The Problem of Species

a) Terms of the Problem — b) First Origin of Life — c) Origin of Species

a) Terms of the Problem

We find on earth the wondrous thing called life. We see life manifested in living bodies. We notice a great multiplicity and variety of living bodies. We know that many types of living bodies existed in earlier ages which are no longer found among us, and that many types now found on earth were not found in earlier times. These facts confront us with a twofold problem: How did life originate? and How did the enormous variety of species come to be? These are the terms of the problem.

b) First Origin of Life

How did life originate on earth? Two possible answers present themselves: either life always existed on earth (or was communicated to it from some other living world), or life came into existence at some point in the past history of the earth. Most scientists and all philosophers accept the second alternative: life had a beginning on earth. How did this beginning come about?

Two general types of answer are again possible: either life arose from non-living matter by purely natural processes — this theory is called spontaneous generation — or life was introduced into the material world by some agency that transcends material nature, that is, by a creative act of God.

Spontaneous generation is the supposed arising of living from non-living matter by a natural process, without the agency of parent organisms. It is to be carefully distinguished from what may be called equivocal generation — the arising of living organisms from the products of already-living organisms, or from already-living organisms of a different kind. Flies maggots arising from rotting flesh were once thought to be instances of spontaneous generation; but it has been established that they arise from eggs deposited in the flesh by the parent flies. All such supposed instances of spontaneous generation have, upon investigation, proved to be cases of ordinary equivocal or univocal generation.

Spontaneous generation in the strict sense — the arising of a genuinely living organism from purely non-living matter by natural process — is philosophically impossible. We have seen that life is essentially different from non-life; that living bodies differ essentially from lifeless bodies. Now, from what is essentially non-living, life — something essentially different — cannot arise by any natural process. For a natural process is the unfolding of what is already latent or potential in a thing; and the essentially non-living, as such, has no potentiality for life. Spontaneous generation we have found inadequate to explain the origin of life, and indeed we have seen that it is impossible.

The origin of the first life on earth must therefore be traced to the creative act of God. Life was introduced into the material world by divine agency — not by any spontaneous natural process.

c) Origin of Species

Given that life was introduced by divine creation, how did the enormous variety of species come to be? Two broad families of theory present themselves: theories of changeless species and theories of transformed or derived species.

Theories of Changeless Species. Three forms of this view have been advanced. (i) Independent successive creations: God created all species separately, calling each into existence by a distinct creative act. This has been the common view among biologists and philosophers up to recent times, and it remains a fully defensible position. (ii) Seed-essences (spermatikoi logoi): God infused into matter at the beginning seed-powers or rationes seminales which, in the course of time, developed into the various species of organisms. This view, associated with Augustine and Aquinas, holds that only the potentialities were created at the beginning, and that the species unfolded from these over time — a view entirely compatible with a long geological history. (iii) Essences modified by a specially communicated power: God created a few original types and endowed matter with a special communicated power to develop these into the many species we now observe.

Theories of Transformed or Derived Species (Evolution). These theories hold that the presently existing species have descended by natural processes of transformation from earlier and simpler ancestors. Several forms exist.

Haeckelian evolution or monistic evolution holds that matter itself, by its own intrinsic and necessary forces, without any guidance from without, developed from an original chaos into all the forms of living and non-living things we now observe. This theory is to be rejected outright. First, it requires us to accept self-produced or uncaused matter as the ultimate reality; but self-produced or uncaused matter is not a possible being, for whatever exists either exists of itself necessarily (and is therefore God, not matter) or it is produced by another. A world-stuff that has always existed is simply an uncaused being — which is precisely what we mean by God; but the hylozoist’s world-stuff is contingent being and therefore cannot explain its own existence, nor can it explain the fact that material bodies possess organic life. Secondly, this type of monism leaves us to suppose that the orderly universe came to its present state and condition by pure chance. No one who observes the great cosmic movements or who looks at the delicate order and balance of the tiniest organism can accept such a suggestion for a moment. Thirdly, Haeckel’s monism proposes uncaused mechanical motion as the source of all things — but motion without a mover is a philosophical contradiction.

Darwinian evolution, or the evolution of natural selection, teaches that species have developed from earlier species by the accumulation of chance variations, those individuals surviving whose variations happen to be useful in the struggle for existence, and thus propagating their useful variations. Natural selection is, at best, a principle of elimination — it explains why some types die out; it does not explain how new types arise. The appearance of a new specific nature — something essentially new — cannot be accounted for by the mere accumulation of accidental variations upon a pre-existing nature. The evolutionary process, as Darwin describes it, offers no explanation of the origin of the essences which natural selection selects; it assumes them as already given. Furthermore, the known facts of heredity and genetics, far from supporting the unlimited plasticity of species which Darwinian theory requires, tend rather to confirm the stability of specific types within the range of variation characteristic of the species.

Christian evolution holds that God created the primary organisms, and endowed matter with directed potencies or powers — whether ordinary natural potencies or specially communicated ones — to develop from those primary organisms into all the species we now observe, under the general governance of divine Providence. This position is philosophically possible. It does not contradict any defined doctrine of faith (provided the special creation and infusion of the human soul is maintained). It is compatible with the geological evidence of a long history of organic life and with the observable succession of forms in the fossil record. But it is as yet an unproved hypothesis; the evidence is suggestive but not conclusive.

Let us now round out our position on this subject of evolution by a series of questions and answers:

Is it possible for a Christian to accept evolution as the explanation of the origin of species, if man is excluded from the evolutionary scheme?—Yes.

Is not evolution already utterly condemned in the condemnation of the Haeckelian and Darwinian systems?—No; two special theories on the manner in which evolution is supposed to carry on have been rejected; evolution as a possible fact has not been denied.

Is evolution, excluding man, really a fact?—It has not been proved so, even for the lowest of organisms. It seems probable enough. It may well be a fact. Again, it may not. We await further evidence for one conclusion or the other.

Are not all scientists avowed champions of the evolutionary theory or hypothesis?—No, but many are. Yet it is not the function of a scientist to champion any cause or to promote any enthusiasm; his work is to discover the facts in the field which he investigates. What any scientist believes is of small importance for science; true science, as Ruskin says, “does not speak until it knows,” and can establish knowledge by inescapable proof.

Summary of the Article

In this Article we have faced the problem of the origin of life and of the variety of species. Spontaneous generation we have found inadequate to explain the origin of life, and indeed we have seen that it is impossible. We have reduced to two general classes the systems which attempt to explain the origin of species: the theory of changeless species, and the theory of transformed or derived species. Under the first head, we have discussed the theories of independent successive creations, of seed-essences, of essences changed by a specially communicated power for specific modification. Under the second head, we have grouped the evolutionary theories, and have discovered that Haeckelian evolution (or monistic evolution) and Darwinian evolution (or the evolution of natural selection) fail to square with reason, with facts, with experience, and are therefore to be rejected as false doctrine. We have explained Christian evolution and have admitted its possibility, although we are forced to acknowledge that it is an unproved hypothesis.