of my articulation.
What I think we're doing here is exploring general systems thinking and a surrounding conceptual vocabulary in the way that I use it to be effective in the world.
That intention is a boundary drawn around the ways I evaluate effectiveness. The fractility of this, boundaries about boundaries sprawling off into infinity, gives me vertigo sometimes. I think this kind of fractility is an indicator that I'm seeing something really basic, something deeply true, or at least useful.
Perceiving and perturbing the models we experience reality through, the boundaries that comprise them, is definitionally disorienting. Not just because of the fractility, but the universality. Grouping and classifying things is one of the basic ways we put ourselves on solid ground. Asking, "where do we draw this line and why?" (and the echo, how do we choose the "why?," and on, and on) calls everything around it into question, too. Suddenly, you're questioning everything! I've been making a habit of it for years, and it doesn't stop disorienting me. That wooziness has come to be one of my guides. If I haven't tried different boundaries around something until I'm woozy, I haven't really changed my perspective at all! And if I haven't challenged my perspective, I'm constrained to continue the way I'm already seeing something. If that's good enough, that's fine. If the way I'm seeing something is failing me, well, time to get woozy.
Wooziness is one path to noticing problems, and being able to actually do something about them. Serious, long-term mistakes live in our models more so than the decisions we make within those models. People who avoid woozy thinking too vigorously can become very, very stuck. They can be stuck on little things - small daily decisions in their work or personal life - and they can be stuck on big things, ideas about people and systems. This leaves them at the mercy of the stability of their environment, even assuming the things they were stuck on were any good in the first place. This leaves them in a disadvantaged situation, a dangerous situation.
Karl Weick wrote the most important book review I've ever read. Called "The Collapse of Sensemaking in Organizations: The Mann Gulch Disaster," it introduced me to many concepts I've used to understand what is going on around me for many years. It's long enough that I won't insist you read it right now. But we can add to Wikipedia's list of terms Weick introduced to the study of organizations (I'll save you a click: "loose coupling," "sensemaking," "mindfulness,") the notion of a "cosmology episode."
A cosmology episode occurs when people suddenly and deeply feel that the universe is no longer a rational, orderly system. What makes such an episode so shattering is that both the sense of what is occurring and the means to rebuild that sense collapse together.
Weick's own writing has plenty to say about how people handle cosmology episodes and how we might prepare for them. I recommend it. But. I have two reasons for bringing it up. Firstly, that wooziness I've been talking about is a cousin. Secondly, I think it takes something related to such an episode to really have a paradigm shift.
I take it as a fairly obvious premise that our world changing, and it is changing at an increasing pace. Being stuck in a mental paradigm that has been outpaced or superseded, (or is just a poor match for your context) is unpleasant and wasteful at least, and often cruel or dangerous. I want to be able to change paradigms. Unraveling boundaries until I'm woozy lets me notice mistakes and problems every day, but on a grander scale, it keeps me in paradigm-traversing shape.