But how apply all this to the Geology of the Old Red Sandstone? Very directly. The ichthyolites of this ancient formation hold, as has been said, an intermediate place, unoccupied among present existences, between the two series, and in some respects resemble the osseous, and in some the cartilaginous tribes. The fact reminds one of Dr. Johnson's shrewd objection to the theory embraced by Soame Jenyns in his Free Inquiry, and which was the theory also of Pope and Bolingbroke. The metaphysician held, with the poet and his friend, that there exists a vast and finely graduated chain of being from Infinity to nonentity—from God to nothing; and that to strike out a single link would be to mar the perfection of the whole.[Q] The moralist demonstrated, on the contrary, that this chain, in the very nature of things, must be incomplete at both ends—that between that which does, and that which does not exist, there must be an infinite difference—that the chain, therefore, cannot lay hold on nothing. He showed, further, that between the greatest of finite existences and the adorable Infinite there must exist another illimitable void—that the boundless and the bounded are as widely separated in their natures and qualities as the existent and the non-existent—that the chain, in short, cannot lay hold on Deity. He asserted, however, that not only is it thus incomplete at both ends, but that we must regard it as well nigh as incomplete in many of its intermediate links as at its terminal ones; that it is already a broken chain, seeing that between its various classes of existence myriads of intermediate existences might be introduced, by graduating more minutely what must necessarily be capable of infinite gradation; and that, to base an infidel theory on the supposed completeness of what is demonstrably incomplete, and on the impossibility of a gap existing in what is already filled with gaps, is just to base one absurdity on another.[R] Now, we find the Geology of what may be termed the second age of vertebrated existence (for the Lower Old Red Sandstone was such) coming curiously in to confirm the reasonings of Johnson. It shows us the greater part of the fish of an entire creation thus insinuated between two of the links of our own.
"See, through this air, this ocean, and this earth,
All matter quick, and bursting into birth;
Above, how high progressive life may go!
Around, how wide! how deep extend below!
Vast chain of being! which from God began—
Nature's ethereal, human angel, man,
Beast, bird, fish, insect—what no eye can see,
No glass can reach; from Infinite to thee—
From thee to nothing. On superior powers
Were we to press, inferior might on ours;
Or in the full creation leave a void,
Where, one step broken, the great scale's destroyed:
From Nature's chain, whatever link you strike,
Tenth, or ten thousandth, breaks the chain alike."
Essay on Man.
[R] The following are the well-stated reasonings of Dr. Johnson, a writer who never did injustice to an argument for want of words to express it in:—
"The scale of existence from Infinity to nothing cannot possibly have being. The highest being not infinite must be at an infinite distance from Infinity. Cheyne, who, with the desire inherent in mathematicians to reduce every thing to mathematical images, considers all existence as a cone, allows that the basis is at an infinite distance from the body, and in this distance between finite and infinite there will be room forever for an infinite series of indefinable existence.
"Between the lowest positive existence and nothing, whenever we suppose positive existence to cease, is another chasm infinitely deep, where there is room again for endless orders of subordinate nature, continued forever and ever, and yet infinitely superior to nonexistence.
"To these meditations humanity is unequal. But yet we may ask, not of our Maker, but of each other, since on the one side creation, whenever it stops, must stop infinitely below infinity, and on the other infinitely above nothing, what necessity there is that it should proceed so far either way—that being so high or so low should ever have existed. We may ask, but I believe no created wisdom can give an adequate answer.
"Nor is this all. In the scale, wherever it begins or ends, are infinite vacuities. At whatever distance we suppose the next order of beings to be above man, there is room for an intermediate order of beings between them; and if for one order, then for infinite orders, since every thing that admits of more or less, and consequently all the parts of that which admits them, may be infinitely divided; so that, as far as we can judge, there may be room in the vacuity between any two steps of the scale, or between any two points of the cone of being, for infinite exertion of infinite power."—Review of "A Free Inquiry."