Is Geology in a Scientific Revolution?

The editors of a leading geology journal consider the possibility that one of their core concepts is a mere paradigm.

Thomas Kuhn left an indelible mark on philosophy of science with his 1962 bombshell book, The Structure of Scientific Revolutions. Kuhn was the one who gave us the phrase “paradigm shift” and the portrayal of scientists working in guilds, beholden to their colleagues, unable to think outside the box of conventional theories that may or may not have anything to do with reality. Many scientists working under the assumption of “scientific realism” pretend Kuhn’s concerns have been dealt with, but his name turned up once again in a rare case of self-examination by editors of a journal that should represent rock-solid realism: the journal Geology.

The occasion was a re-examination of a core principle in geology, the study of “sequence stratigraphy.” This important branch of geology interprets the time sequence of strata between unconformities. The basic idea is that each layer was deposited after the one below; it’s intuitive, simple, and straightforward. It can be represented in 2-D models. There may be dips in the strata, but each one was laid down depending on the sediment supply and the ability of a landform to accommodate it, perhaps as sea levels rose and sank over time.

Now, that simple model has come under question by Andrew Madof and two colleagues in a paper in Geology, “Nearshore along-strike variability: Is the concept of the systems tract unhinged?”

Sequence stratigraphic models assume that nearshore strata have relatively consistent and laterally persistent stacking at the systems tract scale and therefore may not fully describe the three-dimensional stratigraphic architecture in areas displaying marked nearshore along-strike variability. A stratigraphic model of nearshore deposits is presented that corrects for this assumption by explaining variations in along-strike stratal geometries in terms of a systematic change in the orientation of a shoreline trend or clinoform rollover, a scenario comparable to deflection around a hinge. The model defines hinge zones that are both fixed and moving with respect to time, and was created from outcrop, well-log, and seismic reflection data. Model end members predict contemporaneous progradational, aggradational, and retrogradational stacking bounded by surfaces displaying significant along-strike changes in architecture, implying that sequence stratigraphic surfaces can be diachronous.

The details may be of interest to specialists. Suffice it to say that the Editors of Geology were impressed enough to conjure up the spirit of Kuhn over this sea change in thinking. Their concerns are expressed in an open-access editorial, “The future of the sequence stratigraphy paradigm: Dealing with a variable third dimension.” They ask if sequence stratigraphy is a method, a model, or a paradigm.

So is sequence stratigraphy a method, or a model, or both? Following on from this it is important to ask, after just over 50 years of development since the original work of Sloss (1949,), how should the method and model continue to develop? To answer these questions, it is perhaps useful to think of sequence stratigraphy as a paradigm; that is, a framework of theories, methods, postulates, and standards for what constitutes a legitimate contribution to a field of science (Kuhn, 1962). As a paradigm, sequence stratigraphy is both method and model, and it is certainly possible in this case to progress from careful, objective observation to interpretation following certain theoretical models. However, it is also possible, as Kuhn (1962) points out, that the paradigm dominates thinking and observation, to the extent that it can make sufficiently objective observation and independent testing of the model elements difficult. In which case, it is very important to constantly review the various elements of the paradigm to check that they are performing well, and to encourage modifications or additional elements, to include new developments from theory and experiment, and to address relatively weak areas. Madof et al. is an example of a possibly useful additional element to the method, and this and other areas for possible modification are discussed here.

It’s not surprising that the editors maintain the paradigm in the end. Would they, of all people, take decades and even centuries of thinking and toss it overboard? Unlikely. They do show, nevertheless, a refreshing openness to consider that conventional wisdom about sequence stratigraphy could need major repairs if not a complete overhaul.

Science is about a progression of ideas, methods, and data, and even well-established paradigms change, sometimes through evolution, and sometimes through rapid revolution. Given this, it seems highly unlikely that sequence stratigraphy will stay as it is. More likely is that it will evolve and change as our knowledge and understanding grows, particularly through new methods that lead to new data and new understanding. Read Madof et al. (2016) with this in mind.

If Kuhn is right, though, their bets on evolution instead of revolution are based on hunches. And even evolutionary change can lead to radical revisions, given enough time.

Incidentally, Science Magazine reviewed a new book about Kuhn’s thesis 50 years after its debut (actually, 54 years). “Kuhn’s book, like the scientific revolutions it documents, initiated a paradigm shift in the way we think about scientific practice,” reviewer Sandra D. Mitchell writes, pointing out its enduring legacy. “Rather than seeing scientific change solely as rational progress—a slow climb up the mountain of truth—we now view it as a socially produced, psychologically influenced, and somewhat disjointed change of explanatory frameworks.”

We invite creation geologists to read these two papers and comment. How drastic a change does the Madof paper represent? Are there implications for interpreting the ages of strata?