Life, not particles, may be physics' next great frontier
Sara Walker says new physics lies in the problems of life and intelligence rather than high-energy physics, Sean Carroll has shifted from guessing new laws to studying how complexity emerges, and Adam Frank calls the question of what life is the biggest question in physics. Three researchers independently pointing to the same frontier suggests where the next big breakthroughs may come from.
What frontier do the three physicists point to? Show answer
Life, complexity and information: how matter organizes itself, carries information and innovates, as opposed to smaller particles or higher energies.
What is Sara Walker's definition of life? Show answer
The process of how information structures matter over time and space.
Why does Walker doubt that particle physics holds the deepest answers? Show answer
She thinks so-called fundamental particles mark the limits of our instruments and that reality may have no final ground.
What does assembly theory measure? Show answer
The minimum number of steps needed to build an object and the number of identical copies that exist.
What threshold has been found for organic molecules? Show answer
Molecules needing more than about 15 steps appear in high abundance only when produced by life.
How does Sean Carroll describe his change of research direction? Show answer
He calls his earlier papers guesses about altered laws of physics and now studies how complexity emerges from a simple early universe.
How does Carroll relate complexity to entropy? Show answer
Entropy always increases, but complexity starts low, rises and then falls. Life exists in the middle period and feeds on low-entropy fuel.
What does Carroll think is the key to complexity? Show answer
Information. Parts of the universe learn to use information to survive and thrive.
What does Adam Frank call the biggest question in physics? Show answer
What life is, and in particular how an autonomous agent arises.
What contrast does Frank draw between stars and cells? Show answer
Physics can predict a star's entire life from its mass and composition, but not what a single cell's descendants will become.
On what do the three disagree? Show answer
Whether entropy explains life, how to interpret quantum mechanics, whether everything is physical, and the nature of consciousness.
What cautions does the article attach to this convergence? Show answer
The three are connected colleagues, there is no settled theory, other areas of physics are not finished, and evidence standards still apply.