The Darwinian revolution is about essence. The Darwinian revolution is about who we are, it's what we're made of, it's what our life means insofar as science can answer that question.
Stephen Jay GouldForelimbs of people, porpoises, bats and horses provide the classic example of homology in most textbooks. They look different, and do different things, but are built of the same bones. No engineer, starting from scratch each time, would have built such disparate structures from the same parts.
Stephen Jay GouldAll evolutionary biologists know that variation itself is nature's only irreducible essence... I had to place myself amidst the variation.
Stephen Jay Gould