Requisite visual variety …
There are so many systems principles I wish someone had sat down and explained to me at the start of my career, but if I had to pick out one, it would probably be Ashby’s law of requisite variety. Stafford Beer called it the managerial equivalent of the law of gravity, and when you really get it, it is a bit of a Newtonian paradigm shift – suddenly a whole load of things make sense that didn’t make sense before.
Ashby’s law can be quite hard to get your head round if you’ve never heard of it before, but here’s a quick summary:
The world (as we perceive it) is made up of zillions of complex interacting systems. How complex is each system? Well, one way of defining that would be to count the number of states each system could be in, which is what Ashby calls the system’s variety. It’s a theoretical notion, because you can’t really count the number of states that anything but the most trivial of systems could be in, but that’s not the point. The point is that you can compare them. Two people have more variety than one person. A 16-bit computer processor has more variety than an 8-bit processor.
Now, Ashby’s law says that ‘only variety can destroy variety’. In other words, if you want to be able to exert control over something (i.e. reduce the number of states that it can be in), you need to be able to match that number of states yourself. You can only reliably manage something to the extent that you can match its complexity.
The problem is that, most of the time, you can’t!
Continues in source: Requisite visual variety … • Meaning Guide