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Science news Lots of it is about “gene therapy” Early (bad) problems: Results not reproducible And some deaths Recent successes “Curing” blindness of some kinds and to a degree “Arresting” a fatal syndrome Is there new life (one year more of funding) for the Tevatron?

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science news
Science news
  • Lots of it is about “gene therapy”
  • Early (bad) problems:
    • Results not reproducible
    • And some deaths
  • Recent successes
    • “Curing” blindness of some kinds and to a degree
    • “Arresting” a fatal syndrome
  • Is there new life (one year more of funding) for the Tevatron?
  • LHC is up and running (Nov. 7)!
kuhn on normal science
Kuhn on “normal science”
  • You were asked to look for Kuhn’s arguments for the claims outlined in the 2nd part of last lecture
  • What is his argument for the claim that science follows the kind of trajectory he outlines (e.g., prescience to normal science to crisis to revolution to new normal science tradition, etc.)?
    • This is the pattern one sees in the history of science.
  • What is his argument for the claim that, in normal science, the paradigm that underwrites all research is never questioned for a long period of time, despite anomalies?
    • Study, again, of the history and some contemporary examples of science
kuhn on normal science3
Kuhn on “normal science”
  • What is his argument for the claim that normal science involves lots of puzzle solving?
    • His own experience as a scientist and his study of scientific practice
  • What is his argument for the claim that normal science is more fruitful and more scientific than prescience?
    • That because there isn’t debate over fundamentals, detailed research can precede.
  • What is his account of a paradigm?
    • Consider the Leyden jar – a device
    • Consider the heliocentric model… natural selection… hypotheses…
    • All “thin” but otherwise somewhat different
scientific explanation
Scientific Explanation
  • Hempel: The DN model of scientific explanation
    • Deductive (in the case of deterministic laws)
    • Nomological (theory involving laws)
  • E (that to be explained):
    • “Uh, oh. My radiator fluid froze last night.”
  • L (relevant law or laws):
    • Relatively pure water freezes at 32° F
  • C (relevant initial conditions)
    • The temperature was 30 ° F for 8 hours last night
scientific explanation5
Scientific Explanation
  • Also works as a model of prediction…
  • E (that predicted):
    • “Uh, oh. My radiator fluid will freeze tonight unless I add anti-freeze to it.”
  • L (relevant law or laws):
    • Relatively pure water freezes at 32° F
  • C (relevant initial conditions)
    • The temperature is predicted to be 30 ° F for 8 hours tonight
scientific explanation6
Scientific Explanation
  • Hempel: Explanation is a formal (logical) relationship between kinds of statements – some reporting what is observed, others theoretical (carrying forward the empiricist tradition)
  • Some sciences (e.g., fields in biology) don’t include deterministic laws, but only statistical generalizations
  • Here the reasoning is inductive and the conclusions (explanations and predictions) only probable
scientific explanation7
Scientific Explanation
  • Hempel: Explanation is a formal relationship
  • It involves (typical of empiricists in the mid to late-ish 1990s) empirical data/observations/facts and logical reasoning (in the case of deterministic laws, the reasoning is deductively valid).
  • The model:
  • L1, L2 … Ln
  • C1, C2 … Cn

---------------------

E

scientific explanation8
Scientific Explanation

Evolution and medicine: How does HIV replicate in a way that challenges all anti-viral?

  • 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.

scientific explanation9
Scientific Explanation

Evolution and medicine: How does HIV replicate in a way that challenges all anti-viral drugs?

What is being assumed?

Natural selection

High mutation rate

How to counter the mutations (let the wild type become normal)

van fraassen s account
van Fraassen’s account
  • Answers to a question such as “why sex?” will greatly vary depending on context (religious vs. scientific, and within different scientific epochs)
    • Plato, Aristotle, and Aquinas: why are there females at all? Why didn’t (obviously superior to females) males just “clone” or reproduce among themselves?
    • In other cultures, sex is regarded as natural and divinely blessed
    • In some contemporary settings, sex may be necessary and need to be regulated, but it is far less “spiritual” than celibacy…
van fraassen s account11
van Fraassen’s account
  • Explanation is not a formal relationship (defined in terms of logical relationships between a law-like statement and a statement about 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.
scientific explanation13
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 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)
the ghost particle searching for neutrinos
The Ghost Particle:Searching for Neutrinos
  • A particle with no charge and almost no mass
    • Actually there are kinds of them; and if they have no mass that raises a problem… so what’s generally said is “experimental results are consistent with zero mass…”
  • Predicted by The Big Bang Theory
    • The neutrinos left over from the creation of the universe are the most abundant particles in the universe
  • First proposed to explain anomalies that challenged the conservation of energy and momentum
  • Every second, trillions of them pass through our bodies without us feeling a thing…
  • So the existence of the particles was predicted by accepted paradigms, even though they are kind of “spooky” and we are unable to directly “experience” them, and it took YEARS before anyone thought they were actually detecting them
  • A puzzle of normal science…
the ghost particle searching for neutrinos15
The Ghost Particle:Searching for Neutrinos
  • My friend, physicist Eric Thrane
    • Completed his PhD in physics at UW 2 years ago
    • Is a post doc at University of Minnesota
    • Got Jack and me an insider’s tour of Fermilab and the Tevatron when he was an intern in physics during summers he attended Northwest
    • We used to babysit him (GROAN)!
  • Here he is in the world’s best neutrino detector
    • Called the Super-Kamiokande Neutrino Detector
    • Inside Mount Ikenoyama in Japan
    • An active zinc mine contains 50,000 tons of water that is remarkably pure… thus allowing neutrino detections using 11,000 hand blown photomultiplier tubes