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Lecture 4 (re-ordered)

Lecture 4 (re-ordered)

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Lecture 4 (re-ordered)

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  1. Lecture 4 (re-ordered) • Film continued • Discussion • (Yet) more leftovers • A.J. Ayer on “verifiability” • Discussion

  2. Part I The Elegant Universe continued

  3. The Elegant Universe • Note the title! The universe is “elegant”! • String Theory: everything there is is made of tiny vibrating strings of energy… (not some one or more particles!) • Goals: a grand theory of everything! • Unifying physics • Resolving the contradictions between the 2 pillars of contemporary physics: • Quantum theory • Relativity

  4. The Elegant Universe • Relationships to course issues • More positing of unobservable objects (strings, 6 or 7 more dimensions, parallel universes, multiple “Big Bangs”, etc.) • Quest for simplicity/unity; One and the Many; Reality vs. Appearances • The Demarcation Problem: • Is String Theory testable? • If not, is it science?

  5. The Elegant Universe • Issues that once faced (or continue to face) String Theory • Testable? (If not, is it scientific?) • Anomalies: • Contradictions of 1 and/or 2 sorts: • Empiricalinconsistency (the apparently retrograde motion of Mars for the Aristotelian theory of the (then known) universe) • Mathematical and/or logical inconsistency (internal to a theory and allowing any and all consequences to follow “validly”)

  6. Part II Discussion

  7. The Elegant Universe • What do particle physicists (such as Democritus and Lederman) and String Theorists have in common in terms of assumptions? • Metaphysical/ontological? • Methodological? • Epistemological? • Technological? • Aesthetic? • Is there some (general) argument Lederman and Greene both offer to justify their theories and reasoning?

  8. Part III (Yet) more leftovers

  9. Leftovers • For a great episode on the discovery of and years of work to put Ardi together: www.pbs.org/newshour/videos • For a great read every Tuesday: www.nytimes.com: “Science Times” • How did Lucy get her name? • Ardi on the Discovery channel

  10. Leftovers • The evidence for subatomic particles – and for evolutionary processes and events – is indirect • We draw inferences from what we can observe to what we cannot • In evolutionary theorizing (as well as other historical sciences such as geology, cosmology, paleontology, and archaeology), scientists often reason along the lines of “reverse engineering”: • Start with some trait and attempt to explain it by reference to variations in an ancestral population and selection pressures. • This assumes that traits that proliferate are the product of R&D/evolutionary forces

  11. The Panda’s Thumb O: the panda’s “thumb” (TPT) and what it actually is (an enlarged wrist bone) H1: TPT came about through natural selection: the (blind) tinkering with available parts that gave those ancestors with it an advantage and, thus, the trait spread. H2: TPT was designed by perfect engineer. Gould: P(O/H1) >> P(O/H2) An example of inference to the best explanation

  12. Paley’s reasoning updated… • Not random? • After all, mutations are often random… and they underlie phenotypic/morphological/behavioral change… • True, but NS is not itself a random process. • Consider it to be an algorithm… • Like long division? • No. • More like an elimination tournament in tennis.

  13. The algorithm of natural selection

  14. The algorithm of natural selection • Waves of competition among con-specifics who vary • Selection pressures such that some variation or variations provide an advantage (however small) Results: • Winners (survive and reproduce better) and losers • Winners tend to pass on the relevant traits to their offspring

  15. Darwin’s orchids • Non-sexual reproduction is cheaper, but sexual reproduction insures that an organism’s progeny are varied (and thus will have a better chance of survival if conditions change). • From the same relatively primitive petal of its ancestor, varieties of orchids have different “contraptions” for insuring cross-pollination

  16. QWERTY PHENOMENA Like the arrangements of the keys on a keyboard, QWERTY phenomena are phenomena that show signs of history: a history of R&D (research and development) using what’s available, and limited or directed by contingencies and constraints… Francis Crick called them “frozen accidents” QWERTY phenomena abound in the organic world.

  17. QWERTY PHENOMENA In our case: Wisdom teeth, the blank spot in the center of each of our eyes, the possibility of retinal detachment, our “tail bone”, our back problems, (perhaps) our appendix, relatively short gestational period, male nipples…. Other cases: blind fish in dark caves, with eyes that don’t function, but whose ancestors had functioning eyes blind fish in dark caves, without eyes, whose ancestors did have eyes “toothless” species of whales in which embryos have teeth and lose them during natal development

  18. Part IV Verifiability as the criterion that distinguishes science from “pseudo” science

  19. What distinguishes science from pseudo-science? • Logical Positivism: • Science should and must be a positive force for human wellbeing • Logical Empiricism (same movement): • Working to identify the role of logic and that of experience in the workings of genuine science. • Both emphases underlie the work to identify the criterion (or criteria) that demarcate science (i.e., distinguish it from) “pseudo-science” and “non-science”.

  20. What distinguishes science from pseudo-science? • Logical Positivism/ Logical Empiricism • What motivated (and still does…) the question? • Then: • The rise of Nazism and fascism • Science as an antidote to ideologies • Nazism claims “scientific status” for its claims • The “semi-eclipse” of Newtonian mechanics by Relativity

  21. What distinguishes science from pseudo-science? • A.J. Ayer • A Logical Positivist • His target as “pseudo-science” (“nonsense” or without meaning): statements that cannot be verified by experience. • His criterion for literal/factual significance: verifiability • A sentence is verifiable if and only if there are observations that could verify it (demonstrate it is true). • Verifiability comes to be accepted as that which marks genuinely scientific claims, hypotheses, theories

  22. What distinguishes science from pseudo-science? • If there are no such observations, it is not literally or factually significant … but “nonsense” • Compare: • “The Absolute … does not enter into change.” • “There are mountains on the far side of the moon.” • “The universe began with The Big Bang.”

  23. Part V Discussion

  24. Discussion of Ayer • Does “the demarcation problem” matter today? • How does Ayer’s criterion of verifiability help, if it does, in today’s context? • How does it not? And, if not, why not?