To establish evolutionary interrelatedness invariably requires exhibiting similarities between organisms. Within Darwinism, there's only one way to connect such similarities, and that's through descent with modification driven by the Darwinian mechanism. But within a design-theoretic framework, this possibility, though not precluded, is also not the only game in town. It's possible for descent with modification instead to be driven by telic processes inherent in nature (and thus by a form of design). Alternatively, it's possible that the similarities are not due to descent at all but result from a similarity of conception, just as designed objects like your TV, radio, and computer share common components because designers frequently recycle ideas and parts. Teasing apart the effects of intelligent and natural causation is one of the key questions confronting a design-theoretic research program. Unlike Darwinism, therefore, intelligent design has no immediate and easy answer to the question of common descent.Darwinists necessarily see this as a bad thing and as a regression to ignorance. From the design theorists' perspective, however, frank admissions of ignorance are much to be preferred to overconfident claims to knowledge that in the end cannot be adequately justified. Despite advertisements to the contrary, science is not a juggernaut that relentlessly pushes back the frontiers of knowledge. Rather, science is an interconnected web of theoretical and factual claims about the world that are constantly being revised and for which changes in one portion of the web can induce radical changes in another. In particular, science regularly confronts the problem of having to retract claims that it once confidently asserted.
Evolution endowed us with intuition only for those aspects of physics that had survival value for our distant ancestors, such as the parabolic orbits of flying rocks (explaining our penchant for baseball). A cavewoman thinking too hard about what matter is ultimately made of might fail to notice the tiger sneaking up behind and get cleaned right out of the gene pool. Darwin’s theory thus makes the testable prediction that whenever we use technology to glimpse reality beyond the human scale, our evolved intuition should break down. We’ve repeatedly tested this prediction, and the results overwhelmingly support Darwin. At high speeds, Einstein realized that time slows down, and curmudgeons on the Swedish Nobel committee found this so weird that they refused to give him the Nobel Prize for his relativity theory. At low temperatures, liquid helium can flow upward. At high temperatures, colliding particles change identity; to me, an electron colliding with a positron and turning into a Z-boson feels about as intuitive as two colliding cars turning into a cruise ship. On microscopic scales, particles schizophrenically appear in two places at once, leading to the quantum conundrums mentioned above. On astronomically large scales… weirdness strikes again: if you intuitively understand all aspects of black holes [then you] should immediately put down this book and publish your findings before someone scoops you on the Nobel Prize for quantum gravity… [also,] the leading theory for what happened [in the early universe] suggests that space isn’t merely really really big, but actually infinite, containing infinitely many exact copies of you, and even more near-copies living out every possible variant of your life in two different types of parallel universes.