A biologist appropriately coined the word “estrus” by borrowing the Greek name for the stinging gadfly that harasses cattle. This large insect deposits its microscopic eggs under the beast’s tough hide. When the gadfly’s eggs mature into larvae, their squirming drives the host animal mad with itching. Sexual desire’s most apt metaphor is an itch that must be scratched. (The intense frictioning of human coitus is an exceedingly complicated form of scratching an itch.) The human female is the only mammalian species who we know for sure has lost estrus (or its equivalent). However, what she lost, he seems to have gained; a young male of the human species exhibits ample behavioral indicators signifying that he is in a state of full-blown “estrus” all the time.

– Leonard Shlain, Sex, Time, and Power: How Women’s Sexuality Shaped Human Evolution (2003)


The vast majority of creatures do not have an awareness of self, and therefore are incapable of deluding themselves. Those few that do possess self-awareness (e.g., apes, dolphins, elephants) do not possess sufficient mental acuity to engage in serious self-deception. Observers have documented numerous instances of chimpanzees employing sophisticated subterfuge in their social interactions, but they do not appear to turn this behaviour inward. Only humans, endowed with a hyperactive (and, in some cases, riotous) imagination, can fool themselves.

– Leonard Shlain, Sex, Time, and Power: How Women’s Sexuality Shaped Human Evolution (2003)

Every time I read another report in the newspapers of an African disaster—a famine in Ethiopia, a war in Namibia, ethnic conflict in Burundi—I wonder how much good it does to correct the theories with which these evils are bound up; the solution is food, or mediation, or some other more material, more practical step. And yet, the shape of modern Africa (the shape of our world) is in large part the product, often the unintended and unanticipated product, of theories; even the most vulgar of Marxists will have to admit that economic interests operate through ideologies. We cannot change the world simply by evidence and reasoning, but we surely cannot change it without them either.

– Kwame Anthony Appiah, In My Father’s House: Africa in the Philosophy of Culture (1992)