No one ought to feel surprise at much remaining as yet unexplained in regard to the origin of species and varieties, if he make due allowance for our profound ignorance in regard to the mutual relations of the many beings which live around us. Who can explain why one species ranges widely and is very numerous, and why another allied species has a narrow range and is rare? Yet these relations are of the highest importance, for they determine the present welfare, and, as I believe, the future success and modification of every inhabitant of this world. Still less do we know of the mutual relations of the innumerable inhabitants of the world during the many past geological epochs in its history. Although much remains obscure, and will long remain obscure, I can entertain no doubt, after the most deliberate study and dispassionate judgment of which I am capable, that the view which most naturalists until recently entertained, and which I formerly entertained—namely, that each species has been independently created—is erroneous. I am fully convinced that species are not immutable; but that those belonging to what are called the same genera are lineal descendants of some other and generally extinct species, in the same manner as the acknowledged varieties of any one species are the descendants of that species. Furthermore, I am convinced that Natural Selection has been the most important, but not the exclusive, means of modification.
That final paragraph to his Introduction is, in many ways, an excellent summary of evolutionary thought. Darwin here explains that there is much that we do not understand about the origin of species, but what is plainly obvious is that the species were not independently created and immutable.
Darwin lays before the reader the contrast that has been running through this genre of thought for centuries. There is much we cannot explain, but this we know. We may not know how it happened, but we know how it didn't happen.
It could have been written 150 years earlier by Leibniz who couldn't explain the solar system design very well, but he knew how it wasn't designed. And it could have been written today by an evolutionist such as Francis Collins who, like Darwin, cannot explain how biology's marvels arose, but he knows how they didn't arise.
The uncertainty that science leaves us with is, by now, not too surprising. Yes we make great progress. But for every answer there seem to be two new questions. It is hardly a revelation that science has not yet revealed all.
What is more of a revelation is the certainty part of the equation. Yes there is much we don't understand, and we have all heard that before. But listen to the evolutionist's pronouncement of certainty in the face of such unknowns. This is astonishing.
How is it that they, with no more scientific knowledge than the rest of us, can suddenly find such truth?
The answer, of course, is that to evolutionists the world does not look designed. God would never have created this mess, so therefore it must have evolved, somehow. The paragraph, as with the book (and legacy) that follow, reveals ignorance followed by metaphysical certainty. We don't know how evolution occurred, but we know this world was not designed so evolution must have occurred.
Such metaphysical certainty trumps all manner of scientific problems. What we do understand from science does not bode well for evolution and common descent, but so what? Such ideas face tremendous scientific barriers, but they are puny compared to the overwhelming certainty that they are true. This much we know.