While there is no rigorous definition of complexity, it is typically characterized by a system containing a collection of many interacting objects or agents, each with behaviour affected by memory or feedback, that can lead to unexpected outcomes.
A car is complicated but not complex, i.e. it does not exhibit unexpected behaviour by design. Traffic is complex but not complicated.
By definition, social systems are always complex.
- Johnson, N.F. (2007). Two’s Company, Three is Complexity.
- Adami, C. (2002). What is complexity? BioEssays, 24(12), 1085-1094.
- Simon, H. A. (1991). The architecture of complexity. In Facets of systems science (pp. 457-476). Springer, Boston, MA.
- Ito, J. (2021). Resisting Reduction: A Manifesto. Journal of Design and Science (JoDS). MIT.