It is important that these points should be clearly before our minds, because there has been current of late among naturalists a loose way of writing with reference to them, which seems to have imposed on many who are not naturalists. It has been said, for example, that such an organism as Eozoon may include potentially all the structures and functions of the higher animals, and that it is possible that we might be able to infer or calculate all these with as much certainty as we can calculate an eclipse or any other physical phenomenon. Now, there is not only no foundation in fact for these assertions, but it is from our present standpoint not conceivable that they can ever be realized. The laws of inorganic matter give no data whence any à priori deductions or calculations could be made as to the structure and vital forces of the plant. The plant gives no data from which we can calculate the functions of the animal. The Protozoon gives no data from which we can calculate the specialties of the Mollusc, the Articulate, or the Vertebrate. Nor unhappily do the present conditions of life of themselves give us any sure grounds for predicting the new creations that may be in store for our old planet. Those who think to build a philosophy and even a religion on such data are mere dreamers, and have no scientific basis for their dogmas. They are more blind guides than our primeval Protozoon himself would be, in matters whose real solution lies in the harmony of our own higher and immaterial nature with the Being who is the author of all life—the Father "from whom every family in heaven and earth is named."
SOME GENERAL CONCLUSIONS
XI
SOME GENERAL CONCLUSIONS
I
IT may very properly be said that many elements of uncertainty accompany the questions discussed in the previous chapters, and that in any case our information is too scanty to warrant any positive conclusions respecting the origin and earliest history of living beings. On the other hand, it is well to take stock of what we do know, and even of what we may reasonably suppose; keeping always in view the fact that some parts of the problem of the origin of life are at present insoluble, and may possibly ever continue in that condition. I may, therefore, profitably close with a summary of what at present seem to be ultimate facts and principles in this matter, which, if we have not yet fully attained to, we may at least keep in view as objective points.
If we admit that Eozoon was an animal, we may either assume that it was the first introduced on the earth, or that there were earlier and possibly even simpler creatures. In either case we begin the chain of animal life with a Protozoan belonging to one of the simpler or more generalized types of that group, and entitled to the name, both because of its place in order of time and of rank in the development of the animal kingdom. If we deny the claims of Eozoon, then the base of our animal system must for the present be found in the Sponges, Worms, Foraminifera, and Radiolarians of the Huronian, with the problematical laminated forms allied to Cryptozoon which seem to occur even in the Upper Laurentian. Thus in this case the miracle of creation stands before us in a somewhat more complex form, though greatly less so than if we had to accept the fauna of the Lower Cambrian as the oldest known.
Under any supposition we cannot hope to get beyond a Protozoan or a few Protozoa, and we must assume that these could perform perfectly in their simple way those functions of assimilation, organic growth, reproduction, sensation, and spontaneous motion, which are characteristic of these lowest forms of life in the present world.
It is plain, finally, that however simple we imagine this first possessor of animal life to be, we can have no scientific evidence of its origination either as an embryo or as an adult. If it had no living ancestors, we are thus face to face with the problem of the origin of animal life, either by what has been termed "Abiogenesis" of a merely physical and fortuitous kind, or by creation. This implies the previous production of the complex organic compound known as "Protoplasm," which can, so far as we know, be produced only through the agency of previously living "Protoplasm" formed by living plants. We have, therefore, to presuppose the "Abiogenesis" or creation of plants as predecessors of the animal; but here the same difficulty meets us. We have next to imagine the spontaneous origin of the structures of the "Protozoon"—its outer and inner substance, its nucleus, its pulsating vesicle, and its pseudopods, with its protective test, and its endowment with vital powers of locomotion, sensation, assimilation, nutrition, and reproduction. Can we suppose that all this could come of the chance interaction of physical causes?
At present the production of the living from the non-living seems to be an impossibility, and the suggestion that at some vastly distant point of past time physical conditions may have been so different from those at present existing as to permit spontaneous generation is of no scientific value. But if the existence of one primitive Protozoon be granted, what reason have we to believe that it contains potentially the germ of all the succeeding creatures in the great chain of life, and the power of co-ordinating these with the successive physical changes of the geological ages, and so producing the vast and complicated system of the animal kingdom, extending up to the present time? In doing so, we either elevate a low form of animal life into the role of Creator, or fall back on indefinite chance, with infinite probabilities against us. Reason, in short, requires us to believe in a First Cause, self-existent, omnipotent and all-wise, designing from the first a great and homogeneous plan, of which as yet but little has been discovered by us. Thus any rational scheme of development of the earth's population in geological time must be, not an agnostic evolution, but a reverent inquiry into the mode by which it pleased the Creator to proceed in His great work.