The origin of life is the deepest mystery in the whole of science. Many books and learned papers have been written about it, but it remains a mystery. There is an enormous gap between the simplest living cell and the most complicated naturally occurring mixture of nonliving chemicals. We have no idea when and how and where this gap was crossed. We only know that it was crossed somehow, either on Earth or on Mars or in some other place from which the ancestors of life on Earth might have come.
– Freeman J. Dyson, A Many-Colored Glass: Reflections on the Place of Life in the Universe (Charlotteseville, VA: University of Virginia Press, 2010), 104.