Life's clockwork: Scientist shows how molecular engines keep us ticking
In the popular book The Demon in the Machine, physicist Paul Davies argues that what's missing in the definition of life is how biological processes create "information," and such information storage is the stuff of life, like a bird's ability to navigate or a human's ability to solve complex problems. The "Demon" Davies refers to is Maxwell's Demon, as proposed by 19th century physicist James Clerk Maxwell as a thought experiment. Maxwell's hypothetical "demon" controls a gate between two chambers of gas and knows when to open the gate only to allow gas molecules moving faster than average to pass through it. This way, a chamber could be heated and create "energy" to be put to work. Such a demon would amount to a workaround of the Second Law of Thermodynamics. And that, as we know, is impossible. We also know, of course, that demons don't exist.