Pozzuoli's Pillars Revisited

Natural History, May, 1999 by Stephen Jay Gould

   The preceding remarks are proposed entirely as speculations, whose chief
   use is to show that we are not entirely without principles from which we
   may reason on the physical structure of the moon, and that the volcanic
   theory is not the only one by which the phenomena could be explained.

But later discoveries only underscore the irony of what may be the greatest overextension of uniformitarian preferences ever proposed by a major scientist. Babbage suggested that lunar craters might be coral atolls because he wished to confute their catastrophic interpretation as volcanic vents and mountains. Indeed, lunar craters are not volcanoes. They are formed by the even more sudden and catastrophic mechanism of meteoritic impact!

Comprehensive worldviews like uniformitarianism or catastrophism provide both joys and sorrows to their scientific supporters: the great benefits of a guide to reasoning and observation, a potential beacon through the tangled complexities and fragmentary character of nature's historical records--ineluctably combined, however, with the inevitable, ever present danger of biases and false assurances that can blind us to contrary phenomena standing right before our unseeing eyes. Lyell himself emphasized this crucial point, with his characteristic literary flair, in the closing paragraph to his discussion of the pillars of Pozzuoli--in this case, to combat the prejudice that landmasses must be rock stable, with all changes of level ascribed to movements of the sea:

   A false theory it is well known may render us blind to facts, which are
   opposed to our prepossessions, or may conceal from us their true import
   when we behold them. But it is time that the geologist should in some
   degree overcome those first and natural impressions which induced the poets
   of old to select the rock as the emblem of firmness--the sea as the image
   of inconstancy.

But we also know that no good deed goes unpunished and that any fine principle can turn around and bite you in the ass. Lyell had used this maxim about the power of false theories to note that conventional preferences for catastrophism had been erroneously nurtured by the differential preservation of such evidence in our imperfect geological records. But Georges Cuvier--Lyell's French colleague, geology's leading catastrophist, and perhaps the only contemporary who could match Lyell's literary and persuasive skills--had issued the ultimate touche in a central passage of the most celebrated defense for geological catastrophism: his Discours preliminaire of 1812.

Here, Cuvier urges an opposite conclusion from the same valid argument about the blinding force of ordinary presuppositions. We are misled, Lyell had remarked, by the differential preservation of catastrophes in the geological record. Cuvier held, au contraire, that we become equally blinded by the humdrum character of daily experience. Most moments, Cuvier argues, feature no local wars or deaths and certainly no global cataclysms. So we do not properly credit these potential forces as agents of history, even though one global paroxysm every few million years (and therefore rarely, if ever, observable in a human lifetime) can shape the pageant of life on earth. Cuvier writes: