“Life is a copiously branching bush,” Gould writes, “continually pruned by the grim reaper of extinction, not a ladder of predictable progress.”

Walker thinks that our understanding of life, as a phenomenon, is right now where we were with gravity before Newton. We can describe what we see, but we have no sense of the underlying principles—we just see an apple falling to the ground. She thinks that without a theory, a deeper understanding of what life is, the search for it beyond Earth is p

“I think that really misses the point, mainly because, if you think about it, the most important thing we’re doing in this century is inventing our successors.” He thinks that most of the intelligence in the universe, abundant as it may be, is likely synthetic.

He offers two lights to guide us: the warm light of community and “the cold light of the stars,” as from that cosmic perspective—that which the whole book has been written to offer—our struggle seems not less meaningful but, somehow, more. Stapledon illustrates a path and prescription, a vision of advancement that values creativity, communication,

but for the Oankali, genetic manipulation is not distinct from nature. In fact, all of their technology, including their starfaring ship, is alive, engineered and grown from natural forms.

“Science is not a collection of facts,” he said, but “a way of looking at the universe. And so by analogy, good science fiction isn’t only fiction which adheres to a specific body of facts, it can also be fiction that adheres to a certain way of thinking about the universe.”

Earth sometimes seems like the most habitable planet possible—not just for us but possibly at all.

If those molecules bump together and form something more complex, on and on, Cronin said, “that is the selection equivalent of gravity. And that process of complexity generates everything we have in the universe that’s associated with life.”

inciting reactions—and tracking the evolution of complexity. Because that, Cronin believes, is the entirety of life.