1. Based upon: Kelly, Kevin. 1989. Simple words about the new science of complexity: A talk with George Cowan. Whole Earth Review 63 (Summer 1989): 94-97.

2. WAYS OF LOOKING AT THE WORLD Humans tend to perceive things either holistically (as irreducible wholes) or reductionistically (as collections of simpler components) Both views have their merits However, we must also consider the INTERACTIONS between the components SYSTEMS THEORY

3. SYSTEMS systēma (Gr.) – organised whole a set of interacting or interdependent components forming an integrated whole many types and scales of systems, from subatomic particle interactions in matter, through metabolic systems in cells, up to star systems in the universe

4. SYSTEMS Ludwig von Bertalanffy (1901- 1972) was frustrated by reductionist thinking sought a unifying theory that would cover philosophy, psychology, physics, and chemistry

5. General Systems Theory one general organising theory to unite many different areas central tenet: all systems, however different, have similar underlying organising principles General Systems Theory extends from very simple nonliving systems (e.g., thermostats) to complex living systems (e.g., organisms, societies, institutions & cultures)

6. SYSTEMS open systems: exchange matter and energy with their surroundings -> most systems are open (living organisms, heat engines, etc.) closed systems: exchange energy, but not matter, with their surroundings (e.g., computer programs, planet Earth)

7. ALL SYSTEMS HAVE… Structure: components that are directly or indirectly related to each other Behavior: processes that transform inputs into outputs (material, energy or data);

8. ALL SYSTEMS HAVE… Interconnectivity: their parts and processes are connected by structural and /or behavioral relationships Boundaries: natural or defined limits which determine which parts are inside the system and which parts are outside

9. A PROBLEM ARISES!

12. Mid-1980s Desktop PC 1977 Apple II Desktop

14. ATTEMPTS TO DESCRIBE COMPLEX SYSTEMS IN TERMS OF THEIR SUBSYSTEMS, SHOWING HOW THE PROPERTIES OF THE SUBSYSTEMS ARISE FROM THE INTERACTION OF THE SUBSYSTEM PARTS

15. EMERGENT PHENOMENA EMERGENT PROPERTIES

16. e.g., Interaction of wind with the surface of the ocean results in WAVES interaction of lunar gravity with the surface of the ocean results in TIDES

17. Interaction of water with the surface of the sand results in RIPPLES

18. Interaction of win with the surface of the sand results in DUNES and RIPPLES

19. Computer simulation: THE FORMATION OF SAND RIPPLES BY WATER WAVES IN A UNIFORM CURRENT The model contains: topography grain size distribution grain volume compaction acoustic impedance Unpublished mathematical model, 2005 Dr. Peter Staelens (Brugge, Belgium) www: www.dotocean.eu contact: peter@dotocean.eu

23. AN EARLY EXAMPLE (1990s) FORETELLING CURRENT SYSTEMS :

24. Example: Seattle Traffic Flow Map http://www.wsdot.wa.gov/traffic/ seattlehttp://www.wsdot.wa.gov/traffic/ seattle

30. IMPLICATIONS:

31. Metastable ecosystem: Freshwater marsh (e.g., Cataraqui Marsh near Kingston, ON) Appears very stable and unchanging Little evidence of growth or renewal except for seasonal change from summer green to winter brown Actually one of the most productive ecosystems on the planet -> Rapid cycles of growth, senescence, decomposition -> high energy flows and quick cycling of materials

32. Wetland nutrient cycling and storage (yellow box) Wetland ecosystem components (boxes) Wetland ecosystem processes (arrows) From Hossler et al. 2011

33. : E.g. Audio feedback – Microphone picks up sound -> Amplifier makes it louder -> Speaker broadcasts it -> Microphone picks up sound -> Amplifier makes it louder -> Speaker broadcasts it -> Microphone picks up sound -> Amplifier makes it louder -> Speaker broadcasts it -> SHRIEK!!! SHRIEK!!! SHRIEK!!!SHRIEK!!!

34. E.g. Positive feedback in a natural system: Greenhouse gases in the atmosphere and climate change

35. UNCHECKED POSITIVE FEEDBACK LOOPS MAY TEND TO DESTROY THE SYSTEM THAT THEY ARE A PART OF

36. The heater kicks on, heating up a room Heat, the output of the heater, serves as input to the thermostat. At a certain critical temperature, the thermostat tells the heater that the room is warm enough. The heater, receiving this feedback through an electrical connection, shuts itself off. After a while, the thermostat notices that the room has cooled to a specific temperature, and notifies the heater. The heater kicks on again. The information traveling from the heater to the thermostat and back again is a negative feedback loop. : Thermostat Heater E.g. HEATER AND THERMOSTAT

37. E.g. Negative feedback in a natural system: Cycles in lynx and hare populations

38. NEGATIVE FEEDBACK LOOPS MAY TEND TO STABILIZE THE SYSTEM THAT THEY ARE A PART OF

39. INTERACTIONS BETWEEN NEGATIVE AND POSITIVE FEEDBACK LOOPS IN A SYSTEM CAN RESULT IN DYNAMIC EQULIBRIUM