Through the comparison between two major, long-lasting theoretical frameworks-geocentrism and genocentrism-we discuss the different epistemological role played by metaphors in physics and biology. Throughout its history, physics developed theories and mathematical formalisms, which either do not seem to rely on metaphors at all (as geocentrism) or have absorbed initial thrusting metaphors into original theoretical frameworks. When considering genocentrism, in turn, the situation looks different. For some authors, genocentric theories are not metaphorical, but for opposite reasons with respect to geocentrism: pivotal concepts of information theories are straightforwardly imported as theoretical ones into biology. For others, the reference to information in genocentrism is indeed metaphorical, although the similarities and dissimilarities are not spelt out. Some problematic consequences of the application of genocentrism to biology are discussed.