Introduction to Complex Systems

For each of the following examples, describe whether it can be best understood within the reductionist paradigm or the complex systems paradigm, and explain why.

• A bottle of water
• A single living cell in an organism
• A toaster

A city’s inhabitants form a complex social system. We can generally predict with high levels of confidence and reliability how busy the roads and public transport systems will be at certain times of day. How does this kind of predictability differ from what we can predict about a simple system?

For each of the following phenomena, identify which hallmark(s) of complexity it demonstrates and explain your answer.

1. A flock of starlings forming large-scale structured patterns in the air.
2. A train track is blocked by fallen trees after an intense storm and needs to be cleared. A replacement bus service is offered until the trains are able to run again.
3. In many sports teams, different players are assigned different roles. However, there are usually multiple players responsible for each task, such as defending and attacking. Additionally, there are reserve players, who can be brought on if a player gets injured, for example.
4. A phenomenon called Metcalfe’s law, which was originally derived from the study of computer networks, proposes that a network’s power is proportional to the square of the number of participants (such as individual computers or people) within it.
5. Economic bubbles in financial systems often occur when a particular asset’s value begins to rise, incentivizing more investors to buy it, believing that its value will continue to increase. However, its price cannot continue to rise forever, and, at some point, such bubbles usually “burst” relatively suddenly, creating shocks within the economy.