Before Charles Darwin, God was seen as the ultimate cause of all design, or the ultimate answer to 'why?' questions. John Locke argued for the primacy of mind before matter,[5] and David Hume, while exposing problems with Locke's view,[6] could not see any alternative.
Darwin provided just such an alternative: evolution.[7] Besides providing evidence of common descent, he introduced a mechanism to explain it: natural selection. According to Dennett, natural selection is a mindless, mechanical and algorithmic process—Darwin's dangerous idea. The third chapter introduces the concept of "skyhooks" and "cranes" (see below). He suggests that resistance to Darwinism is based on a desire for skyhooks, which do not really exist. According to Dennett, good reductionists explain apparent design without skyhooks; greedy reductionists try to explain it without cranes.