Jabr's brief survey of attempts to define life, sweeping from Aristotle to NASA’s exobiology program, arrives at the frighteningly convincing conclusion that life cannot be defined.
"Even today, scientists have no satisfactory or universally accepted definition of life," Jabr says. "While pondering this problem, I remembered my brother’s devotion to K’Nex roller coasters and my curiosity about the family cat. Why do we think of the former as inanimate and the latter as alive? In the end, aren’t they both machines?"Things get even more interesting when you consider how this speaks with Krulwich's examination of our love of the comically intricate machines Goldberg dreamed up. For Krulwich, what fascinates us is the way some element of life peeks out from the Goldberg machines' mechanical chaos. As he puts it, "What makes a Rube Goldberg machine so charming, so familiar, is that they are so quietly biological."
To be clear, Krulwich points to an example that literally relies on living things to operate. (In this case, a "hungry fly" helps you snap a photo of yourself.) But I think he is onto something larger here. Add in a dash of Jabr's insight, and it seems clear that the more complex they get, the more those Rube Golberg machines seem to teem with life. Like Jabr's brother's K'nex roller coasters, Rube Goldberg machines resemble life because of their complexity.
Krulwich hits on this in his closing, which draws the mechanical and biological together in a manner that would likely leave Jabr nodding his head:
"And, of course, the deeper you look into anything (be it the heart of a cell, or the guts of some complicated machine), not only do you find intricacy and beauty, but sometimes you'll also discover something so improbably — so wonderfully — odd, that all you can do is laugh.Ironically, all of this takes me not further, but rather closer to a definition of life with which I can live (or at least operate). Instead of being defined by an undeniable divine spark, life might just be a matter of improbable mechanical complexity.
But Rube Goldberg knew that too."