7.16

## University of Groningen

Skip to 0 minutes and 9 secondsIn this lecture, we're going to look again at a city with various examples. Examples that make clear that our urban lives are not always extremely ordered, our lives are neither full of chaos. Life quite often evolves between these two, between order and chaos. And these developments we call nonlinear. What we're going to look at is a few examples of transitions, of jumps between stable periods. We will see patterns emerging, nonlinear patterns, patterns that emerge out of transitions. Let's have a look. For our purpose, we define a city as a complex, adaptive system. This brings us a handful of interesting notions; emerging patterns, self-organization, path dependency, co-evolution, adaptivity, et cetera.

Skip to 1 minute and 7 secondsWhat relates to it as well is a transition, a jump between two stable phases, a jump with structure and function co-evolving. In this example, we see a white circle evolving into a gray square. The circle and the square represent structure. The colors, white and gray, represent function. To switch from white circle to gray square is a very abstract presentation of what is happening in a transition. The difficulty is we cannot a priori predict into what the white circle can transform. In this case, the result is a gray square. How to make such a transformation physical in practice, one of my favorite examples is the bike. In this example we will not see a transition upward, but a transition downward.

Skip to 2 minutes and 3 secondsBut it makes perfect sense. And the good thing about this example is that you're aware of the behavior I'm going to show. You've all been part of such a transformation. Please consider this sign carefully. The sign is there because of local authorities explaining to you that something is going on ahead which blocks the route you're taking. Therefore, the advice is to turn right, as the authorities have developed for you a wonderful, alternative route. It will bring you as well to where you wanted to go. But what is happening in our world of anarchy in which we often ignore the rules? We ignore the signs.

Skip to 2 minutes and 46 secondsIt could even create dangerous situations, if the advice given by the local authority is not being followed up. This is the path the authorities advise you to go. The picture shows two bikers, which is very much in contrast of the situation, as hardly anyone is willing to follow the alternative route proposed by the authorities. Here you see the reason why the authorities ask you to take the alternative route to the right. They are repairing the road. You can't go on. That's absolutely clear. Please do go back. We are repairing for you the road, and in time we will present you a wonderful new bike path. But what is happening instead? There you go. This is what we call self-organization.

Skip to 3 minutes and 36 secondsWithout agreements, among the group of bikers, a bike path emerges as a new stable trajectory aside the common path, which is now under repair. We all are aware of his behavior. We all, more or less, behave the same. And we don't need negotiation with other bikers to go through the grass along the bike path, ignoring the authority's advice. There you go, a wonderful temporary bike path, at least as long as it is not raining, a stable bike path on a lower level of quality. In general these self-organized paths are being called elephant paths. They are there because individuals take the same route without negotiating this with each other, without coming to joint agreements. Nevertheless, there is a collective result.

Skip to 4 minutes and 35 secondsThese paths are a consequence of autonomous processes. And that is what we call self-organization. It is one of the characteristics of nonlinear behavior.

# The urban between order and chaos

This lecture explores the evolution of cities somewhere between order and chaos. When cities evolve both their function and structure evolve together. Are we able to know what the city will look like?