The Uncertainty of Geological Science.
By A. T. J.
Archibald Geikie, LL.D., F.R.S., Professor of Geology, University of Edinburgh, spoken of by the New York Independent as “an author who is surpassed by none of his compeers in scientific attainment, and hardly equaled by any of them for his gifts in the imparting of knowledge,” is the author of a “Text Book of Geology;” and also the author of the treatise on geology in the latest edition of the “Encyclopedia Britannica;” therefore we shall doubtless be justified in accepting his work as the latest, the ablest, and the best contribution in favor of geological science as it is at the present day. After reading and studying it through three times, the impression left by it upon my mind is that expressed by the title which I have placed at the head of this article. In this discussion we propose no comparison of geology and the Bible. We intend to examine geological science on its own merits. We want to know upon what it rests. We want to know what its merits are. We want to know whether indeed it has any merit that would justify a comparison with the Bible. Geology is defined as “the science which investigates the history of the earth.” “Its object,” as stated, “is to trace the progress of our planet from the earliest beginning of its separate existence, through its various stages of growth, down to the present condition of things.” “It seeks to determine the manner in which the evolution of the earth’s great surface features has been effected.” But it is only by a proper understanding of the present order of things, that the past can be made out. He says: “Only in proportion as we understand the present, where everything is open on all sides to the fullest investigation, can we expect to decipher the past, where so much is obscure, imperfectly preserved, or not preserved at all. A study of the existing economy of nature ought thus to be the foundation of the geologist’s training.” So, then, here we have properly, at the very beginning, laid down the foundation of geological deduction. And we may, properly enough, inquire, Is this foundation secure? is it a foundation upon which we can firmly stand and safely build? Let Mr. Geikie answer. In the very next paragraph he says:— “While, however, the present condition of things is thus employed, we must obviously be on our guard against the danger of unconsciously assuming that the phase of nature’s operations which we now witness has been the same in all past time, that geological changes have taken place in former ages in the manner and on the scale which we behold to-day, and that at the present time all the great geological processes, which have produced changes in the past eras of the earth’s history, are still extant and active. Of course we may assume this uniformity of action, and use the assumption as a working hypothesis. But it ought not to be allowed any firmer footing, nor on any account be suffered to blind us to the obvious truth that the few centuries wherein man has been observing nature, form much too brief an interval by which to measure the intensity of geological action in all past time. For aught we can tell, the present is an era of quietude and slow change, compared with some of the eras which have preceded it. Nor can we be sure that, when we have explored every geological process now in progress, we have exhausted all the causes of change which even in comparatively recent times have been at work.” And in another place (No. 1, under the Age of the Earth) he says plainly that this assumption “may be entirely erroneous.” According to this, “the foundation of a geologist’s training” is an “assumption,” and this assumption must not be allowed a “firm footing” because it may blind us to an obvious truth, and because it also may be “entirely erroneous.” And here, after laying a—yes, the—foundation, he has as certainly destroyed it, and we might exclaim, not exactly with the psalmist, “If the foundations be destroyed, what shall the” geologists “do”? If, therefore, the foundation be assumption, the superstructure can be nothing more, and this also is just as plainly stated as is the foregoing, as follows:— “In dealing with the Geological Record, as the accessible solid part of the globe is called, we cannot too vividly realize that at the best it forms but an imperfect chronicle. Geological history cannot be compiled from a full and continuous series of documents. From the very nature of its origin, the record is necessarily fragmentary, and it has been further mutilated and obscured by the revolutions of successive ages.” “Enormous gaps occur where no record has been preserved at all. It is as if whole chapters and books were missing from an historical work.”—See Part V., Gaps in the Geological Record; also in the Introduction. But what degree of reliability could be placed in the deductions of one who should presume to give the exact course of events in a certain history, when “whole chapters and books were missing” from the only extant historical record of the events? None whatever. For it is entirely by conjecture that the events of the missing parts must be made up. This is particularly so of the geologists’ deductions, for, as we have seen, there are not only “whole chapters and books missing,” but they are not sure that they have the correct interpretation of those which remain. Therefore they guess at the course of events in that part of the record which remains, and then supply the missing parts by other guesses; and so it is a guess all around. Geology reveals no beginning:—
“It is still true that in the data with which they are accustomed to deal, as comprising the sum of geological evidence, there can be found no trace of a beginning. The oldest rocks which have been discovered on any part of the globe have probably been derived from other rocks older than themselves. Geology, by itself, has not yet revealed, and is little likely ever to reveal, a trace of the first solid crust of our globe. If, then, geological history is to be compiled from direct evidence furnished by the rocks of the earth, it cannot begin at the beginning of things, but must be content to date its first chapter from the earliest period of which any record has been preserved among the rocks.”—Part I., Cosmical Aspects. If, then, it begins at an uncertain place, and follows an uncertain course, and sometimes no course at all, how can the ending be anything else but uncertain? In Part II., Geognosy, he discusses the Age of the Earth, and Measures of Geological Time, from which we extract the following. He says that the age of the earth may be attacked from either the geological or the physical side. First the geological:— “The geological argument rests chiefly upon the observed rates at which geological changes are being effected at the present time, and is open to the obvious preliminary objection that it assumes the existing rate of change as the measure of past revolutions,—an assumption which may be entirely erroneous, for the present may be a period when all geological events march forward more slowly than they used to do.” “If we assume that the land has been worn away, and that stratified deposits have been laid down nearly at the same rate as at present, then we must admit that the stratified portion of the crust of the earth must represent a very vast period of time. Dr. Croll puts this period at not less, but much more, than sixty million years.” “On any supposition it must be admitted that these vicissitudes in the organic world can only have been effected with the lapse of vast periods of time, though no reliable standard seems to be available whereby these periods are to be measured. The argument from geological evidence is strongly in favor of an interval of probably not less than one hundred million years since the earliest form of life appeared upon the earth, and the oldest stratified rocks began to be laid down.” Yes, no doubt, “if we assume” that such and such is the case, “probably” the balance will follow. But why are we called upon to “assume” an “erroneous assumption” only for the purpose of reaching an indefinite conclusion? This “argument from geological evidence,” is like the famous essay on “Snakes in Ireland,” viz., “There are no snakes in Ireland.” So, likewise, there is no geological evidence, and he says so. Why may we not just as rightfully assume that these changes and revolutions have been wrought in short periods, or even suddenly? Many of them have certainly been made violently. A. T. J.