The Belief in Creation

Species have changed, and are still slowly changing by the preservation and accumulation of successive slight favourable variations.

Why have all the most eminent living naturalists and geologists rejected this view of the mutability of species?

It cannot be asserted that organic beings in a state of nature are subject to no variation;

it cannot be proved that the amount of variation in the course of long ages is a limited quantity;

no clear distinction has been, or can be, drawn between species and well-marked varieties. It cannot be maintained that species when intercrossed are invariably sterile, and varieties invariably fertile; or that sterility is a special endowment and sign of creation.

The belief that species were immutable productions was almost unavoidable as long as the history of the world was thought to be of short duration;

Now that we have acquired some idea of the lapse of time, we are too apt to assume, without proof, that the geological record is so perfect that it would have afforded us plain evidence of the mutation of species, if they had undergone mutation.

But the chief cause of our natural unwillingness to admit that one species has given birth to other and distinct species, is that we are always slow in admitting any great change of which we do not see the intermediate steps.

The difficulty is the same as that felt by so many geologists, when Lyell first insisted that long lines of inland cliffs had been formed, and great valleys excavated, by the slow action of the coast-waves.

The mind is unable to grasp the full meaning of 100,000,000 years.

It cannot add up and perceive the full effects of many slight variations, accumulated during an almost infinite number of generations.

We hide our ignorance under such expressions as the ‘plan of creation,’ ‘unity of design,’ &c.

We think that we give an explanation when we only restate a fact.

Those who believe that species are mutable should express their belief so that the prejudice against this idea can be removed.

Several eminent naturalists believe that:

• many reputed species in each genus have evolved [are not real species]
• other species are real [independently created].

This seems to me a strange conclusion to arrive at.

They admit that a multitude of forms, which till lately they themselves thought were special creations, and which are still thus looked at by the majority of naturalists, and which consequently have every external characteristic feature of true species.

They admit that these have been produced by variation, but they refuse to extend the same view to other and very slightly different forms.

Nevertheless they do not pretend that they can define, or even conjecture, which are the created forms of life, and which are those produced by secondary laws.

They admit variation as a vera causa in one case. But they arbitrarily reject it in another case, without assigning any distinction in the two cases.

Do they really believe that certain elemental atoms have been commanded suddenly to flash into living tissues?

How far do I extend the doctrine of the modification of species?

The more distinct the forms we consider, the more our arguments fall away in force.

But some arguments of the greatest weight extend very far. All the members of whole classes can be connected together by chains of affinities, and all can be classified on the same principle, in groups subordinate to groups.

Fossil remains sometimes tend to fill up very wide intervals between existing orders.

Organs in a rudimentary condition plainly show that an early progenitor had the organ in a fully developed state; and this in some instances necessarily implies an enormous amount of modification in the descendants.

Throughout whole classes various structures are formed on the same pattern, and at an embryonic age the species closely resemble each other.

Therefore, the theory of descent with modification embraces all the members of the same class.

I believe that:

• animals have descended from at most only 4-5 progenitors.
• plants have descended from an equal or lesser number.

I believe that all animals and plants have descended from some one prototype.

All living things have much in common, in their:

• chemical composition
• germinal vesicles
• cellular structure
• laws of growth and reproduction.

This is seen in:

• the same poison often similarly affects plants and animals.
• the poison secreted by the gall-fly produces monstrous growths on the wild rose or oak-tree.

So probably all the organic beings on this earth have descended from some one primordial form, into which life was first breathed.

When the views entertained in this volume on the origin of species, or when analogous views are generally admitted, we can dimly foresee that there will be a considerable revolution in natural history.

Systematists will no longer be haunted by the doubt whether this or that form is a species.

This will end the endless disputes whether 50 species of British brambles are true species or not.

Systematists will have only to decide (not that this will be easy) whether any form is constant and distinct from other forms, to be capable of definition.

If definable, whether the differences be sufficiently important to deserve a specific name.

This latter point will become a far more essential consideration than it is at present; for differences, however slight, between any two forms, if not blended by intermediate gradations, are looked at by most naturalists as sufficient to raise both forms to the rank of species.

Hereafter, we shall be compelled to acknowledge that the only distinction between species and well-marked varieties is, that the latter are known, or believed, to be connected at the present day by intermediate gradations, whereas species were formerly thus connected.

Hence, without quite rejecting the consideration of the present existence of intermediate gradations between any two forms, we shall be led to weigh more carefully and to value higher the actual amount of difference between them.