ABSTRACT
A system is a collection of separate parts that, because they are linked to and affect one another, are interdependent. This interdependence means that understanding how the system works requires understanding not only how each of the parts works individually, but also how they interact with each other. A mechanical clock offers a nice example. Each gear and spring is a separate part, but each of these separate parts interacts with other parts to make the clock run. To understand how the clock runs, it would be useless to study each gear and spring separately. The parts must be studied together, with a view toward understanding how each part interacts with and affects the other parts, and how in combination they produce the outcome that we call “telling time.”
