An apparently strong argument for an old earth is the seeming agreement between multiple (and supposedly independent) dating methods which yield "millions of years." Uniformitarian scientists claim that chemical clues within the seafloor sediments tell a "story" of climate change over millions of years and that this "story" agrees well with expectations of the astronomical (or Milankovitch) theory of Pleistocene ice ages. Yet secular scientists routinely use the astronomical theory to date the seafloor sediments in a technique called "orbital tuning." Of course, this argument is circular, since the astronomical theory of ice ages is simply assumed to be correct and is used as a framework for interpreting chemical clues within the seafloor sediments. Secular scientists have recognized the circularity in this argument and have attempted to guard against it by using "independent" checks on the orbital tuning method. However, these checks are not truly independent, as they all assume the old-earth, evolutionary paradigm. Moreover, the different dating systems are calibrated to one another: dates assigned to the seafloor sediments are used to date the ice cores, and vice versa. In fact, the dating of the ice and seafloor sediment cores is a gigantic exercise in circular reasoning.