Our contention is that, despite the remarkable complexity of living order, the aggregate function of the biosphere is a simple one: it opens a channel for energy flow through a domain of organic chemistry that would otherwise be inaccessible to planetary processes.
Smith, Eric. The Origin and Nature of Life on Earth (p. 28). Cambridge University Press. Kindle Edition.
This has implications for the probability of life occurring on other planets and in the Universe. The alternate view is that its origin on Earth was something of a freak accident.
The fundamental idea is that free energy flows tend to create complexity, and that life is something of a phase change, or perhaps a series of phase changes.