Complex rules yields stupid results. Example: tax codes in most countries.
Must be a quote but I wasn't able to find a source for it.
When systems get too complex to simulate from first principles, we have to resort to inductive reasoning--observe the system and then create rules as we see a need.
Yes the resulting rule set is a mess, like our tax code. But the physical system that the U.S. federal tax code (for example) covers--the United States of America--is mind-bogglingly complex.
We have trouble computationally simulating more than a certain number of neurons... there are billions of neurons in each human brain, and there are hundreds of millions of human brains interacting in the U.S. This does not even get into other physical phenomena like surface water or mineral distribution.
The results are stupid because we are too stupid to understand and analyze the system we're trying to describe and manage.
Back when I was in academia I used to develop ABMs to represent the behaviour of complex systems with a simple set of rules of agent action and interaction.
The game of Life is the quintessential example of that.