An evolutionary approach is useful because it contributes to the explanation of the origin and development of the human being and society without prior ‘intelligent design’, and also clarifies the potential for their development, as well as its limitations. This applies to all areas of investigation in this book: knowledge, language, agency of the human being and morals/ethics.

As widely known, the logic of evolution is that of the threesome of variety generation, selection and transmission. In biology, variety generation takes the form of mutation of genes and conditions for their expression, and in sexual reproduction the cross-over of chromosomes. Lamarck held that characteristics acquired during life can be transmitted in reproduction. That idea was dropped because it is not clear how such experience could be incorporated in genes. However, it was later seen that genes often do not directly entail characteristics themselves, but a potential to produce them, in ‘gene expression’, as a function of the environment, in which experience does play a direct role. The colour of eyes is an exception, as determined more directly by genes.

That matters especially because in contrast with most animals, humans are born long before maturity, with further development in the environment in which they are born and brought up. That came about when the precursor of the human being started to stand and walk upright, which narrowed the pelvis as exit for the baby, while the human being also increased the size of its brain and with that the size of its skull, further blocking the baby's exit, necessitating early birth. The early birth makes for vulnerability and, as a result, the need for baby care. The growth of the brain, in turn, enabled the wider use of now freed hands, for tool use, and larger mental capacity for social interaction that was needed, among other things, for division of labour in child care, which in turn favoured a larger brain. That early birth makes for malleability, and social cooperation, which increases the potential for survival.