The Anatomy of a System (SNO)

Every system in SiD is built from three layers of abstraction: the System, the Network, and the Object. This hierarchy, called SNO, is the structural backbone of everything that follows. It sounds simple, and it is, but within that simplicity lies the power to see things most sustainability frameworks miss entirely.

A system in SiD is a set of objects and relations between individual components that operate together, exchanging information, energy, materials, value, and other resources. Systems are a mental and analytical model. They are not real in the way a table is real, but they form a powerful framework for understanding. A city can be a system. A company, a government, a pond, a household, our entire civilization. Systems are defined and separated by their boundary: where the system ends and the rest of the world begins.

The three levels work as follows:

The Object Level is the collection of physical elements in the system. In a city, objects include everything you can point to and name: buildings, roads, pipes, vehicles, people, animals, trees, money, energy. If you took a photograph and pointed to everything visible, those are objects. This is where you encounter the topics most commonly associated with sustainability: energy use, materials, ecosystems, climate impact, economic output. Objects have physical properties: size, mass, composition, location. Combined, these describe the object fully. The Object level uses the ELSI categorization system, which we cover in the next unit.

The Network Level captures everything that flows between objects. It is the movement of people and goods, the flow of information, resource exchanges, laws, regulation, trade, economic transactions, cultural connections, power dynamics. Unlike objects, network connections are intangible and dynamic. Some are easy to grasp (transport routes, communication systems, supply chains). Others are harder to see (cultural influence, informal power structures, trust networks). The network is where the "magic" of system dynamics lives. This is where leverage points hide, where small interventions can produce outsized effects, and where unintended consequences originate. Simply put: everything you cannot see but is there is likely a relationship, and part of the network.

The System Level is where the underlying levels come together and are evaluated as a whole. It determines the edges of the system and assesses performance holistically. The system level is informed from both bottom-up (object data aggregated through network patterns) and top-down (system goals driving what we look for). It is at the system level that sustainability can be evaluated, through its three core indicators: Resilience, Autonomy, and Harmony. The system level is the most abstract of the three layers. As a consequence, it can be both the most insightful and the most confusing. But it is where the most impact lies, where our long-term goals live, and where the highest-leverage actions originate.

Here is the critical insight: we set goals on the system level, and operate on the object level to make them happen. The network level is the bridge between the two. The network parameters connect abstract goals to concrete actions, and reveal hidden opportunities to use system dynamics to our advantage.

A few definitions worth keeping straight:

• Indicators are measures that "indicate" a certain performance aspect. They combine properties into a formula.
• Properties are directly measurable aspects of objects: size, mass, temperature.
• Parameters are network-level measures that are not always directly measurable but can be derived from the relationships between objects.

The SNO Hierarchy diagram provides the complete overview: the ELSI categories for objects, the network parameters (CRAFTDCCV for resilience, SSCNE for autonomy, PEAIE for harmony), and the system indicators (Resilience, Autonomy, Harmony leading to Sustainability). Keep it close. You will use it throughout the rest of this course.