There's no guarantee that extraterrestrial life will look like us, just with green blood and pointy ears. Alien biochemistries may not even use the same molecular components as Earthly life does. Definitions of life based on material constraints, therefore, may be overfitted to life as we know it. Thinking only of Earthly life may narrow the scope of scientific inquiry, shielding us from discoveries hiding in plain sight.
Motivated by the need to paint a more general picture of what life is—and could be—with respect to the rest of the phenomena of the universe, Stuart Bartlett and I introduced lyfe, a new definition of life based on four fundamental processes that characterize the living state, namely: dissipation, autocatalysis, homeostasis, and learning.
In a more recent contribution, we proposed tentative criteria for a more general and expansive characterization of habitability that we call genesity. Whereas habitability describes the environmental parameters required to merely sustain life as we know it, genesity describes the conditions that might promote lyfe's emergence and continual evolution.
Artwork by Cecilia Sanders
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