"The Five Attributes of a Complex System":

1. "Frequently, complexity takes the form of a hierarchy, whereby a complex system is composed of interrelated subsystems that have in turn their own subsystem, and so on, until some lowest level of elementary components is reached.
2. The choice of what components in a system are primitive is relatively arbritary and is largely up to the discretion of the observer of the system.
3. Intracomponent linkages are generally stronger than intercomponent linkages. This fact has the effect of separating the high-frequency dynamics of the components - involving the internal structure of the components - from the low-frequency dynamics - involving interaction among components.
4. Hierarchy systems are usually composed of only a few different kinds of subsystems in various combinations and arrangements.
5. A complex system that works is invariably found to have evolved from a simple system that worked ...A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over, beginning with a working simple system.

1. the use of the object model helps us to exploit the expressive power of all object-based and object-oriented programming languages.
2. the use of the object model encourages the reuse not only of software of entire designs.
3. the use of the object model produces systems that are built upon stable intermediate froms, and thus are more resilient to change.
4. the object model reduces the risk of developing complex systems, primarily because intergration is spread out across the life cycle rather than occurring as one big bang event.
5. the object model appeals to the working of human cognition."