The Origin of One or Several Species
In 1859, naturalist Charles Darwin published a book titled On the Origin of Species. In doing so he brought together his own observations and the work of colleagues past and present to formulate a theory with far-reaching implications. Darwin's answer to the question of the origin of species is that current species are descended from ancestral ones through the process of natural selection. He shows convincingly that the forms of life on Earth have changed over time, and that they could be the modified descendants of earlier forms. However, I noticed when most of the way through Darwin's argument that in a book titled On the Origin of Species he had not even touched on the origin of life-- on how the first species had come into existence, or even whether there were one or several. When he briefly addressed this subject in the final chapter it was in a hesitant, contradictory way. I set out to determine exactly what Darwin had included about the origin of the first species, and why he had concluded so little.
I went through the last chapter to take a closer look at the contradictions. One of the few firm declarations that Darwin gives on the subject is “I believe that animals have descended from at most only four or five progenitors, and plants from an equal or lesser number,” (394) (emphasis mine). Clearly, however, the possibility that has captured his imagination is a different one. In speaking of the age of the Earth, he refers to “...the ages which have elapsed since the first creature, the progenitor of innumerable generations, was created,” (396-7). He makes no final statement to reconcile these two possibilities, or even to show which of the two he prefers and why.
Darwin has been arguing for several hundred pages against the view that God created all of the current species, but in the first quote above he admits a remarkably similar possibility-- that God created a certain number of original species, which then evolved into the many diverse forms found today. For evolution to have started from several points, instead of one, is not necessary to his theory. So why endorse this hypothesis?
Several pages later Darwin refers to the contradicting hypothesis of the “first creature,” the single species from which all others follow. When addressing this possibility too he uses the word “created” rather than a more neutral construction, never implying that life could have come into existence without a Creator. The question he sidesteps is whether God first created one form of life, or several, and has very little to do with current arguments over how life could have spontaneously evolved on Earth. Those arguments rose out of his theory much later.
This, for me, brought up two related questions about the Darwinian evolution expressed in On the Origin of the Species. Since Darwin himself always writes of the beginning of life as an act of God, why is the question of whether God created one form of life or several such a controversial one? And why doesn't Darwin clearly state his opinion on such an important point? Both of these questions interested me because they touched on the ambiguous role of God in this text and in the original theory of evolution.
Darwin concludes that within the system he has uncovered “...the production and extinction of the past and present inhabitants of the world should have been due to secondary causes,” (397). In other words, biological evolution does not require the repeated intervention of God, as did the current view of all species being separately created. The only act of God under this system occurs at the very beginning. This alone would guarantee that all Christians, whether or not they accepted the premise of evolution by natural selection, would feel very strongly about the creation of species and how exactly it occurred.
I believe that there is another potential for controversy as well-- one that Darwin does not address but that became very important in the later evolution of his theory. If life can be traced back to several separate original species, the implication is that those species could not have separately arisen by chance but must have been created. This further implies a Creator working in a particular pattern. If, however, all life arose from one extremely simple form, there is the possibility that this form was not deliberately “created” but came into existence through some fluke, some chemical accident. This larger question is one that Darwin himself never even hints at, but is extremely important to evolutionary biologists today and is one of the major points of conflict between some current theories of evolution and intelligent design, or creationism.
It is possible that Darwin did not definitively answer the question of (an) original species in order to avoid the arguments that would have been marshaled against him. There is no way, of course, to be completely certain, but I do not think that this was the reason-- or not the entire reason. The central premise of On the Origin of Species shows that Darwin had no difficulties tackling controversial questions, or providing groundbreaking answers to them. He argues determinedly to show that species have not always existed in the form that they now assume, but have changed immensely over the centuries and millennia. He defends the revolutionary concept of natural selection eloquently, laying out in detail the process by which he believes that species have evolved. In both of these cases he uses a multitude of facts as well as logical hypothetical cases to construct his arguments. In any discussion of the origin of life, on the other hand, he must rely upon conjecture.
The dearth of concrete evidence is, I believe, the real reason why Darwin did not argue that all life on Earth is descended from a common ancestor. In his last chapter, Darwin lists the many similarities found within each class of organism and concludes “Therefore I cannot doubt that the theory of descent with modification embraces all the members of the same class,” (394) This, he lets us know, is all he can say based on present-day evidence. On this basis he proposes the maximum number of original species. He then includes the possibility of a single original species because it accords better with his theory, but he will not give this hypothesis precedence without the requisite evidence. The lack of evidence speaking directly to the origin of species, and Darwin's refusal to speculate groundlessly, lead to the sparse and conflicted statements on this, his original subject of inquiry.
Darwin, Charles. On the Origin of Species. Ed. Joseph Carroll. Canada: Broadview Press, 2003.