Here is a problem exactly similar. On examination we find that a certain house is built on a foundation of well-cemented concrete three feet deep, that it has ten courses of stone in the basement, forty courses of brick in the first story, thirty-six courses in the second, thirty-two in the third; with a roof of nine inch rafters, covered with inch boards, and an inch and a half layer of coal-tar and gravel; now tell us how long was the house in building? Why the very school-boy would laugh at the absurdity of such a question. He would say, "How can I tell unless I know where the materials were obtained, how they were conveyed, how many workmen were employed, and how much they could do in a day? If the rock had been brought from a distance, the brick to be made by hand, the lumber all dressed with a handsaw and jackplane, and all the work done by a slowgoing jobbing contractor who employed only three or four men—why, they would not get through in a year. But if the rock was found in excavating the cellar, if the brick were made by machinery and near at hand, the lumber dressed by steam saw and planing mills, and thirty or forty workmen employed, it might be all finished in a month."
So the geologist ought to say, "I do not know either the source of the materials of the earth's strata nor the distance from which they were conveyed to their present position, nor the forces which were employed in changing them from their primitive elements to the forms in which we now see them; therefore I cannot tell the time required for their formation. If the crust of the earth was originally fused into granite by intense heat, and this granite has been thrown up into vast mountains by the internal heat of the earth; and in turn, these mountains have been slowly worn away, by the action of wind, rain and frost, and conveyed down to the shores of the primeval ocean, by the still slower agency of mountain torrents and rivers; and if these deposits having first been the home of various species of animals and plants have hardened into rock which in turn has been heaved up by volcanic forces—if this was the mode of creation, hundreds of millions of years may have been required to produce the effects we now see upon the surface of the globe.
"But if the crust of the earth originally consisted of the various elements of which granite and other rocks are composed, if (as is generally conceded, granite is the lowest in the scale of all the rocks with which man is acquainted,) the granite was fused into its present condition by the intense heat generated by the chemical action of these elements upon each other, and if the overlying strata were consolidated by the vast pressure of a universal ocean, as is generally conceded to have covered the earth at a certain geologic period, and if these rocks were baked by their own chemical heat or by the continuous heat of the underlying granite, while the cooler temperature of the water above prevented the upper strata from becoming so solid—then, under such circumstances, a very few centuries might suffice." (See Lyell's Principles of Geology, chapters 12 and 32.)
Until these indispensable preliminaries are settled, geology can make no calculations of the length of time occupied by the formation of the strata.
Again, all geological computations of time are made upon the supposition that only the same agents were then at work which we now see, that they wrought with the same degree of force and produced the same results though working under widely different conditions. For example, suppose it now takes a year to deposit mud enough at the bottom of the sea, to make an inch of rocks, and if mud was deposited no faster in those remote ages, then the rocks would be as old as there are inches in the eight or nine miles depth to which the strata extends. But how can we prove that mud was deposited at the same rate then as now? And so the whole fabric of geological chronology vanishes into a mere unproved notion, based upon an if.
It is truly astonishing that any sober-minded person should allow himself to be shaken in his religious convictions by the alleged results of a science so unformed and imperfect, as geologists themselves acknowledge their favorite science to be. Thus Hugh Miller admits, "There are no calculations more doubtful than those of the geologist;" and again, "It furnishes us with no certain clue by which to unravel the unapproachable mysteries of creation." (See Footprints of the Creator, page 313.)
These mysteries belong to the wondrous Creator, and to Him only. Men attempt to theorize upon them, and to reduce them to law; but all nature rises up against them in their presumptuous rebellion. A stray splinter of cone-bearing wood, a fish's skull, the skeleton of a reptile, the tooth or jaw of a quadruped, all or any of these things— weak and insignificant as they may seem—when found imbedded in the strata of the rocks, become evidence too strong for man and all his theories. These puny fragments in the grasp of truth become weapons as irresistible as the dry bone in the hand of Sampson of old; and our slaughtered theories lie piled up heaps upon heaps before them.
Then, again, they are quarreling about the leading principles of the science. Hopkins attempts to prove that the crust of the earth is eight hundred miles thick, while Humboldt asserts that it is less than twenty-four. As the temperature increases one degree for every forty-five feet we descend into the earth, so, at that rate, in less than twenty-four miles the heat would be so great as to melt iron and almost any known substance. But here, again, they differ. Wedgewood declares that iron melts at 21,000 degrees Fahrenheit; while Professor Daniels is positive that it melts at 2,786 degrees, Fahrenheit. Only a slight difference of 18,214 degrees.
But then comes the great question: if granite is the lowest layer in the strata, what is below the granite? De Beaumont affirms that "the whole globe, with the exception of a thin envelope—much thinner in proportion than the shell of an egg—is a melted mass kept fluid by heat, but constantly cooling and contracting its dimensions and occasionally cracking and falling in, and squeezing upwards large portions of the mass, thus producing those folds or wrinkles which we call mountain chains." On the other hand, Davy and Lyell think that "we may perhaps refer the heat of the interior to chemical changes going on in the earth's crust." So much for the uncertainties of geology.
If space permitted, it would be easy to go over other sciences and show similar uncertainties in them all. It is worthy of notice that the uncertainties of science increase just in proportion to our interest in it. About what does not concern us, it is very positive; but very uncertain about our dearest interests. The astronomer may calculate with considerable certainty the movements of distant planets with which we have no intercourse; but he cannot predict the heat or cold, clouds or sunshine, and other phenomena continually occurring on our earth. The forces of heat may be measured, to some extent, but what physician can measure the strength of the malignant fever that is destroying the life of his patient. The chemist can thoroughly analyze any foreign substance, but the disease of his own body, which is bringing him to the grave, he can neither weigh, measure nor remove. Science is very positive about distant stars and remote ages, but stammers and hesitates about the very lives of its professors.