The ISSS symbol is a gestalt figure. If you stare at it for a while, you may notice that your perspective can/will change. This change or gestalt demonstrates the kind of system we talk about. Once the systemness is grasped through direct experience, then you become the expert.
Notice how from one perspective it is the parts that dominate. One could analyze these parts and describe the parts on the left, or the parts on the right, or the parts inbetween or even the background. Notice how this is done in a linear fashion, that is, one can start at some place and move around to other places.
Notice too, from another perspective the whole dominates. Linear doesn't apply anymore. It is this second perspective that is called herein “systemness”.
Now consider the question: How do I read the Primer? Answer: While you must read linearly, perhaps starting with topics that interest you, you can only understand it all at once.
In order to “grok” the Primer, one has to be able to perspectualize it simultaneously, as a whole.
Explaining a system is not very productive if the system being explained is something brand new to the reader. And if the system involves many elements, as all systems do, grasping the essence of the system may not happen by merely reading about it. Our knowledge does not go beyond our experience, simple as that. Therefore we must use metaphor, analogy, and draw from experience, to understand systems.
The kind of systems we are talking about here are not ordinary “systems” that are an assemblage of parts or actions. A significant aspect of a system is the emergence of a new property - a property not seen in the parts alone. The wetness of water, for example, cannot be found by an analysis of the gases it is composed of. Nor can the meaning of these words be found by an analysis of the black or white parts.
And while it seem at first that the task of understanding complex systems is almost insurmountable or at the least very difficult, actually it becomes, once grasped, simple and in most cases obvious. Eventually the meaning and order in the systems will emerge in our minds, as we wrap ourselves around the ideas, then absorb them, and finally comprehend the meaning of 'system.'