It is very easy to see that a rock and a chipmunk are different. The rock does nothing but slowly erode. Chipmunk, on the other hand, is a flurry of activity. It endlessly scans its environment for food or danger. And when one of them appears, the mokmunk is quick to react. At a more fundamental level, however, what really IS the difference between a dead rock and a very alive chipmunk? What is the difference in the level of physics and mathematical chemistry?
This question is at the heart of a three-day workshop on “Information-Driven States of Matter” that I’m co-hosting with Gourab Ghoshal and Artemy Kolchinsky next week at the University of Rochester. I’m really looking forward to the meeting, and today I want to give you a preview of some of the topics we’ll be exploring as they will surely drive future columns.
Information driven systems
Over the past few decades, physicists have increasingly come to see life as a unique “state of matter” that requires special consideration. It began 70 years ago when Edwin Schrödinger wrote his seminal work, What is life? In that little book, he asked whether living systems might require the development of new laws of physics. Although this remains a controversial question, many scientists who study life as a “complex system” have come to believe that living systems are unique in at least one remarkable way: they use information.
While the rock we were just thinking about might be describable in terms of information (for example, in the arrangement of its atoms), we are the ones who do the describing. The Rock couldn’t care less about the information. On the other hand, even a simple amoeba is capable of storing, copying, transmitting and processing information. Not only are cells capable of using information, they are also dependent on it. In this sense, they are information-driven: They must constantly acquire and use information from their environments to stay alive. It is also worth noting that some physicists used the term “active matter” to describe living systems, but the active part is about information.
In the workshop, we will take a broad view of our question about information-driven systems. At the largest scale, we want to understand life as an astrobiological phenomenon. To that end, we’ll host a talk by Caleb Scharf, of NASA’s Ames Research Center. Scharf’s work explores the concept of “computational zones”. If life requires information processing, what regions of the Universe have the physical conditions that allow computation? Along similar lines, but looking in finer detail, Manasvi Lingam of the Florida Institute of Technology will look at the constraints (ie limits) on the types of information processing that can occur in different planetary environments (e.g. ., hydrocarbon lakes on Titan, Saturn’s largest moon) .
We will also explore the specifics of how life on Earth uses information. Since much of life’s computational machinery is based on chemistry, Harvard’s Juan Perez Mercader will unpack the connections between biochemistry and information processing. At least for humans, the brain is the CPU for using information. That’s why Sarah Marzen of Claremont Colleges will ask how well neural systems of any kind (including artificial ones) can make predictions (such as those needed to stay alive in changing environments). Jordi Pinero, a post-doc in our collaboration, will explore how information processing needs can actually limit the growth of organisms.
However, no progress can be made in this field without the development of new and powerful mathematical tools that combine information theory and the physics, chemistry, and biology of complexity science. To that end, David Wolpert of the Sante Fe Institute will take a deep dive into the non-equilibrium statistical physics of computation and communication. His work pushes the boundaries of what we mean when we talk about physics and information together. And because the type of information you use is as important as the use of all of it, Damian Sowinski from our group in Rochester will take the workshop through our studies of semantic information, ie the importance of meaning.
These are just a sampling of the ideas we will learn about, discuss and debate (scientists like to argue). I can’t tell you how excited I am about this workshop. I hope we will come away with a new and better perspective on that powerful question that Schrödinger asked so long ago: What is life?
By the way, I plan to live-tweet (or live-X-ing, or whatever it’s called these days) the workshop at @adamfrank4 if you want to follow along (July 10-12). Also, big thanks to the Templeton Foundation for sponsoring the meeting.