Chance and the Persistence of Life
We call these events [DNA copy errors and genetic mutations] accidental; we say that they are random occurrences. And since they
constitute the only possible source of modifications in the genetic text, itself the sole repository of the organismís hereditary structures, it necessarily follows that chance
alone is at the source of every innovation, of all creation in the biosphere. Pure
chance, absolutely free but blind, at the very root of the stupendous edifice of evolution: this central concept of modern biology is no longer one among other possible or even conceivable hypotheses. It is today the sole conceivable hypothesis, the only
that squares with observed and tested fact.
[Nobel laureate Jacques Monod 1972]