We know that all models are wrong. It's obvious. We say so all the time, nod at Box, and move on. We are less clear about what "wrong" means, especially in complex domains. Any model must exclude something, and what we leave out does not disappear. It keeps interacting with the rest of the system in ways we cannot predict, as the system and its environment develop over time.

This is especially important in the transition from thinking in systems to designing them. When exploring a domain to understand it, we bring in as many perspectives and information as possible – even normative. It is a contextual activity, being provisional, open, and even speculative. Building the system, on the other hand, is mechanistic, requiring commitment, reduction, and exclusion. This is not just a different approach. It is epistemologically another thing.

Thinking in systems is not the same as designing them. Conflating these destroys both what we seek to understand and what we wish to create.