Classificationwhat exists?
Interactionwhat depends on what?
Evolutionhow has it changed?
Causalitywhy did it happen?
Predictionwhat comes next?
The fifth pillar
The periodic table wasn't revolutionary only for organizing known elements — its structure predicted elements not yet discovered. Imagine Pieriodic one day finding: "Ports that adopted strategies A, B, and C often went on to adopt D within five years." That's the beginning of a theory of port decarbonization. (Prediction is the long-term ambition, not a claim about the product today — the first step is a reliable history of what happened, where, and why.)
What exists — and what's possible
A periodic table describes what exists. A phase space describes what is possible — all the states a system could reach — and a trajectory moves through it over time. CAAP is one trajectory. Another port may follow a different one. Green shipping corridors create trajectories beyond a single port. Future solutions open trajectories not possible today.