Editing Complexity (section)

== Sources and factors ==
There are generally rules which can be invoked to explain the origin of complexity in a given system.

The source of disorganized complexity is the large number of parts in the system of interest, and the lack of correlation between elements in the system.

In the case of [[Self-organization|self-organizing]] [[living systems]], usefully organized complexity comes from beneficially mutated organisms being selected to survive by their environment for their differential [[Reproduction|reproductive ability]] or at least success over inanimate [[matter]] or less organized complex organisms. See e.g. [[Robert Ulanowicz]]'s treatment of [[Ecosystem|ecosystems]].<ref>Ulanowicz, Robert, "Ecology, the Ascendant Perspective", Columbia, 1997</ref>

Complexity of an object or system is a relative property. For instance, for many functions (problems), such a [[computational complexity]] as time of computation is smaller when multitape [[Turing machine]]s are used than when Turing machines with one tape are used. [[Random Access Machine]]s allow one to even more decrease time complexity (Greenlaw and Hoover 1998: 226), while inductive Turing machines can decrease even the complexity class of a function, language or set (Burgin 2005). This shows that tools of activity can be an important factor of complexity.