To the many partial designs which Paley's Natural Theology points out, and which still remain what they were, the doctrine of Evolution adds the design of a perpetual progress. Things are so arranged that animals are perpetually better adapted to the life they have to live. The very phrase which we commonly use to sum up Darwin's teaching, the survival of the fittest, implies a perpetual diminution of pain and increase of enjoyment for all creatures that can feel. If they are fitter for their surroundings, most certainly they will find life easier to live. And, as if to mark still more plainly the beneficence of the whole work, the less developed creatures, as we have every reason to believe, are less sensible of pain and pleasure; so that enjoyment appears to grow with the capacity for enjoyment, and suffering diminishes as sensitivity to suffering increases. And there can be no doubt that this is in many ways the tendency of nature. Beasts of prey are diminishing; life is easier for man and easier for all animals that are under his care: many species of animals perish as man fills and subjugates the globe, but those that remain have far greater happiness in their lives. In fact, all the purposes which Paley traces in the formation of living creatures are not only fulfilled by what the Creator has done, but are better fulfilled from age to age. And though the progress may be exceedingly slow, the nature of the progress cannot be mistaken.
If the Natural Theology were now to be written, the stress of the argument would be put on a different place. Instead of insisting wholly or mainly on the wonderful adaptation of means to ends in the structure of living animals and plants, we should look rather to the original properties impressed on matter from the beginning, and on the beneficent consequences that have flowed from those properties. We should dwell on the peculiar properties that must be inherent in the molecules of the original elements to cause such results to follow from their action and reaction on one another. We should dwell on the part played in the Universe by the properties of oxygen, the great purifier, and one of the great heat-givers; of carbon, the chief light-giver and heat-giver; of water, the great solvent and the storehouse of heat; of the atmosphere and the vapours in it, the protector of the earth which it surrounds. We should trace the beneficent effects of pain and pleasure in their subservience to the purification of life. The marks of a purpose impressed from the first on all creation would be even more visible than ever before.
And we could not overlook the beauty of Nature and of all created things as part of that purpose coming in many cases out of that very survival of the fittest of which Darwin has spoken, and yet a distinct object in itself. For this beauty there is no need in the economy of nature whatever. The beauty of the starry heavens, which so impressed the mind of Kant that he put it by the side of the Moral Law as proving the existence of a Creator, is not wanted either for the evolution of the world or for the preservation of living creatures. Our enjoyment of it is a super-added gift certainly not necessary for the existence or the continuance of our species. The beauty of flowers, according to the teaching of the doctrine of Evolution, has generally grown out of the need which makes it good for plants to attract insects. The insects carry the pollen from flower to flower, and thus as it were mix the breed; and this produces the stronger plants which outlive the competition of the rest. The plants, therefore, which are most conspicuous gain an advantage by attracting insects most. That successive generations of flowers should thus show brighter and brighter colours is intelligible. But the beauty of flowers is far more than mere conspicuousness of colours even though that be the main ingredient. Why should the wonderful grace, and delicacy, and harmony of tint be added? Is all this mere chance? Is all this superfluity pervading the whole world and perpetually supplying to the highest of living creatures, and that too in a real proportion to his superiority, the most refined and elevating of pleasures, an accident without any purpose at all? If Evolution has produced the world such as we see and all its endless beauty, it has bestowed on our own dwelling-place in lavish abundance and in marvellous perfection that on which men spend their substance without stint, that which they value above all but downright necessities, that which they admire beyond all except the Law of Duty itself. We cannot think that this is not designed, nor that the Artist who produced it was blind to what was coming out of His work.
Once more, the doctrine of Evolution restores to the science of Nature the unity which we should expect in the creation of God. Paley's argument proved design, but included the possibility of many designers. Not one design, but many separate designs, all no doubt of the same character, but all worked out independently of one another, is the picture that he puts before us. But the doctrine of Evolution binds all existing things on earth into one. Every mineral, every plant, every animal has such properties that it benefits other things beside itself and derives benefit in turn. The insect developes the plant, and the plant the insect; the brute aids in the evolution of the man, and the man in that of the brute. All things are embraced in one great design beginning with the very creation. He who uses the doctrine of Evolution to prove that no intelligence planned the world, is undertaking the self-contradictory task of showing that a great machine has no purpose by tracing in detail the marvellous complexity of its parts, and the still more marvellous precision with which all work together to produce a common result.
To conclude, the doctrine of Evolution leaves the argument for an intelligent Creator and Governor of the world stronger than it was before. There is still as much as ever the proof of an intelligent purpose pervading all creation. The difference is that the execution of that purpose belongs more to the original act of creation, less to acts of government since. There is more divine foresight, there is less divine interposition; and whatever has been taken from the latter has been added to the former.
Some scientific students of Nature may fancy they can deduce in the working out of the theory results inconsistent with religious belief; and in a future Lecture these will have to be examined; and it is possible that the theory may be so presented as to be inconsistent with the teaching of Revelation. But whatever may be the relation of the doctrine of Evolution to Revelation, it cannot be said that this doctrine is antagonistic to Religion in its essence. The progress of Science in this direction will assuredly end in helping men to believe with more assurance than ever that the Lord by wisdom hath founded the earth, by understanding hath He established the heavens.