This article is based on the theory of selforganizing systems, which I am not gonna refer here, but it should be understandable for everyone.
The question is: How can we create a system that is sensitive to its environment; sensitive to even the smallest differencies?
The solution is: Force the system into a decision between two or more ways, which lead to the same result finally. So the system will start to look out for any minor diffrences in its environment, to help it making a decision: it becomes very sensitive.