Most people slow down with age. Adrian Bejan just acquires new degrees of freedom.

His latest book, Diversity through Freedom (Springer, 2026), takes that same physics and points it at a very modern argument. The idea: diversity isn’t something you legislate into existence, it happens naturally when things (rivers, animals, people) are free to change shape in response to how they move. As Bejan turns 78 this year, the principle behind evolution turns 31. He calls it the Constructal Law. Turns out nature figured out flow way before anyone wrote a mission statement about it.

A serial rebel that help demystify the Thermal and Natural Sciences, Prof. Bejan flipped Second Law analysis to hunt down wasted energy instead of just balancing it, popularized scale analysis as a cost-effective method to skip partial differential equations and get straight to the physics, wrote the book on convection in porous media, then formalized the Constructal Law, the idea that rivers, lungs, and lightning branch the same way because that’s how flow evolves. He took it mainstream with Design in Nature, then pushed it into economics and society with Freedom and Evolution. Every time, he took a field comfortable with “that’s just how it’s done” and made it explain why.

Happy birthday, Adrian. Keep making the majority of one shine through the noise.

Happy 78th Birthday, Adrian Bejan!