“It's not true that under any definition of order or disorder, things get disordered. In fact, very often in nature, things left alone get ordered. … If you look at frost, the beautiful ordered structure — who ordered them? … So the idea that entropy is disorder: careful.”
Into the Impossible With Brian Keating · Ideas & Essays · September 2026
Brian Keating opened by asking Rovelli to explain the frost on a window — how things left alone can become more ordered. Rovelli's answer is that entropy is not the same thing as disorder, and he ran through oil separating from water, a shaken box of balls settling to the bottom, and a beach sorting its grains from its stones. He thinks this is a case where popular science is bad, and where physicists are often confused themselves.
Transcript
It's not true that things get disordered. In fact, very often in nature, things left alone get ordered. To imagine that to be free, you have to violate the laws of nature is stupid. You, Brian, can be in a superposition. You can be in LA and also in San Francisco. Your head is older than your feet.
…me. He blew my mind by telling me that my head is older than my feet. And then he told me, why that's the least strange thing he was going to say. So Carlo, let's start with the frost. You're telling me that things left alone can get more ordered? That's not what I was taught. Walk us through that.
…dear to me. We always make this story, okay? Take like latte, calf, coffee, and mix, and look, they mix. In fact, take water and vinegar, put some vinegar in water, mix, and you know, they mix. Now, take water and oil, mix, they separate. Oh, yeah? So is this contradicting our entire understanding of the universe? No, it's just things a little bit more complicated than the way they usually said. It's not true that under any definition of order or disorder, things get disordered. In fact, very often in nature, things left alone get ordered. And oil and water separating is one of the many examples of that. If you have a box with balls you shake and then you put it there on the table, all the balls go very nicely in order on the bottom. Okay? They order themselves. If you look at a beach, the ocean, all the little grains are together and the big stones are another side of the beach. They order by the same. Who ordered them? Okay? If…
Let's talk about the early universe. You already mentioned the block
universe and Our mutual distaste of that hypothesis. I don't like that. I want to ask the why question. I really, I do want to ask the why question, but I know why questions are not usually answerable. But the universe was somewhat lower entropy, right? It was in a very special configuration. Does…
Yeah. Yeah, the two are very, very connected. It's not that one explains the other one, because we need an explanation for either. I think the past law entropy and the arrow time, psychological thermodynamics, are different manners of explaining, of pointing out to the same phenomenon about which I…
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