Your Plans Fail at the Boundary.
Bertalanffy, Boulding, and the structural flaw you can't engineer away.
When I lived in Germany, I decided to install better lighting in the washroom. A simple job, the kind of thing you start on a Saturday morning with coffee and a boatload of misplaced confidence.
The house had no wire routing channels inside the walls. The wires were plastered directly into them, invisible, with no indication of where they ran. I found out about this the way you find out about most structural surprises in old German houses: by drilling straight through one and seeing fireworks come out the end of the drill.
What followed was not an afternoon. It was six days of peeling plaster, rerouting wires, replastering, and repainting an entire washroom to fix a problem I created while trying to solve a completely different one.
I went in looking for better light. I came out with a complete understanding of why you should never assume you know what’s inside a German wall.
Ludwig von Bertalanffy would have recognized this immediately. Not the drilling, though he might have appreciated the symbolism. The actual problem was that I had treated the existing finishing of the washroom as a closed system. I had a clear input (drill here and there, mount fixture) and a clear output (better lighting).
What I had not accounted for was the boundary: what was actually happening behind the plaster, invisible to me and , and what would happen the moment I interrupted it.
This is what Bertalanffy spent much of the 1940s and 50s formalizing: most systems in real life are open. They take things in from their surroundings, transform them, and send outputs back out. Any model that treats them as sealed containers will eventually meet the wires inside the wall.
Bertalanffy was a biologist, which gave him an unusual vantage point. Biology is full of systems that appear self-contained but are constantly exchanging matter, energy, and information with whatever surrounds them.
His General Systems Theory was a long argument that you cannot understand something by isolating it from its context.
Then in 1956 Kenneth Boulding picked up this thread and made it legible across disciplines. In “General Systems Theory: The Skeleton of Science,” he argued that the real problem was the habitual practice of drawing walls around specific domains and ignoring what crossed those walls.
Each field had its own models, its own preferred way of being wrong, and very little interest in looking over the fence.
Boulding’s hierarchy of system complexity ran from mechanical frameworks (clocks, thermostats) through open systems (cells, organisms) up to social and symbolic systems.
Each level of complexity requires a fundamentally different mode of analysis, and using a lower-level tool on a higher-level system produces very confident nonsense at scale.
A closed system operates on fixed inputs. It doesn’t receive new information from outside at will, doesn’t adjust to changes in surrounding conditions. A thermostat is approximately closed, at least until you have a voltage spike coming from the power line. A business plan presented in January for the full calendar year is, in practice, treated as closed.
An open system is different. A cell exchanges material continuously across its membrane. An organism regulates temperature by sensing and responding to what’s outside it.
A plan built as an open system absorbs feedback, updates its assumptions, and changes course without requiring a full crisis to justify the change.
Bertalanffy introduced the concept of equifinality to describe one key property of open systems: the ability to reach the same end state through different starting points and different paths, because the system is continuously adjusting based on what comes in from outside.
Most planning treats equifinality as a flaw to be engineered out. The instinct is toward a single path and a fixed sequence, where any deviation reads as failure rather than adaptation. What Bertalanffy was pointing at is that the ability to deviate and still arrive is not a weakness in the design. It is the design.
What to watch for
Plans that function as closed systems share a few identifiable characteristics.
The timeline has no slack built in
The assumptions are stated once and never revisited
The success metrics are defined entirely by internal outputs, with no mechanism for incorporating anything from outside the plan’s own logic.
When you see a plan built this way, the question to ask is not whether it is internally consistent. It probably is. The question is whether the boundary has been designed to receive anything from outside, and whether there is any way to respond when it does.
One move
Before you finalize a plan, draw its boundary explicitly. Put the plan inside a box on paper, then list what enters from the surrounding and what leaves. What are the inputs, where do they come from, what outputs does the plan produce, and where do they go? Who or what is on the other side of each exchange?
You don’t need to predict everything that will come in. You just need to build a system capable of receiving it without the whole wall coming down.
Happy Building,
— R.