Book Reviewed: From Matter to Life: Information and Causality, Edited by Sara Imari Walker, Paul Davies and George Ellis

Maxwell’s Demon of a living cell

The cosmos is like a computer, and the information about matter and energy is processed in this computer to make physical reality. But the idea of “information” makes sense only to a conscious observer according to quantum physics. Classical/relativistic physics affirms that reality exists independent of conscious observers. In recent years, thermodynamics and the information dynamics have refined our understanding of physical reality.

In thermodynamics, entropy is related to a concrete process, but in quantum mechanics, this translates into the ability to measure and manipulate a system based on the information gathered by this measurement. A well-known example is Maxwell’s demon. Like life, Maxwell's imaginary demon seems to violate the second law of thermodynamics. But on careful examination it doesn't, so long as information is treated as a physical resource, an additional fuel.

In this book, physicist Paul Davies applies information as the key to understand life. Simple elements assemble to form molecules and then turn into life. But non-living matter also consists of the same atoms, then how do we explain this conversion? Non-life to life? Life is generally defined by its hallmarks: reproduction, harnessing energy, responding to stimuli, etc. But that doesn’t tell us what life is. We may know all about the complete genome of a mouse, but we don’t know what it is like to be a mouse!

The information flow in genetics is complex. This is illustrated in an experiment that chops the head and tail of a worm and applying electricity, which disrupts the information flow in regrowth. This results in a worm with a head at both ends, and they reproduce with those physical traits, even though they have the same DNA as the original one-headed worm!

Life is marked by a remarkable transformation in the organization of information facilitated by the operation of laws of physics. The cellular dynamics that includes complex biochemical reactions occurring in a concerted manner to support life. Genes, the molecular components of hereditary materials are read, decoded and translated into proteins. Then “life” uses these informational pathways for regulation and functioning of cells. Treating information as a physical quantity formulate "laws of life" that transcend life's physical substrate. This is where non-life is turning into life, but it is the information dynamics and not mere matter to matter transformation!

The authors take a cross-sectional view of quantum physics, chemistry, nanotechnology and information processing considering hardware (physics and chemistry) and software of life (biology). They don’t describe the nature of biological Maxwell Demon nor we can measure any of its physical attributes.

The first two chapters, Introduction; and the "Hard Problem" of Life by Sara Imari Walker and Paul Davies, Chapter 15. Biological Information, Causality, and Specificity - An Intimate Relationship by Karola Stotz and Paul E. Griffiths; Chapter 13. Living through Downward Causation - From Molecules to Ecosystems by Keith D. Farnsworth, George F. R. Ellis, and Luc Jaeger are interesting chapters. A college level physics, and biology would be helpful to appreciate this book.