It was a revolutionary new theory in biology that most transformed thought, and thus action. In 1859 there was published in London Charles Darwin’s On the Origin of Species by Means of Natural Selection. It rested in the study of natural history, the long record of the hundreds of thousands of years of organic life on earth.
Already well established by geologists and paleontologists, this record told of the rise, the development, and sometimes the disappearance of thousands of different forms of plant and animal organisms, or species. The record appeared to contradict the biblical book of Genesis, which described all forms of life as having been made by a Creator in the space of a single week about six thousand years ago.
Darwin (1809-1882) found one clue to the past in Malthus’s Essay on Population, which maintained that organisms tended to multiply to a point where there was not sufficient food for them all. In the intense competition for food, some of these organisms did not get enough and died. This was the struggle for existence. Darwin next asked himself what determined that certain individuals would survive and that others would die. Obviously, the surviving ones got more food, better shelter, better living conditions of all sorts.
If they were all identical organisms, then the only explanation would have to be some accidental variation in the environment. But it was clear from observation that individual organisms of a given species are not identical. Variations appear even at birth. Thus in a single litter of pigs there may be sturdy, aggressive piglets and also a runt, who is likely to get shoved aside in suckling and starve. In the struggle for existence, the runt is proved “unfit.”
This was the second of Darwin’s key phrases—the survival of the fittest. The organism best endowed to get food and shelter lives to procreate young that will tend to inherit these favorable variations. The variations may be slight indeed, but over generations they are cumulative; finally an organism is produced that is so different from the long-distant ancestor that it can be considered to be a new species. This new species has evolved by the working of natural selection. Plant and animal breeders had long made use of this process and had even directed it by breeding only the most desirable strains.
Darwin held that the variations in individuals of the same species at birth are accidental and that they are generally transmitted through inheritance. Darwin’s theory was later modified as scientists concluded that the important variations in the evolutionary process were not so much the numerous tiny ones Darwin emphasized but rather bigger and much rarer ones known as mutations.
The actual mechanism of heredity we know much better than Darwin did, thanks to the Austrian priest Gregor Mendel (1822-1884), whose experiments with crossbreeding garden peas laid the scientific basis of modern genetics and its study of genes and chromosomes.
The Origin of Species became a best seller, reviewed all over the world. The major reason for this attention was almost certainly the challenge that orthodox Christians felt they found in the book. Darwin received such wide attention because he seemed to provide for the secularist a process (evolution) and a causal agent (natural selection), where before there had been only vague “materialistic” notions that emphasized accident rather than order.
He also seemed to have struck a final blow against the argument, still very popular in Victorian times, that the organic world was full of evidence of God, the great designer. Finally, Darwin gained notoriety because of the frequent, though quite wrong, accusation that he made the monkey the brother of man. Later, in The Descent of Man (1871), Darwin carefully argued that Homo sapiens was descended not from any existing ape or monkey but from a very remote common primate ancestor.
The Origin of Species stirred up a most heated theological controversy. Fundamentalists, both Protestant and Catholic, damned Darwin and much of science itself. But the Catholic church and many Protestant bodies eventually viewed Darwinism as a scientific biological hypothesis, neither necessarily correct nor necessarily incorrect.
Most Christians tacitly accepted sufficient modification of Genesis to accommodate the scientist’s time scale, and they adjusted the classic theological arguments to propose a God who worked through organic evolution.
Moreover, it was quite clear to reflective individuals that nothing any scientist could produce could give the ultimate answers to the kind of problems set by the existence of God; it was quite clear to them that just as God’s eye is on the sparrow, it must once have also been on the dinosaur.