The absence of fossil evidence for intermediary stages between major transitions in organic design, indeed our inability, even in our imagination, to construct functional intermediates in many cases, has been a persistent and nagging problem for gradualist accounts of evolution.
Stephen Jay GouldEvolution is one of the two or three most primally fascinating subjects in all the sciences.
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 GouldThe history of life is more adequately represented by a picture of 'punctuated equilibria' than by the notion of phyletic gradualism. The history of evolution is not one of stately unfolding, but a story of homeostatic equilibria, disturbed only 'rarely' (i.e. rather often in the fullness of time) by rapid and episodic events of speciation.
Stephen Jay Gould