There is every reason now to see in the origin of life not a "happy accident" but a completely regular phenomenon, an inherent component of the total evolutionary development of our planet. The search for life beyond Earth is thus only a part of the more general question which confronts science, of the origin of life in the universe.

In: M Calvin and O.G. Gazenko (eds.), Theoretical and Experimental Prerequisites of Exobiology, Foundations of Space Biology and Medicine, Volume I, Theoretical and, Experimental Prerequisites of Exobiology, Chapter 7 (p. 321)