By Jan Kwakkel

How can decision making on complex systems come to grips with irreducible, or deep, uncertainty? Such uncertainty has three sources:
- Intrinsic limits to predictability in complex systems.
- A variety of stakeholders with different perspectives on what the system is and what problem needs to be solved.
- Complex systems are generally subject to dynamic change, and can never be completely understood.
Deep uncertainty means that the various parties to a decision do not know or cannot agree on how the system works, how likely various possible future states of the world are, and how important the various outcomes of interest are.