AI Is Life

Fernando Kaskais

May 3

Sanchit Sawaria for Noema Magazine

Technology is not artificially replacing life — it is life.

Sara Walker is an astrobiologist and theoretical physicist. She is the deputy director of the Beyond Center for Fundamental Concepts in Science and a professor in the School of Earth and Space Exploration at Arizona State University; external faculty at the Santa Fe Institute; and a fellow at the Berggruen Institute.

Toward the end of August 1924, the orbits of Mars and Earth carried the two sister planets closer to each other than they had been in around a century. Enthusiasm for the event spread across the United States. An article in the New York Times anticipated that astronomers "may definitively solve the question whether Mars is inhabited." The government requested five minutes of complete radio silence, on the hour every hour, across the nation over the days when the planets were closest to one another, with the hope that this radio silence would increase our chance of detecting any signals broadcast by Martians.

No message came.

As long as we have looked toward worlds that might be among the stars, we have hoped for and assumed life would be on them. Disappointment and shock greeted the news that there was no observable life revealed by the first images of the surface of Mars. Since then, we have grown accustomed to images of other barren worlds in the decades.

But could we recognize life if it is really out there? We are embedded in a living world, yet we do not even recognize all the life on our own Earth.

For most of human history, we were unaware of the legions of bacteria living and dying across the surface of everything in our environment — even within us. It took the technological innovation of the microscope in the late 16^th century for us to finally see a microscopic world teeming with life. The first indication we had of viruses was cryptic patterns in infectious diseases they cause, but their existence was only confirmed in the late 19th century. We also did not know about the ecosystems thriving near hydrothermal vents in the darkest depths of the ocean floor until the second half of the 20th century, when submarines that could stand intense pressures got us close enough to observe them.

"Attempts to define life have so far failed because they focus on containing the concept of life in terms of individuals rather than evolutionary lineages."

The discovery of new forms of life requires the advent of technologies that allow us to sense and explore the world in new ways. But almost never do we consider those technologies themselves as life. A microbe is life, and surely a microscope is not. Right? But what is the difference between technology and life? Artificial intelligences like large language models, robots that look eerily human or act indistinguishably from animals, computers derived from biological parts — the boundary between life and technology is becoming blurry.

A world in which machines acquire sufficient intelligence to replace biological life is the stuff of nightmares. But this fear of the artificiality of technology misses the potentially far-reaching role technologies may play in the evolutionary trajectories of living worlds.

Complex (technological) objects do not just appear spontaneously in the universe, despite popular folklore to the contrary. Cells, dogs, trees, computers, you and I all require evolution and selection along a lineage to generate the information necessary to exist.

Here on planet Earth, this is evident even in the rocks: Mineral diversity has co-evolved with life, for example through the process of biomineralization, in which organisms produce minerals to strengthen shells or skeletons or accomplish some other goal. The global rock record literally includes the fossilized remains of the history of life, because life has altered the geosphere so markedly. Because of this, we expect worlds with no life will have different compositions than the Earth does, even in the nonliving materials that compose them.

Many of us would not recognize mineral diversity as "life" any more than we would the computer screen or magazine you are reading this text on as "life," but these are products of a sequence of evolutionary events enacted only on Earth. This is as true for a raven as it is for a large language model like ChatGPT. Both are products of several billion years of selective adaptation: Ravens wouldn't exist without dinosaurs and the evolution of wings and feathers, and ChatGPT wouldn't exist without the evolutionary divergence of the human lineage from apes, where humans went on to develop language...

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