Wonderful Life: The Burgess Shale and the Nature of History by Stephen Jay Gould

"Life is a copiously branching bush, continually pruned by the grim reaper of extinction, not a ladder of predictable progress." (35)

"Perhaps the grim reaper of anatomical designs is only Lady Luck in disguise. Or perhaps the actual reasons for survival do not support conventional ideas of cause as complexity, improvement, or anything moving at all humanward. Perhaps the grim reaper works during brief episodes of mass extinction, provoked by unpredictable environmental catastrophes (often triggered by impacts of extra-terrestrial bodies). Groups may prevail or die for reasons that bear no relationship to the Darwinian basis of success in normal times. Even if fishes hone their adaptations to peaks of aquatic perfection, they will all die if the ponds dry up. But grubby old Buster the Lungfish, former laughingstock of the piscine priesthood, may pull through -- and not because a bunion on his great-grandfather's fin warned his ancestors about an impending comet. Buster and his kind may prevail because a feature evolved long ago for a different use has fortuitously permitted survival during a sudden and unpredictable change in rules. And if we are Buster's legacy, and the result of a thousand other similarly happy accidents, how can we possibly view our mentality as inevitable, or even probable?" (48)

"Most of us are not naive enough to believe the old myth that scientists are paragons of unprejudiced objectivity, equally open to all possibilities, and reaching conclusions only by the weight of evidence and logic of argument. We understand that biases, preferences, social values, and psychological attitudes all play a strong role in the process of discovery. However, we should not be driven to the opposite extreme of complete cynicism -- the view that objective evidence plays no role, that perceptions of truth are entirely relative, and that scientific conclusions are just another form of aesthetic preference. Science, as actually practiced, is a complex dialogue between data and preconceptions." (244)

(New York: W.W. Norton & Company, 1990)