“System—An integrated set of interoperable elements or entities, each with specified and bounded capabilities, configured in various combinations that enable specific behaviors to emerge for Command and Control (C2) by Users to achieve performance-based mission outcomes in a prescribed operating environment with a probability of success.
Source: Wasson, Charles S. (2016), System Engineering Analysis, Design, and Development: Concepts, Principles, and Practices, p. 2, New York: John Wiley & Sons, Inc.”
Since the beginning of modern day SE in the WWII timeframe, academia, industry, government, and professional organizations have attempted to establish definitions of a “system”. Constructively, the robustness of definitions created in these exercises is often inversely proportional the number of people participating. In general, you would expect more people vetting a definition to result in a more robust definition that is accepted across diverse disciplines, level of experience, and paradigms. However, in today’s world by the time professional organizations obtain worldwide vetting, “buy-in,” and approval of a definition, the resulting definition becomes so diluted that it loses its substantive meaning.
How does this happen? What starts out as a substantive discussion quickly evolves into grammatical and political “word-smithing games.” For example, group discussions exchange “happy” for “glad” to accommodate the wide range of experiences and sensitivities of professional disciplines, business domains, and factions within each discipline. Wasson, 2016, p. 3 provides an informative discussion of what occurs when teams of people attempt to focus on 1) content and 2) grammar simultaneously.
In general, technical definitions occur in two forms: 1) philosophy-based and 2) physics-based observations.
- Philosophy-based definitions are opinions formed by those of differing knowledge, skill, and experience levels, which vary from “I learned about the discipline yesterday and now I have a philosophy based on my (limited or no experience) opinion” to professionals with years of in-depth experience who actually know “how to” perform Systems Engineering and development (SE&D).
- Physics-based observational definitions are those based on observations of real-world, life cycle operations and characteristics of the entity or concept being defined. Such is the case for the Wasson definition above.
To illustrate this point, consider common definitions of a “system.” Philosophy-based definitions constrained by a minimalist words mindset define a “system” as follows: “a collection of people, processes, equipment and procedures, etc.” This checks the box for: 1) what a system consists of and 2) using the least number of words.
Many years ago a colleague gave everything the “So What?” test. If a system is “a collection of people, processes, equipment, procedures, etc. – so, what?” How does knowing this provide value in developing systems? It says nothing about the interrelationships among these elements or how they holistically produce a performance-based mission outcome.
The problem with philosophy-based definitions is they are typically opinions that fail to characterize a system’s unique characteristics and interactions of a system with its operating environment. Characteristics such as users, boundaries, mission, context, composition, capabilities, performance-based outcomes, context – when/where/how is can be used, probability of success, et al.
Now consider the definition of a “system” presented above (Wasson, 2016, p. 2). Technically, it characterizes what a system is based on physics-based observations of reality, not some opinion-based philosophy. Is the definition lengthy? Yes, but what phrases of the definition would you eliminate for the sake of reductionism and simplicity without impacting its robustness to characterize what a system really is and accomplishes? Observe how it provides: 1) substantive content, 2) context, and 3) passes the “so what” test in terms of value in developing systems.