Lever Point

Lever points (also named 'Leverage Points') in a [[Complex_Adaptive_System|complex adaptive system]] are according to John H. Holland points at which a small effort can produce a desired, directed effect. They are places within a complex adaptive system where a little change makes a big difference and a small shift a big change. At these critical transition points the behavior of a complex system changes fundamentally. They are similar to Gell-Mann's [[Frozen_Accident|frozen accidents]]. Lever points identify places to intervene in a system.

John H. Holland writes about them (see [http://www.capatcolumbia.com/CSFB%20TLF/2000/holland_sidecolumn.pdf here])
: "Almost every complex adaptive system that we know of has lever points. These are great things if you can find them. A lever point allows you to make big, directed changes for a relatively small effort. A vaccine is a good example of a lever point. An immune system is terribly complex. But we do know that for some diseases, we can make a small injection and train the immune system to resist a disease for the rest of its existence — much longer than the life span of any blood cell in your body."

see also [[Butterfly_Effect|butterfly effect]], [[Path_Dependence|path dependence]], [[Frozen_Accident|frozen accident]]

[[Category:Basic Principles]]

If there are only a few lever points, where a small effort can produce a large effect, then the majority of points and events are ordinary points, where a small effort has only a small or even vanishing effect. These are points where a little change makes only a little difference.


== Links ==

* The Scientist article from John H. Holland [http://www.the-scientist.com/article/display/54988/ Biology's Gift to a Complex World]

* Paper from Donella Meadows about [http://www.sustainer.org/pubs/Leverage_Points.pdf Leverage Points]