Decision support systems can be used to manage systems. Managed systems are described by system specifications. System specification notations, such as UML, often separate in different diagrams the static specification and the dynamic specification of the system of interest. As a consequence, precious contextual information disappears, leading to misunderstandings during the interpretation of the specification. We claim that these problems result from a mechanistic view of reality. By taking a systemic view of reality, it is possible to develop a specification technique that integrates the static and dynamic aspects of the system and, hence, make the contextual information explicit. The benefit is the creation of more expressive system specifications that are less error prone when used for designing and managing systems.