Reading Assignment: Why We Get Sick: The New Science of Darwinian Medicine, pp. ix-12.
 

Preface, pp. ix-xi.

Who are the two authors?

Randolph Nesse a physician in the Dept. of Psychiatry at the U. of Michigan medical school; George Williams, a marine ecologist and leading evolutionary theorist.
 

Why was Randolph Nesse frustrated in psychiatry?

No theoretical foundation; fascinated by advances in animal behavior studies from evolutionary ideas.
 

What significance did Nesse see in George Williams's 1957 evolutionary explanation of aging?

If there was an evolutionary explanation of aging, why not also of anxiety disorders or schizophrenia or other psychological conditions or diseases.
 

What significance did Williams see in Paul Ewald s evolutionary treatment of infectious disease?

Ewald's 1980 article suggested to Williams that the scope of evolutionary ideas in medicine went well beyond infectious disease.
 

How is the present book related to Nesse & Williams s joint 1991 article "The Dawn of Darwinian Medicine"?

It is an expansion and development of it.
 

Do Nesse & Williams think that Darwinian Medicine is a miscellany of unrelated ideas or a

coherent new field?

They think it's a whole new field of medicine.
 

Does Darwinian Medicine promote health?

Ultimately, yes.
 

Are their examples meant to be medical advice or authoritative analyses?

They say no, only illustrations of the fecundity of evolutionary ideas, but I sometimes doubt their sincerity. Also, they have to be careful about giving medical advice.
 

Do Nesse & Williams reject conventional Western medicine? How are Darwinian and Western medicine related?

Absolutely not. They are complementary perspectives, one dealing with proximate causes (Western medicine), the other with ultimate causes (Darwinian medicine).
 

Chapter 1: The Mystery of Disease, pp. 3-12.

What is the baffling paradox with which the chapter opens?

"Why, in a body of such exquisite design, are there a thousand flaws and frailties that make us vulnerable to disease?"
 

What diseases do we know a lot about why particular people get them, but fail altogether to understand why they occur at all? Give some examples.

High-fat diet causes heart disease; solar exposure causes skin cancer. Why, then, do we crave fat and sunshine? Why can't our bodies repair clogged arteries and sun-damaged skin? Why does sunburn hurt? Why does anything hurt? Why are we still prone to streptococcal infection?
 

Formulate what Nesse & Williams call "(t)he great mystery of medicine". What bearing does it have on the theistic Argument from Design?

"The presence, in a machine of exquisite design, of what seem to be flaws, frailties, and makeshift mechanisms [Rube Goldberg devices] that give rise to most disease." Theists concentrate on the exquisite design, not on the shocking imperfections. [Recall the Italian nobleman who, having had the Ptolemaic theory explained to him, remarked that, if he had been present at the creation, he could have given the Creator some helpful advice.]
 

Can an evolutionary approach help solve this mystery? Piecemeal or wholesale?

Yes, it reshapes the mystery into a series of answerable questions. Both piecemeal and wholesale, as we will soon see.
 

Doesn't natural selection tend to produce organisms well adapted to their environments? Isn't it at least prima facie paradoxical, therefore, that natural selection hasn't eliminated the genes that make

us susceptible to these diseases, especially when the diseases are very old?

People overlook the fact that the result of natural selection is usually a cost-benefit compromise.
 

How well designed are our bones? Kidneys? Heart valves? Brains & nervous system? Hormonal system? Sensorimotor system? How well designed is the crossover of the trachea and the esophagus? Our optical lenses? Our arteries? Our immune system? The course of pregnancy? The aging process? Our food cravings? Male & female sexuality? Our anxiety mechanism?
 

Two Kinds of Causes (pp 6-7):

How do evolutionary causes differ from proximate causes? How are they related?

"Proximate explanations address how the body works and why some people get a disease and others don't. Evolutionary explanations show why humans, in general, are susceptible to some diseases and not to others. We want to know why some parts of the human body are so prone to failure, why we get some diseases and not others." The two are complementary.
 

What do proximate explanations do? Evolutionary explanations? What kinds of questions does each type of explanation try to answer.

"A proximate explanation describes a trait---its anatomy, physiology, and biochemistry, as well as its development from the genetic instructions provided by a bit of DNA in the fertilized egg to the adult individual. An evolutionary explanation is about why the DNA specifies the trait in the first place and why we have DNA that encode for one kind of structure and not some other." Evolutionary biology tries to explain what things are for, and how they got there.
 

