10 - Is It Possible to Scientifically Reconstruct the History of Life on Earth?

Summary

The data-based study of long past events and processes is common throughout the sciences. Some examples are the astrophysical hypotheses that the universe began with a cosmic explosion (“big bang”), which is supported by measurements of the cosmic microwave background radiation pervading the modern universe; the hypothesis that the end-Cretaceous mass extinction was caused by a meteorite impact, which is supported by an iridium anomaly and large quantities of shocked quartz in K-Pg (Cretaceous-Paleogene) boundary sediments; and the hypothesis that all life on Earth shares a common ancestor, which is supported by analyses of shared segments of ribosomal RNA found in contemporary organisms. My interest in the methodology of the historical sciences and how it differs from that of stereotypical or “classical” (as I later dubbed it) experimental science was first piqued in the 1990s by the writings of so-called “scientific [more accurately, biblical] creationists.” Scientific creationists and their successors, members of the “Intelligent Design Network,”¹ extol classical experimental research (the testing of hypotheses under controlled laboratory conditions) as the paradigm of good science, contending that historical scientific research is inferior because it uses “a form of abductive reasoning that produces competing historical hypotheses, that lead to an inference to the best current explanation rather than to an explanation that is logically compelled by experimental confirmation.”² Proponents of intelligent design are not alone, however, in denigrating the work of historical scientists. Articulating a view held by a surprising number of experimentalists, Henry Gee, at the time a senior editor of Nature, declared that no science can be historical because conjectures about the past cannot be tested by means of controlled laboratory experiments (Gee 1999).