This, reasoned Darwin, would allow the evolution of the whole kingdom of nature from primeval beginnings, by the gradual process of evolution by natural selection. But Darwin had problems. This, Darwin reasoned, would tend to make every species somewhat uniform in character, in the same way that blending paint of different colours always ends up as a nondescript grey-brown sludge. Darwin never solved this problem, and a few years after his death, his ideas were in danger of becoming an outmoded footnote. One of the consequences of natural selection is its randomness.
Natural selection is blind to the past and the future, and works with the material available.
It does not work like a breeder of domestic animals or plants, with a defined end in view. But given Darwin's limited knowledge of the mechanisms of heredity, we may wonder whether Darwin thought in the same way about evolution as scientists do today. Our modern view of Darwin as a secular saint, strangely ahead of his time, is mistaken and revisionist. Early nineteenth-century biologists saw the development of an embryo as a mirror to its position in the animal kingdom, each stage in its development corresponding to some evolutionary stage in the wider world. But it was not always so.