The historical wellspring of randomness in evolutionary theory is Darwin’s own insistence on “chance” at the causal foundations of life.
Given Lincoln’s acknowledgment of the evidence of design in nature, he would be banned from expressing his views on evolution in most public schools today.
It looks like Darwin was as impressed as everyone else by the amazing ingenuity in orchids and could not ignore the evidence for design.
A less class-bound kind of protectiveness was shown to Darwin in the United States by Professor Asa Gray of Harvard University.
Darwin was not at all unsure about the value of his orchid book. He viewed it as presenting the most convincing case for natural selection that he could make.