It’s important to define resilience and sustainability in ways that are both resilient and sustainable. If we do not, efforts toward creating these properties in a real world setting will always be aimed at a shifting target. Some of my [earlier posts](http://www.johnehrenfeld.com/2009/01/is-sustainability-becoming-ano.html) spoke about fears that sustainability and its cousin, greening, were in danger of becoming mere buzzwords. I certainly hope not. Jamais Cascio, [writing in Foreign Policy](http://www.foreignpolicy.com/story/cms.php?story_id=4851), adds to the confusion by miscategorizing the above two terms. Here’s his cut.
> Sustainability is inherently static. It presumes there’s a point at which we can maintain ourselves and the world, and once we find the right combination of behavior and technology that allows us some measure of stability, we have to stay there. A sustainable world can avoid imminent disaster, but it will remain on the precipice until the next shock.
> Resilience, conversely, accepts that change is inevitable and in many cases out of our hands, focusing instead on the need to be able to withstand the unexpected. Greed, accident, or malice may have harmful results, but, barring something truly apocalyptic, a resilient system can absorb such results without its overall health being threatened.
These terms are poorly used here. First of all, both are properties of complex systems. They are fundamentally descriptive of the system. They are both dynamic in the sense that they describe the ability of a system to continue to function in the face of changes to its environment. Sustainability is the general capability of a system to continue to produce some desired qualitative output. It is not, as Cascio writes, the maintenance of a system in a fixed state. For many years, the global financial system exhibited sustainability as it continuously produced confidence, security, and trust along with wealth in the form of money or monetized assets. But over that period the financial system changed dramatically in size and scope. Sustainability is always associated with some reified emergent property or with some real output; it never stands alone although we often do talk about it as if it does.
Resilience is the capability to maintain a system’s sustainability in the face of changes. It refers to the system, not the output properties. Given that the world is always changing in uncertain or unpredictable ways, it it difficult to imagine that a system that is not resilient will exhibit sustainability for long. In designing and governing large social-environmental systems both of these properties need to be built-in: sustainability in the sense that the system will produce whatever we want in the first place, and resilience so that the system will be able to withstand and adapt to changes as they come. For me, the system is the whole Earth for which sustainability is associated with the creation of flourishing for all life. Speaking about sustainability without referring to whatever is to be sustained lacks meaning in a practical sense.
Cascio has also written a [longer piece](http://www.fastcompany.com/blog/jamais-cascio/open-future/resilience) in Fast Company about resilience. Again he places sustainability in a secondary spot.
> You don’t have to be trying to come up with a new global economic model to appreciate resilience. Increasingly, the concept is taking root in organizations of all types as a strategic guideline, and becoming part of the language of design for everything from software to cities. In some circles, it’s starting to replace ”sustainability” as an environmental driver.
Resilience alone is never enough. If the system is not producing what you want, resilience is the worst design criterion. Antibiotic-resistant bugs display a form of resilience for which medical science is looking for ways to counteract it. When cultural change is needed as in the case of sustainability as flourishing, resilience is not a positive attribute.
For those interesting in learning more about complex systems and their properties, I recommend the book, [Panarchy](http://www.amazon.com/Panarchy-Understanding-Transformations-Natural-Systems/dp/1559638575), by Lance Gunderson and C, S. Holling.