UW and the Hubble

1. UW and the Hubble • The captain of the space shuttle, Atlantis, which took off yesterday to fix the Hubble is a UW graduate in engineering. • The mission includes a new camera that UW faculty in aeronautics and astronautics helped develop.

2. Hubble’s 19th anniversary April 21 this year Released one of most interesting pictures A peculiar set of galaxies called Arp 194: several galaxies and a cosmic fountain (of stars, gas, and dust) that stretches over 100,000 light years The blue: star forming regions

3. Scientific Explanation Evolution and medicine • HIV virus: RNA-based retrovirus • Replicates at a fast rate • Low copying fecundity • So lots of mutations If all of the various “cocktails” stop working for a patient with HIV, frequently he or she and their doctor will gamble: Take the patient off all medications so that the “wild type” re-emerges and blast it with meds that once worked.

5. Scientific Explanation • Why sex? • It is expensive in lots of ways… • But it allows for diversity of one’s offspring which might protect them in terms of new challenges (new pathogens, other environmental changes, etc.) • The guppies in pools • The Red Queen hypothesis… • Not an explanation of how sex initially evolved (still an ongoing research question) • Natural selection can’t “look forward” (it’s blind and dumb)

6. Scientific Explanation • Sexual selection (Darwin) • Male/male competition for females • Female choice of mates • To take care of apparent counter-examples to natural selection • Parental Investment Theory (1960s) • Gametic dimorphism (sperm are small, numerous, and “cheap”; eggs are large, relatively few, and “expensive”) as are other aspects of reproduction that often fall on females (egg sitting, gestation, lactation, caring for young in general…) • So parental investment differs by sex…

7. Scientific Explanation • Parental Investment Theory (1960s) • Gametic dimorphism • This difference is supposed to explain the 2 processes that make up sexual selection. • Is also supposed to explain sex differences in temperament, behavior, and mating strategies • “It pays males to be promiscuous and it pays females to be choosey” • So it is also supposed to explain “The battle between the sexes” • And so-called double standards in numerous cultures

8. Scientific Explanation • Parental Investment Theory (PIT, 1960s) • Challenges and current status • From within evolutionary biology: • If sexual selection is a force at all, its role is very minor (Ernst Mayr) • Many cases previously explained using PIT or SS turn out to be explicable using natural selection • Sperm are not cheap to produce (Richard Dawkins) • Gender stereotypes shape the theory and the observations made by those who assume it • Females were supposed to be monogamous… but songbirds in film… • Ordinary chimpanzees vs. Bonobos • In fact, most species spend less time courting and mating than many other activities • Evolutionary psychologists still maintain it.

9. 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.

10. 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?”

11. 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

12. Review

13. Review You should know What Hume’s “problem of induction” is What the remaining problem of induction is and how it applies to science What narrow inductivism is What Hempel’s new account of inductivism is What the distinction is between discovery and justification in the philosophy of science

14. Review You should know What the logic of confirmation is What Falsificationism is What the logic of falsification is Challenges to both Hempel’s logic of confirmation and Popper’s logic of falsification What holism is and what Duhem’s argument for it is What the logic of “reductio ad absurdum” involves And why Duhem says it cannot be properly used in science

15. Review You 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 program What Kuhn means by “puzzle solving” and how he uses it to describe the activities in normal science The significant differences between Popper’s account of scientific practice and Kuhn’s

16. Review You should know What an “ad hoc hypothesis” is What an auxiliary assumption is Cases 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

17. Review You should know What Hempel’s D-N model of explanation is What problems it faces What van Fraassen’s “pragmatic” account of explanation is and how it challenges Hempel’s model How questions like “Why Sex?” and those addressed in “The Evolutionary Arms Race” fit better with van Fraassen’s account