Download Evidence can be “indirect” or “inferential”

Science news
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Lots of it is about “gene therapy”
Early (bad) problems:
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Recent successes
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Results not reproducible
And some deaths
“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”
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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.)?
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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?
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Study, again, of the history and some contemporary examples
of science
Kuhn on “normal science”
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What is his argument for the claim that normal science involves
lots of puzzle solving?
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What is his argument for the claim that normal science is more
fruitful and more scientific than prescience?
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His own experience as a scientist and his study of scientific practice
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
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Hempel: The DN model of scientific explanation
 Deductive
(in the case of deterministic laws)
 Nomological (theory involving laws)
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E (that to be explained):
 “Uh,
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oh. My radiator fluid froze last night.”
L (relevant law or laws):
 Relatively pure
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water freezes at 32° F
C (relevant initial conditions)
 The
temperature was 30 ° F for 8 hours last night
Scientific Explanation
Also works as a model of prediction…
 E (that predicted):
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 “Uh,
oh. My radiator fluid will freeze tonight unless I
add anti-freeze to it.”
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L (relevant law or laws):
 Relatively pure
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water freezes at 32° F
C (relevant initial conditions)
temperature is predicted to be 30 ° F for 8
hours tonight
 The
Scientific Explanation
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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 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:
1.
L1, L2 … Ln
2.
C1, C2 … Cn
--------------------E
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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
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
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Answers to a question such as “why sex?” will
greatly vary depending on context (religious vs.
scientific, and within different scientific epochs)
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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 account
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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 Explanation
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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)
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 Natural
dumb)
selection can’t “look forward” (it’s blind and
The Ghost Particle:
Searching for Neutrinos
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A particle with no charge and almost no mass
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Predicted by The Big Bang Theory
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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…”
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…
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The Ghost Particle:
Searching for Neutrinos
My friend, physicist Eric Thrane
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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
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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
Searching for Neutrinos:
Eric Thrane in Japan