Jay Forrester, giving a talk at a system dynamics conference I attended, asked the audience, "How many of you use models in your personal life?" Few if any, raised their hand. His response, "You all do; we all use mental models."

Excerpt from:
All models are wrong: reflections on becoming a systems scientist
by John D. Sterman, Jay Wright Forrester Prize Lecture, 2002
System Dynamics Review, Volume 18, Number 4 Winter 2002

All decisions are based on models . . . and all models are wrong

The concepts of system dynamics people find most difficult to grasp are these: All decisions are based on models, and all models are wrong. These statements are deeply counterintuitive. Few people actually believe them. Yet accepting them is central to effective systems thinking.

Most people are what philosophers call "naive realists": they believe what they see is, that some things are just plain True -- and that they know what they are. Instead, we stress that human perception and knowledge are limited, that we operate from the basis of mental models, that we can never place our mental models on a solid foundation of Truth because a model is a simplification, an abstraction, a selection, because our models are inevitably incomplete, incorrect -- wrong. Many systems thinkers illustrate this with the famous story of the ancient astronomer who taught that the world is supported on the shoulders of a giant. "But where does the giant stand?" asks a student. "On an immense turtle," the master replies. "But on what does the turtle stand" persists the student. "Another turtle." This goes on a while, until the exasperated master shouts out "It's turtles all the way down!"

Recognizing the limitations of our knowledge, the "inevitable a priori" assumptions at the root of everything we think we know, is deeply threatening (Meadows 1980). It's one thing to point out that someone else's opinions are 'just a model' -- it's quite something else to recognize the limitations of our own beliefs. And how are we to make decisions if all models are wrong? The concept that it's turtles all the way down, that there is no ultimate, absolute foundation for our beliefs, is so deeply counterintuitive, so threatening, that most people reject it as "obviously false" or become so dizzy with doubt that they run screaming as fast as they can to someone who claims to offer the Truth. Much of the misery people inflict on others arises from the arrogant belief that only we know the True Path, and the resulting intolerance and fear of any who profess beliefs different than ours. Fundamentalism, whether religious or secular, whether the unquestioning belief in an all-powerful deity, the all-powerful state or the all-powerful free market, breeds persecution, hatred and war.

To help people open up to a new perspective, a new model, and change deeply entrenched behaviors, we must often first help them see the limitations of their current beliefs. Doing so is difficult. But even when we succeed, it is only part of the challenge. Yes, we might solve an important problem if we can help people see through a new lens, improve their mental models, and thus make better decisions. But in a deeper sense, we fail our clients and students when all we do is facilitate the old organizational change recipe of "unfreeze, change, refreeze." We may only succeed in replacing one dogma with another, while strengthening people's belief that the scales have now fallen away from their eyes, that now they have the Truth. We must strive for more: helping people develop the critical thinking skills and confidence to continually challenge their own models, to uncover their own biases.

Yet we must recognize the inherent tension between being humble about the limitations of our knowledge on the one hand, and being able to argue for our views, respond to criticism, and make decisions on the other. Developing the capacity to see the world through multiple lenses and to respect differences cannot become an excuse for indecision, for a retreat to impotent scholasticism. We have to act. We must make the best decisions we can despite the inevitable limitations of our knowledge and models, then take personal responsibility for them. Mastering this tension is an exceptionally difficult discipline, but one essential for effective systems thinking and learning.

Also see the Primacy of the Whole.