"The pattern of sex differences found in our species mirrors that found in most mammals and in many other animals. As such, considerations of parsimony suggest that the best explanation for the human differences will invoke evolutionary forces common to many species, rather than social forces unique to our own. When we find the standard pattern of differences in other, less culture-bound creatures, we inevitably explain this in evolutionary terms. It seems highly dubious, when we find exactly the same pattern in human beings, to say that, in the case of this one primate species, we must explain it in terms of an entirely different set of causes — learning or cumulative culture — which coincidentally replicates the pattern found throughout the rest of the animal kingdom. Anyone who wishes to adopt this position has a formidable task in front of them. They must explain why, in the hominin lineage uniquely, the standard evolved psychological differences suddenly became maladaptive, and thus why natural selection “wiped the slate clean” of any biological contribution to these differences. They must explain why natural selection eliminated the psychological differences but left the correlated physical differences intact. And they must explain why natural selection would eliminate the psychological differences and leave it all to learning, when learning simply replicated the same sex differences anyway. How could natural selection favor extreme flexibility with respect to sex differences if that flexibility was never exercised and was therefore invisible to selection?"

“From a comparative perspective, we are a relatively monomorphic mammal, with relatively monomorphic minds.”

“The idea that women are the choosier sex is one of the best-known claims associated with EP . Ironically, another of the best-known claims associated with EP is an exception to this rule: On average, men are choosier than women when it comes to the physical attractiveness of a prospective mate. Even if we put this counterexample aside, though, the statement “females are choosier than males,” although true of many species, does not apply easily to our own. It is true that men may sometimes be more willing than women to lower their standards for a casual sexual partner. However, when it comes to the most important mating decisions of a man’s life — who he will marry, who he will have children with — the difference in choosiness is much smaller and maybe nonexistent. This fact of human life is even implicit in everyday folk psychology; the stereotype is that men will “sleep with anything that moves,” not that they will marry or have children with anything that moves. In long-term, committed relationships, men are about as choosy as women.”

“Changes in the inhabitants of the earth do not reflect a constant process of improvement in the design of organisms, any more than changes in fashion over the years reflect a constant process of improvement in the quality of clothing.”

“One could even argue that our creative endeavours and achievements and small acts of kindness are all the more impressive against the backdrop of a purposeless universe.”

“We like to think that reason is the supreme adaptation; that rational animals deserve preferential treatment; and that nonhumans, because they don’t have reason, have no intrinsic moral value. However, after Darwin, this is no different and no more convincing than, say, an elephant thinking that trunks are the supreme adaptation; that animals with trunks deserve preferential treatment; and that non-elephants, because they don’t have trunks, have no intrinsic moral value.”

“Of course, nothing can be said to argue that people are morally obliged to accept this ethic, for to do so would be inconsistent with the ideas that inspired it in the first place. It is an ethic that will be adopted – if at all – by those who find a certain stark beauty in kindness without reward, joy without purpose, and progress without lasting achievement.”