Most conflicts in the world today are non-traditional. The technologically-driven forces of “creative destruction,” the nimbleness of the small, and the tendency of great powers to fight the next war with the mindset of the last one have radically changed the nature of modern warfare. So says Professor Yaneer Bar-Yam, the founder of the New England Complex Systems Institute. He has been a pioneer in studying the dynamics of complex systems in international development, military conflict and ethnic violence. In this week’s podcast he talks to WhoWhatWhy’s Jeff Schechtman about how even the task of defining the objective of war has to be reevaluated today. He explains how complex human biological systems can serve as models for understanding the new paradigm of warfare. The old paradigm — opposing armies lined up across clearly defined boundaries — has largely been superseded in a world where complex interactions are often played out among asymmetric antagonists. As Bar-Yam puts it, “

The United States and the Yemeni branch of al-Qaeda are sworn enemies. But along one battlefront in Yemen's civil war, they're fighting on the same side. The ancient city of Taiz is at the heart of Yemen's civil war, and despite efforts to maintain a ceasefire elsewhere in the country, fighting goes on in and around Taiz. The city is surrounded by an armed insurgent group known as the Houthis, who, with support from military strongman Ali Abdullah Saleh, took control of much of Yemen in 2015. Defending Taiz from the Houthi fighters are forces of the US-supported, Saudi-led coalition that includes ground troops from the United Arab Emirates and fighters loyal to Abdrabbuh Mansour Hadi (the Yemeni president who fled the country ahead of the Houthi tide). But there are also local militiamen and fighters from the Southern Movement — a secessionist group — and in recent months, fighters from Ansar al-Sharia, better known outside Yemen as al-Qaeda in the Arabian Peninsula. Each

The fighting had raged for three days. It wasn’t unusual for the city to come under attack, but it rarely lasted this long. This time, they were under siege. Rebel fighters on the city’s edge cut off water and surrounded most of the area. Still, Rana and her family never thought for a second the insurgents would break through. When the sound of gunfire outside finally quieted, the family expected things to go back to normal. It came as a shock when the crackling speakers of the mosque echoed in the streets outside. “We heard them declaring victory. It came out of nowhere,” Rana says. “At that point, we knew that the army had gone and that Nusra was here.” A little more than a year since Jabhat al-Nusra captured the Syrian city of Idlib, the group still retains control of the city and much of the surrounding area. An offshoot of al-Qaeda, its ideology is largely indistinguishable from that of the so-called Islamic State. And yet while ISIS has been significantly weakened by its enem