Illustrate the difference between proximate and evolutionary explanations by sketching their respective accounts of the external ear and of taste buds. With which kind of explanation does Western medicine largely concern itself?

A proximate account of the external ear would describe and explain how it focuses sound; its tissue composition, its system of arteries, veins, and nerves; and its development from embryonic to adult form. An evolutionary account would explain what advantage ears confer, what disadvantage earless creatures labor under, and what ancestral structures were slowly shaped by natural selection to give the ear its present form. Similarly, for taste buds. Western medicine is obviously concerned with proximate explanations.
 

Is physiology concerned with function and purpose? Biochemistry? Are these disciplines

part of Darwinian medicine?

In a sense, yes, at least they ask what things are for, although not how they got there.
 

Is Darwinian medicine mostly speculative?

Though its hypotheses are often speculative, they are not mere speculation.
 

How does Margie Profet explain morning sickness? Is this a Darwinian account?

She suggests that the nausea, vomiting, and food aversions of early pregnancy (so-called morning sickness) evolved to protect the developing fetus from toxins. This analysis leads to the prediction that these symptoms should begin when fetal-tissue differentiation begins, and diminish when the fetus becomes less vulnerable to these toxins. Substantial evidence supports these predictions. This is a Darwinian account [as far as it goes; it doesn't explain how we got there], but it's not without its detractors.
 

Can evolutionary explanations make predictions about proximate mechanisms? Illustrate your

answer by invoking the low iron levels found in patients with infections? Is this a case where

Darwinian medicine makes a therapeutic recommendation?

The hypothesis that the body sequesters iron as a means of combatting infection (bacteria need iron to flourish) leads to the prediction that giving a patient iron may aggravate an existing infection, which is the case. Their disavowals aside, this seems like a therapeutic recommendation.
 

The Causes of Disease (pp. 8-11):

Nesse & Williams propose the below-enumerated six categories of evolutionary explanation as their formal framework for Darwinian medicine. Do they really constitute a formal framework for Darwinian medicine?

Hardly. They're more a miscellany of key items, than a formal framework for anything.
 

1. Defenses: Distinguish defects from defenses. Illustrate the distinction by invoking the signs of pneumonia. Is eliminating a defect usually a good idea? Ditto for defenses?

A defense is a happenstance with no particular utility. E.g., in pneumonia, the skin of a fair-skinned person becomes bluish (a defect) because hemoglobin becomes darker when it lacks oxygen; coughing is a defense, a complex mechanism designed to expel foreign matter from the respiratory tract.
 

2. Infection: In what sense are bacteria and viruses sophisticated opponents? To what arms race are Nesse & Williams alluding?

They evolve ways to overcome our evolved defenses, for which we then evolve new defenses, etc.
 

3. Novel Environments: For what kind of environment(s) was our bodies shaped by natural selection? What bearing does environmental mismatch have on disease and epidemics?

For hunter-gatherer groups on the plains of Africa. Organisms well adapted to such a life may be ill adapted to different environments.
 

4. Genes: Why are some genes perpetuated despite the fact that they cause disease? In your response, bring in genes with harmless quirks versus those with positive benefits. Are defective genes that result from mutation a serious health problem? What are outlaw genes? Do they pose a serious health problem?

They have benefits that outweigh their costs (e.g., the sickle cell gene prevents malaria), or their "quirks" were harmless in the environment in which they evolved, e.g., the genes that predispose to heart disease. Defective genes with no compensating benefits are eliminated or minimized by natural selection, and so are not a common cause of disease. Outlaw genes facilitate their own transmission at the expense of the carrier. They are not a common cause of disease because selection among individuals is a potent evolutionary force.
 

5. Design Compromises: Are design flaws always mistakes or sometimes compromises? If the latter, do they have benefits, even if hidden? Give examples.

Many, maybe most, are compromises, not mistakes. Walking upright disposes us to back problems.
 

6. Evolutionary Legacies: Is evolution incremental or saltational? How does history

constrain or encumber designers, natural selection included?

Incremental. At any time, natural selection has to work with what's then available. It can't go back to square one. That's one reason why we get such Rube Goldberg devices.
 

What We Are Not Saying (pp. 11-12):

Explain the connection between Darwinian medicine, eugenics, and Social Darwinism. How Darwinian is/was Social Darwinism? Does Darwinian medicine hold that disease, or at least some diseases, is good? What are the moral implications of Darwinian evolution?

No connection! Social Darwinism was Darwinian in name only. Nesse & Williams will "never argue that any disease is good, even though we will offer many examples in which pathology is associated with some unappreciated benefit." Darwinism is amoral.