By Joern Fischer
A picture is worth a thousand words — and an effective graphic can summarise complex relationships in simple terms. Perhaps the most famous graphical metaphor in sustainability science is the ball-in-cup metaphor used to communicate the concept of ecological resilience. What makes the ball-in-cup metaphor so powerful? And can the seesaw metaphor of leverage points (illustrated below) be equally powerful?
The ball-in-cup metaphor describing resilience — especially the bottom part of this figure has been very influential (Source: Kuei-Hsien Liao 2012, Ecology & Society)
Before we get to the seesaw metaphor of leverage points for sustainability, let’s “analyse” some of the key features of the ball-in-cup metaphor.
1. The ball-in-cup metaphor addresses an important issue that had been under-recognised. The concept of ecological resilience, when it was first raised, was new, and not entirely easy to understand to scientists or the public. People were used to thinking of the world as one that ought to be stable, and which, when “shocked”, would return to this stable state. The idea that a system might in fact “flip” into an alternative stable state was fairly different from what most people were thinking about. Today, thinking about these issues has culminated in the concept of “planetary boundaries”, that is, the notion that we might move our Earth system into an entirely different, and less livable, stable state. Most scientists and many members of the public can understand the idea of “planetary boundaries” — of moving outside the desired stability domain. Arguably, this would not have been the case without the “ground work” being done for a number of years by the simple ball-in-cup metaphor.
2. The ball-in-cup metaphor captures just enough complexity to be interesting, but no more. The concept of ecological resilience has many subtleties, which have in fact been captured graphically in various other ways. For example, some systems are characterised by hysteresis, that is, changes between alternative stable states that are not smoothly reversible. Also, systems may change their state not because of a shock, but because of a change in contextual conditions. Subtleties such as these can be drawn using the ball-in-cup metaphor, but not without some difficulties. It’s the basic ideas, however, that are most important to understanding ecological resilience, and that are captured really well by the ball-in-cup metaphor: (i) your system sits in one spot, but don’t take that as given; (ii) if you shock it a bit, it might recover and stay basically the same; but … (iii) if you shock it too much, it may flip into another state. This is relatively complex material to get your head around, but using the ball-in-cup metaphor, it’s fairly easy to explain.
3. The ball-in-cup metaphor makes intuitive sense. We get it: most of us have seen a ball roll down a hill, or be kicked over the top of one … and that’s about all you need, in terms of personal experience, to get this metaphor.
4. It’s imperfect, but not to the degree that it leads to wrong conclusions. The world is a lot more complex than a ball in a cup. Many of the mechanisms keeping the ball where it is — or driving it over the edge — remain hidden in this metaphor. Stability domains typically involve feedbacks to keep the system where it is. It’s the nature of these feedbacks (or new ones not previously operating) that drives system change, and causes regime shifts. One could criticise that these kinds of changes remain invisible in the ball-in-cup metaphor. It also doesn’t say anything about the nature of the drivers, and one might argue that thinking about the world as a simple ball ignores the fact that it’s the world itself that is dynamic — isolating the ball from its cup thus might be considered intellectually meaningless — when it comes to the Earth system, the ball and the cup are essentially the same thing, and even the people causing the changes (the drivers) are part of it. While these are potential criticisms, I’d just shrug them off in the sense that no metaphor can be perfect. But if it’s good enough to get an important point across, it can be powerful nevertheless.
So, what about the seesaw metaphor of leverage points for sustainability? The idea of leverage points dates back to a paper by Donella Meadows (as previously explained here). To communicate our research project on leverage points, we have simplified this using the graphical metaphor of a seesaw (in fact, the original credit goes to Dave Abson).
Meadows’ leverage points, depicted here using the metaphor of a seesaw.
How does this metaphor stack up against the features that seem to have made the ball-in-cup so useful?
Regarding point 1 — the importance of the issue at hand — I think we’re spot-on. Despite ever-increasing efforts, there is little sign that humanity (globally speaking) is moving towards sustainability, and there are plenty of signs that we’re moving away from it. A lot of what we’re doing is fiddling around the edges, while leaving some of the key issues unaddressed. In 1971, Ehrlich and Holdren spoke of environmental impact being a function of population, affluence and the technologies we use. Perhaps population is starting to level off, but hunger for affluence remains unsatisfied even among the richest, and in sum, the technologies humanity uses today are no less “impact-free” than several decades ago (though, of course, some technologies can alleviate the pressures caused by population and affluence). What’s missing from current solutions? Too many of the things we discuss don’t even go near those leverage points discussed by Meadows as the more influential ones. The system rules, the system goal, the paradigm driving the system, and the will to question it — addressing these things is where we could expect major change to come from. Not from adjusting constants or changing a few material flows. This point is both important and under-recognised.
Regarding point 2 — capturing enough complexity but no more — the seesaw metaphor is also quite useful. There are many things that this metaphor does not tell us, but there are also a few key things that it says quite immediately — push at the end of the seesaw, if you want to move it: we’ve been pushing in the wrong spot!
Regarding point 3, the seesaw is fairly intuitive. Perhaps not everybody has actually played on a seesaw … I suspect there are a lot more kids who kick around a ball than who sit on a seesaw! But as far as these things go, many of us have at least seen a seesaw in action, and so the metaphor is somewhat intuitive.
Regarding point 4: like the ball-in-cup metaphor, the seesaw metaphor is not perfect. Again, the complex system is being dumbed down to a “round thing”, and again, human agency sits outside that round thing (and not within it). Perhaps more importantly, the labels from low to high leverage points are driven by the expertise of one (albeit hugely experienced!) systems researcher, namely Donella Meadows. Despite her undeniable wisdom, her list of leverage points may not be perfect, and in her essay, she herself acknowledged that she had changed her mind on the relative importance of these leverage points through time. But that’s where research comes in: science ought to look at those things that are potentially important, but largely under-researched.
There’s no telling if the seesaw metaphor will speak to the world — and it would be crazy to even hope that it can be as successful as the ball-in-cup metaphor. But this isn’t a competition, after all! — It’s about getting important ideas across to as many people as possible.