The Logical Thinking Process — a guide
A plain-language introduction to the Logical Thinking Process (LTP), the Theory-of-Constraints method that Reason Commons builds on.
The Logical Thinking Process — a guide
The Logical Thinking Process (LTP) is the method underneath Reason Commons. It comes from the Theory of Constraints, developed by Eliyahu Goldratt and later codified for general problem-solving by H. William Dettmer. It is the most thorough, best-realised way we know of doing what this project is about: laying out a goal, the things blocking it, and the change that gets past them — as connected trees rather than prose.
You do not need any of this vocabulary to use Reason Commons. The site keeps LTP's rigour and hides its jargon. This page is for people who want to know what is under the hood, or who arrived searching for it.
The core idea
Most hard problems in organisations and movements are not puzzles to be solved once; they are systems with a small number of binding constraints. If you can find the constraint and the assumption that holds it in place, a modest change in the right spot moves the whole system. LTP is a disciplined way to find that spot and agree on it.
It works through a sequence of trees, each answering one question any real change has to answer:
| Tree | Question it answers |
|---|---|
| Goal Tree | What are the enduring conditions that must hold for us to reach the goal? |
| Current Reality Tree | Why are we not there now — what chain of cause and effect produces the symptoms we see? |
| Evaporating Cloud | What underlying conflict keeps us stuck, and which assumption under it is false? |
| Future Reality Tree | If we make this change, does it actually produce the outcome — and what new problems does it create? |
| Prerequisite Tree | What has to be in place, and in what order, before the change can happen? |
| Transition Tree | What concrete actions, with observable effects, carry it out? |
The first trees are the tree of change — where the goal is, what is in the way, why. The last are the tree of action — what to do about it, in order. Every leaf stays connected to the claim or goal above it, so you can always see how a small step relates to the whole.
A worked example
The pages in this section are a complete LTP analysis of one real organisation — the Second Renaissance movement — reconciled into a single evidence-backed model:
- Project model — the five source documents rebuilt as one causal model
- Goal Tree · Current Reality Tree · Evaporating Cloud
- Future Reality Tree · Prerequisite Tree · Transition Tree
- Recommended next action · Assumptions and open questions · Coverage and evidence
Read more
The reading list has the three books worth starting with — a short executive summary, the definitive reference, and the business novel that started it all.
