James P Houghton

# What is a system?

08 Mar 2012

If this blog is going to be about learning to see systems, how will we know when we’re succeeding? What does a system look like? How will we recognize one when we see it?

The more I pay attention, the more I realize that while systems are everywhere, not everything is a system. We probably wouldn’t call a plank of wood, or bar of soap systems, we’d probably just call them ‘Objects’. There are some things that we’re pretty sure are systems: a rocket-ship or a smartphone, to name a few. A rocket-ship is more than just an object; in fact, a rocket is made of millions of objects, and without each one, it probably wouldn’t work. That sounds like a good clue to it’s system-ness, and certainly sets it apart from the bar of soap. Let’s try using it to write a definition:

System: A set of objects.

But does having lots of parts make it a system? What if we had lots of planks of wood, or lots of bars of soap? We might have a mess, but I don’t think we would have a system. A rocket has more than just a bunch of parts, but what else? In the rocket, all of the parts interact with one another, and have relationships with one another. That sets the rocket apart from a soap collection, so let’s add it to our definition:

System: A set of objects that interact with one other.

Now, of course, a set of rocket parts could have relationships with one another that aren’t useful, ie, they could be in a pile. In that case there are a lot of relationships present, primarily “being tangled together in a big mess”. But a pile of parts isn’t really a system. There must be something about system interactions that sets them apart from other interactions. In the rocket, those interactions allow the rocket to fly, when none of the parts themselves could. The rocket as a system provides a function that the individual objects can’t give us. That sounds good:

System: A set of objects that interact with each other to create a function not present in the individual objects.

When we take a pile of rocket parts, and we build a rocket out of them, we add structure to them. The functionality of the rocket emerges from that structure. If the structure changes, then the behavior of the system will also change.

So when we look for systems, we can look for multiple interacting parts, and a system behavior which depends on the way those parts interact. Our definition suggests that if we find those, we’ll know we’ve found a system.

Unfortunately, the definition doesn’t help us do much more than point in the right direction. To understand the system, or even see what the boundaries are for the system, we’ll need more insight. I’m looking forward to exploring that as we go along.