“Complex” has both a colloquial meaning and a scientific one. Scientifically, it describes a system whose many interdependent parts interact nonlinearly, allowing behaviors to emerge that cannot be easily predicted from individual components. 

Biological systems like the immune system, the human brain, and ecosystems are complex, as are technological systems like large language models (LLMs) and our electrical grid. Even social systems like cities, economies, governments, and social networks share the scientific properties of complex systems. 

That’s how a single bankruptcy can trigger a widespread financial crisis, while the actions of a single protester can topple a regime. It’s the complexity of technological and social systems that our institute investigates.

But “complex” can also refer more colloquially to the kinds of thorny problems, from reforming our healthcare system to addressing climate change to managing a large-scale project at work, that have no obvious solution and involve difficult (and often unpredictable) tradeoffs. 

By looking at these thorny problems through the scientific lens of complexity, we can better make sense of them, and more clearly see a path forward.

Complexity and progress often go hand in hand. As economies mature, supply chains grow longer and more opaque. As financial systems mature, risks become more intertwined. As technology matures, it becomes less intuitive. As science matures, it becomes more specialized. As societies mature, their institutions and policies grow more complicated and interconnected.

In many ways, this is a good thing! We want to live in a world where people continue to innovate on the status quo. Simpler systems often leave a lot on the table; complexity is what has brought—and will continue to bring—increased productivity and prosperity. 

But we know from decades of research on complex systems that complexity brings challenges as well. Complex systems are more fragile, with hidden dependencies creating cascading effects and increasing the likelihood of “black swan” events. Complex systems also have an inherent degree of unpredictability that can be difficult for decision-makers to even comprehend, not to mention account for. 

In complex systems, trust in others’ expertise becomes more essential at the very same time that it becomes harder to maintain. And with trust so low, cooperation on a wide range of collective problems, from climate change to data privacy, becomes harder.