Sex, Time, and Power by Leonard Shlain (MD) is book that speculates on why Humans evolved their intelligence including speech. This book is only his speculation and nothing more. While some of the things he mentions are scientific theories that are generally accepted in the scientific community, others are merely his ideas. I found this a fascinating read that I enjoyed except for the last five chapters. This book is very general public friendly without totally simplifying the biological concepts that it is based on.
Leonard speculates that for any major evolution to occur a species had to have some selection pressure, meaning something has to be essentially going "wrong" with the organism to force it into major change (not exactly true—but will work for these purposes). So what was wrong with the precursor to Homo sapiens to cause the changes such as walking upright and our intelligence boost? Plus why is our reproduction timing system so different than all other mammal species? These are the questions that Leonard offers his explanations for in the course of the book.
The book is divided into five parts: Iron, Sex and Women; Iron, Sex and Men; Sex and Time; Death and Paternity; and Men and Woman.
In the first part, Leonard discusses the crisis that made us evolve. It seems due to the large size of our head at birth, there are many complications in birth--Humans have the hardest time giving birth (and before modern medicine more women died) than any other animal. That made us evolve. He says at some point some woman figured out sex equals birth may cause death. That gave women a choice, an important choice, to risk death to reproduce or not. This choice leads into why we have such a blood loss during menses--no other animal has such a blood loss as ours--which also leads into the second section.
If women are choosing to not have sex so end the species. So something needed to evolve to encourage women to have sex. Therefore, women are cursed with several things that cause blood loss, which equates into iron loss. Iron is necessary in red blood cells, which is necessary to equip our large brain with oxygen. We recycle iron in our bodies, but women loose iron like a sieve. We loose iron in menses, breast-feeding, and it is stolen from us by pregnancy, which causes a need to replace it. Iron is not easily nor in high quantities recovered from digesting plant material. The best way to replace iron is to eat red meat. So Leonard hypothesizes, that men became hunters in order to trade meat (iron) for sex. That way the species is furthered.
In his third section, Sex and Time, Leonard speculates that it was women who figured out the concept of time. This leads to better hunting strategies, and our ability to plan things for the future and our ability to remember past things. This observation comes from the cycling of women’s menses with moon cycles. Our ability to use time is a powerful tool for Humans. It’s also in this section that Leonard talks about courting and what had to change due to our evolution including the development of speech. This discussion leads into a discussion of the "level" of maleness and femaleness within each of us. He also discusses reasons why same sex relationships would have evolved genetically and been a benefit to the early hunting societies (which was one of the most interesting sections of the book).
In the forth section, Leonard discusses that us "discovering" time causes the realization that someday we will die (we are the only organism that seem to realize this). This bothers men more than women--which lead to men discovering paternity (sex with woman leads to child that looks like me). This alleviates some the stress of death since something of himself lives on in the child. This leads to the need to know if the child is really his, which leads to some of the repression of women activities that have sprung up in society. This suppression of women is discussed in the fifth section, and seems to be his real reason to write the book.
I thought this book was well written and thought out until the latter part of the book. He discusses Haeckel's theory of ontogeny recapitulates phylogeny (p270). This is a theory that an embryo goes through development phases that resemble past organisms it evolved from. He was comparing it to the maturation of human society? Haeckel's theory is generally thought to be bunk in evolutionary biology (Haeckel's drawing which is primary "evidence" were tampered with--he drew what he needed for the theory not what was actually seen). As an evolutionary biologist seeing Haeckel’s theory used once again bothered me. Plus in the latter half of the book starting ch. 20 of part 4 sounds more like a fiction novel reconstruction than a laid out scientific argument, but up until then the book is nicely written and argued.
He has done several good things in this book--I learned a few things (and I am a PhD student in evolutionary biology), but it is not written so that it would confuse or lose someone who has no training in biology. All the theories he discusses are simplified and explained without losing the essence of the theory. I would recommend it to all women (you will learn some things about yourself) and any man with an interest in the topic. This would be a great reading circle book--it would fuel some great discussions, and in the trade paperback copy, which I read, there is a reader's guide inside.
Recommended:
