Image: 3D visualization suggesting DNA, a free to use Unsplash image by user Braňo.

John D. Morris, Ph.D., concludes a discussion of various methods for determining the age of the earth by noting how those methods that indicate young ages seem reasonably expected to be more reliable than those indicating ages sufficiently old to mesh with the time scale of evolutionary theory—though, he emphasizes, all the methods are limited by such doubtful assumptions as constant process rate (uniformitarianism). If only a witness to the earth’s origin had given us a written record we could use to determine earth’s age with greater reliability….

We have studied only a few of the many geochronometers which can be used to date the earth. These and many others…point to an age for the earth much too young to have allowed for evolution….Remember each ‘clock’ relies on the same basic assumptions as for radioisotope dating, (1) constant process rate; (2) relative isolation of the system, so no loss or gain of quantities has occurred; (3) knowledge of the initial state of the system; (4) the earth is at least old enough to have produced the present state through the observed process. Since all these assumptions are questionable…, and very likely wrong altogether given the historical facts of Creation, Fall, and Flood, we don’t expect any such geochronometer to give a valid age. However, it is reasonable to conclude that those geochronometers which make use of worldwide observations and systems (like magnetic field decay, helium in the atmosphere, and salt in the ocean [all of which indicate a young earth]), would be better, all things being equal, than those employing the dating of a single rock or local system [such as radioisotope dating]….It would also be better for a system to have a long-enough history of measurement behind it (like magnetic-field decay) to identify and smooth out any temporary fluctuations in the process rate. And, if the history of measurement of a particular system represents a significant portion of a half-life, it also lends credence to the method [true of magnetic-field decay; not true of the decay of such radioisotopes as Uranium-238]….It might even be reasonable to assume that the larger the ‘date’ derived by a particular system, the more opportunity there has been for contamination or alteration, which would yield an incorrect date….It seems reasonable [, then,] to conclude that while any chronometer, whether limiting or actual, would be untrustworthy, for each employs questionable assumptions about the unobserved past based on uniformitarianism, the weight of evidence does point towards a young earth, rather than an old earth. The only way we could know for sure how old things are would be if someone (or Someone) who saw these processes occurring made careful observations and recorded them for us….And that is exactly what we do have in Scripture.—John D. Morris, The Young Earth, pages 90-1 in the 1994 Master Books edition (1998 printing).