15. One or more non-transitory computer-readable media having computer-executable instructions stored thereon that, when executed by at least one processor, cause the at least one processor to: receive first business logic expressed in one or more declarative languages, the first business logic including a first process description, the first process description describing a first process of a business process instance in terms of one or more flows; receive second business logic expressed in the one or more declarative languages, the second business logic including a second process description, the second process description describing a second process of the business process instance in terms of one or more rules, the second process being different from the first process; and execute the first business logic and the second business logic, wherein each of the one or more flows represents a control flow between business functions, wherein each of the one or more states represents a legal state transition for at least one business entity, and wherein each of the one or more rules represents a business rule or policy enforced on the at least one business entity in an externalized form.
15. One or more non-transitory computer-readable media having computer-executable instructions stored thereon that, when executed by at least one processor, cause the at least one processor to: receive first business logic expressed in one or more declarative languages, the first business logic including a first process description, the first process description describing a first process of a business process instance in terms of one or more flows; receive second business logic expressed in the one or more declarative languages, the second business logic including a second process description, the second process description describing a second process of the business process instance in terms of one or more rules, the second process being different from the first process; and execute the first business logic and the second business logic, wherein each of the one or more flows represents a control flow between business functions, wherein each of the one or more states represents a legal state transition for at least one business entity, and wherein each of the one or more rules represents a business rule or policy enforced on the at least one business entity in an externalized form. 16. The one or more non-transitory computer-readable media of claim 15 , wherein the first or second process includes one or more tasks, wherein at least one of the one or more tasks is selected from a library of tasks in which each task has a precondition and a postcondition, and wherein the desired precondition and postcondition are automatically determined prior to execution.