Nostalgia Just Became a Law of Nature

“Still and her collaborators showed how dissipation is bounded by the unnecessary information a system retains—information irrelevant to the system’s future behavior. With an admirable poetry of mind, they referred to this as nostalgia, the memories of the past that are useless for the future. What they showed is that the nostalgia of a system puts a minimum on the amount of work you will lose in acting on it.”

“Quite literally, work: Whirlpools set up when you jam down a piston are not (yet) lost—with careful tracing, one can jitter the piston back to recover their energy. It is only over time, as they break apart and become unknowable, as they become increasingly unpredictable to you, that the work that went into their creation is lost.”

“Here is the melancholy of a forgotten memory, a childhood room packed into boxes, the irrecoverable details of an afternoon drizzle, appearing quite literally in physical law. Those memories trace a past that no longer matters. Brought to our attention, they tell us a story of loss, and threaten to consume our present, if we’re not careful. In physics, too, nostalgia carries a penalty.”

“England’s work seems to explain why, over 3 billion years, our ecosystem turned into a giant green solar panel, feeding towers of herbivores and predators as part of a natural process that smears out the energy of the sun. We exist, in this interpretation, because we dissipate as reliably as possible the massive source of work at the center of our solar system. While Still’s work connects nostalgia to dissipation and loss, England’s work seems to say that life itself is brought into being by the demands of dissipation. Beings like us exist precisely because we create our worlds—physical, chemical, biological, mental, social—and tear them down faster than the alternatives. Nostalgia may be bittersweet, but it may also underwrite our existence.”