Nature isn’t just a bloodbath; it’s also a vast, unending orgy. - Steve Stewart-Williams

For much of the 20th century, the blank slate view was the dominant view in the social sciences. With the popularization of sociobiology in the 1970s, however, evolutionary approaches to human behavior became the locus of an academic culture war between biologically minded thinkers and advocates of the traditional social science model.

Human beings are, by nature, the kind of animal that falls in love. The cross-cultural record also suggests that humans are also the kind of animal that commonly provides biparental care for its young. In 95% to 97% of mammalian species, only the females care for the young. We would no more expect males in these species to invest in their offspring than we would expect them to get pregnant or lactate. Humans are not like that.

If we decide – and this is our decision; it’s not imposed on us from above – if we decide that reducing the amount of suffering in the world is a good ethical principle to live by, then it becomes entirely unjustified and arbitrary to extend this principle to human beings but not also to extend it to other animals capable of suffering. Why should the suffering of nonhumans be less important than that of humans? Surely a universe with less suffering is better than one with more, regardless of whether the locus of suffering is a human being or not, a rational being or not, a member of the moral community or not. Suffering is suffering, and these other variables are morally irrelevant.