Theoretical insights and experimental simulations suggest that life is a logical result of known chemical principles operating within the atomic and molecular realm. No new science is likely needed to understand life’s complexity, indeed life’s rise in complexity with evolution, provided we are willing to embrace the concept of non-equilibrium thermodynamics of open systems. When reduced to essentials, life isn’t much different, apart from its degree of complexity, than galaxies, stars, or planets. All these structured systems, including life itself, increasingly order themselves by absorbing energy from, and emitting entropy into, their surrounding environments. Time and energy are clearly key parts of Nature writ large. "Follow the energy" is as important a dictum as any in complexity science.
The cosmic-evolutionary story harks back to not merely the start of life but virtually the beginning of time. And it includes the scientific events that ordered the many complex systems—both living and non-living—now comprising the main characters in this story. Heraclitus of old, who basically had the right idea in his ancient philosophy that “all things change,” would nonetheless be amazed at the rich detail amassed to bolster today’s new scientific philosophy.
The specifics of life’s origin, however—thought to be a natural consequence of atoms and molecules interacting in an energy-rich environment—are not yet fully known, partly because the hard evidence was wiped clean billions of years ago and partly because laboratory experiments have yet to fashion chemicals more sophisticated than life’s precursors. In particular, a sizeable gulf separates the early evolution of life’s building blocks from the later evolution of the first living cells. This CHEMICAL EPOCH has sketched a scientific consensus concerning that blurred realm where chemical evolution ends and biological evolution begins.
What is clear is that the thermal gradients needed to foster energy flows in Earth’s biosphere could not be maintained without the Sun converting gravitational and nuclear energies into radiation that emanates outward into unsaturable space. Were outer space ever to become inundated with radiation, all temperature gradients would necessarily vanish and life among many other ordered structures on and beyond our planet would cease to exist. That space will never become saturated owes to the expansion of the Universe, bolstering the idea that the dynamical evolution of the cosmos is an essential prerequisite for the order and maintenance of all things—including, at least on Earth, the origin and evolution of life itself. All the more reason to include life within our cosmic-evolutionary worldview, for the observer in the small and the Universe in the large are not disconnected.
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