UW and the Hubble

The captain of the space The captain of the space shuttle, Atlantis, which shuttle, Atlantis, which took off yesterday to fix took off yesterday to fix the Hubble is a UW the Hubble is a UW graduate in engineering.graduate in engineering.

The mission includes a The mission includes a new camera that UW new camera that UW faculty in aeronautics and faculty in aeronautics and astronautics helped astronautics helped develop.develop.

Hubble’s 19th anniversary

April 21 this yearApril 21 this yearReleased one of most Released one of most

interesting picturesinteresting picturesA peculiar set of galaxies A peculiar set of galaxies

called Arp 194: several called Arp 194: several galaxies and a cosmic galaxies and a cosmic fountain (of stars, gas, fountain (of stars, gas, and dust) that stretches and dust) that stretches over 100,000 light yearsover 100,000 light years

The blue: star forming The blue: star forming regionsregions

Scientific ExplanationEvolution and medicineEvolution and medicine HIV virus: RNA-based retrovirusHIV virus: RNA-based retrovirus Replicates at a fast rateReplicates at a fast rate Low copying fecundityLow copying fecundity So lots of mutationsSo lots of mutationsIf all of the various “cocktails” stop working for a If all of the various “cocktails” stop working for a

patient with HIV, frequently he or she and their patient with HIV, frequently he or she and their doctor will gamble:doctor will gamble:

Take the patient off all medications so that the “wild Take the patient off all medications so that the “wild type” re-emerges and blast it with meds that once type” re-emerges and blast it with meds that once worked.worked.

Scientific Explanation Why sex?Why sex?

It is expensive in lots of ways…It is expensive in lots of ways… But it allows for diversity of one’s offspring which But it allows for diversity of one’s offspring which

might protect them in terms of new challenges (new might protect them in terms of new challenges (new pathogens, other environmental changes, etc.)pathogens, other environmental changes, etc.)

The guppies in poolsThe guppies in pools The Red Queen hypothesis…The Red Queen hypothesis… Not an explanation of how sex initially evolved Not an explanation of how sex initially evolved

(still an ongoing research question)(still an ongoing research question) Natural selection can’t “look forward” (it’s blind and Natural selection can’t “look forward” (it’s blind and

dumb) dumb)

Scientific Explanation Sexual selection (Darwin)Sexual selection (Darwin)

Male/male competition for femalesMale/male competition for females Female choice of matesFemale choice of mates To take care of apparent counter-examples to natural To take care of apparent counter-examples to natural

selectionselection Parental Investment Theory (1960s)Parental Investment Theory (1960s)

Gametic dimorphism (sperm are small, numerous, and Gametic dimorphism (sperm are small, numerous, and “cheap”; eggs are large, relatively few, and “expensive”) “cheap”; eggs are large, relatively few, and “expensive”) as are other aspects of reproduction that often fall on as are other aspects of reproduction that often fall on females (egg sitting, gestation, lactation, caring for females (egg sitting, gestation, lactation, caring for young in general…)young in general…)

So parental investment differs by sex…So parental investment differs by sex…

Scientific Explanation Parental Investment Theory (1960s)Parental Investment Theory (1960s)

Gametic dimorphismGametic dimorphism This difference is supposed to explain the 2 This difference is supposed to explain the 2

processes that make up sexual selection.processes that make up sexual selection. Is also supposed to explain sex differences in Is also supposed to explain sex differences in

temperament, behavior, and mating strategiestemperament, behavior, and mating strategies ““It pays males to be promiscuous and it pays females It pays males to be promiscuous and it pays females

to be choosey”to be choosey” So it is also supposed to explain “The battle between So it is also supposed to explain “The battle between

the sexes”the sexes” And so-called double standards in numerous culturesAnd so-called double standards in numerous cultures

Scientific Explanation Parental Investment Theory (PIT, 1960s)Parental Investment Theory (PIT, 1960s) Challenges and current statusChallenges and current status From within evolutionary biology: From within evolutionary biology:

If sexual selection is a force at all, its role is very minor (Ernst If sexual selection is a force at all, its role is very minor (Ernst Mayr)Mayr)

Many cases previously explained using PIT or SS turn out to Many cases previously explained using PIT or SS turn out to be explicable using natural selectionbe explicable using natural selection

Sperm are not cheap to produce (Richard Dawkins)Sperm are not cheap to produce (Richard Dawkins) Gender stereotypes shape the theory and the observations Gender stereotypes shape the theory and the observations

made by those who assume itmade by those who assume it Females were supposed to be monogamous… but songbirds Females were supposed to be monogamous… but songbirds

in film…in film… Ordinary chimpanzees vs. BonobosOrdinary chimpanzees vs. Bonobos In fact, most species spend less time courting and mating In fact, most species spend less time courting and mating

than many other activitiesthan many other activities Evolutionary psychologists still maintain it.Evolutionary psychologists still maintain it.

van Fraassen’s account Explanation is not a formal relationship (defined in

terms of logic) between a law-like statement and some phenomenon

Many scientists and philosophers now see “understanding’ rather than explanation and prediction as the primary goal of science

Explanation in science is a pragmatic relationship – context and practice dependent:

“Why” questions are asked, and regarded as answered, within specific scientific contexts

To understand them (and what will count as an answer) requires knowledge of the scientific context within which they are asked.

van Fraassen’s account Reminders:

Answers to a question such as “why sex?” will greatly vary depending on context (religious vs. scientific, and within different scientific epochs)

So, too, the question “how did humans come into existence?”

And “how are humans like other animals and how (if at all) are they unique?”

And “why is nature uniform?”

van Fraassen’s account “The Evolutionary Arms Game”

Struggle for existence Why diversity, enabled by sex, matters in terms

of potential dangers and survival Evolution at work: Antibiotic resistant viruses (TB, HIV, …) Early exposure and immunity

Review

ReviewYou should know

What Hume’s “problem of induction” isWhat the remaining problem of induction is and how it applies to scienceWhat narrow inductivism isWhat Hempel’s new account of inductivism isWhat the distinction is between discovery and justification in the philosophy of science

ReviewYou should know

What the logic of confirmation isWhat Falsificationism isWhat the logic of falsification isChallenges to both Hempel’s logic of confirmation and Popper’s logic of falsificationWhat holism is and what Duhem’s argument for it isWhat the logic of “reductio ad absurdum” involvesAnd why Duhem says it cannot be properly used in science

ReviewYou should know

What “normal science” is according to Kuhn and how it is different from “pre-science” or “pre-normal science”The relationship between a paradigm and a normal science research programWhat Kuhn means by “puzzle solving” and how he uses it to describe the activities in normal scienceThe significant differences between The significant differences between Popper’s account of scientific practice and Popper’s account of scientific practice and Kuhn’sKuhn’s

ReviewYou should know

What an “ad hoc hypothesis” isWhat an auxiliary assumption isCases in which the latter were clearly at work in apparent “falsifications”Cases in which an added hypothesis (to take care of a problem) was confirmed (thus, not ad hoc)Difficulties in determining, except in hindsight, when a hypothesis is ad hoc

ReviewYou should know

What Hempel’s D-N model of explanation isWhat problems it facesWhat van Fraassen’s “pragmatic” account of explanation is and how it challenges Hempel’s modelHow questions like “Why Sex?” and those addressed in “The Evolutionary Arms Race” fit better with van Fraassen’s account