From it Lincoln learned geology and comparative biology. In it he found not only studies of the rocks, but also of the prenatal life of man, as related in its successive stages to corresponding types in the geological world. It was, in a word, an introduction to Darwin, which appeared many years later.
That many ministers denounced it as contradictory to the Bible we know, and the author anticipated this, nor is this a matter which gives us present concern. Some ministers believed it, and others, still unconvinced, read it with an open mind and waited for more light.
The important thing for us to know and clearly recognize is that in this book Abraham Lincoln not only learned what Herndon considers, and we are justified in considering, the essential theory of evolution, but he learned that such a view of creation is consistent with faith in God and the Bible.
We shall not find it possible to overestimate the importance of this discovery. Abraham Lincoln wrought out his philosophy of creation, his scheme of cause and effect, his theory of the processes of nature and life, under influences not atheistic nor hostile to religion, but distinctly favorable to it. He learned of evolution, and was convinced of its truth, from a book whose spirit and purpose was to present the view in harmony with the Christian faith.
The second, and subsequent editions, of Vestiges were "Greatly Amended by the Author," as the title page gave notice, and the changes were partly to incorporate new scientific data, but more to make clear the fact that the author's theory did not remove God from his universe, as some critics had asserted, but like Butler's Analogy had shown that God is in His world, working through the processes of nature. In 1846 appeared Explanations: A Sequel to Vestiges of the Natural History of Creation, a thin volume added to carry still further this double purpose, and doing it with marked success. The sixth edition combined the two in one volume.
It is interesting to learn that Lincoln, having read the first edition, later procured and read the sixth, in which the religious spirit of the author was made still more apparent.
This was the book which gave to Lincoln his theory of creation, of "miracles under law," and with one divine mind and purpose working through it all. Lincoln read little of natural science and cared practically nothing for philosophy, but he found in this book what he needed of both; and he found them in a system whose soul and center was the will of a righteous God.