Seen Again

Notes on thinking and looking.

The Ladder

A working model with five levels, and one judgment that sits above them. It is the map for the essays on this site. It is not a law, and the section at the end says where it fails.

Five levels of thinking rise like steps; choosing the level, and why, sits above them Five steps rise from left to right, labeled tangible, abstract, principle, system, loop. Above them, in the accent color, a note says that choosing the level, and why, sits above the ladder. 1 2 3 4 5 Tangible Abstract Principle System Loop Above the ladder: level, and why

1. Tangible

Attention on one specific thing or event, the kind you can point at. A cup, a queue, a clock, one student's exam paper. This level is high-resolution, not primitive. It is the level where debugging lives, where teaching one student happens, where craft lives, and where a diagnosis begins. Read The Cup on the Table.

2. Abstract

Pulling out what several tangible cases share, and deciding which differences do not matter for your purpose. Every category is a decision about what to ignore, so abstraction is always a lossy compression. Read Ten Cups, One Word.

3. Principle

A general rule or value that tells you what to do or expect in cases you have not met. An abstraction given authority over action. Principles have scope, they have exceptions, and two good principles can pull in opposite directions. Read Rules That Travel.

4. System

Explaining behavior by structure: parts, relationships, stocks, flows, constraints, boundaries. The same parts arranged differently behave differently, which is why blame moves from persons to arrangements. Read The Queue Is Not the People.

5. Loop

Adding time to a system view. Outputs return as inputs. Reinforcing loops amplify, balancing loops seek a target, and a delay turns a stable arrangement into an oscillation. Read The Shower Tap and the Thermostat.

Above the ladder

The judgment about which level a situation needs and why. It has four parts: frame selection, purpose, learning how you learn, and return to the tangible. Read Which Lens, and When.

Where this model is weak

This section is deliberately plain, because a model that only lists its strengths is marketing, not thinking.

The levels are lenses, not rungs

Each level makes certain things visible and hides others. Calling them steps suggests a fixed order and a single correct altitude, and that is not how thinking works. A good analyst moves up and down on purpose, and so does a good teacher. The ladder is a set of positions to move between, not a staircase with a top.

Higher is not better

A system explanation of a queue is not worth more than a careful look at the person who keeps changing lanes. The point of moving up a level is to change what you can do, not to gain status. Staying low and concrete is often the right answer, and the phrase "too concrete" is usually a cover for not looking.

The order is a teaching convenience

Tangible, abstract, principle, system, loop is a sequence that makes sense for teaching. It is not a sequence that situations arrive in. Real thinking jumps. A student asks a system question in the middle of an abstract question, and the question may be more interesting for it.

Real thinking jumps between levels

Nobody argues entirely at one level. A nurse looks at a patient, recalls a pattern, checks a guideline, notices the ward is short staffed, and adjusts. The model is a description of movements we make anyway, and it is most useful as a way to notice which movement we are making.

The levels are not drawn from one source

The five levels are the author's working model. They borrow from many traditions, including hierarchical models of learning and systems thinking, but they are not a faithful summary of any one of them, and they are not established science. Treat them as a workshop tool that is useful enough to keep refining, and keep checking them against cases that do not fit.

Next: the Field Guide, which turns the model into six questions you can ask yourself.