“Good” Science vs. “Bad” Science
Syllabus?
Website?
Slides from last class
Questions?
Assignment #1 posted
Pathological Science &
Pseudoscience
How not to …
and the baloney kit
Crop circles
•
Theory 1: UFOs
•
Theory 2: humans are responsible
Theory 2 consistent with Occam’s razor
Be skeptical!
The virtue of simplicity
•
Occam’s Razor (William of Occam 1284-1347): “...
entities must not be multiplied beyond what is
necessary”  law of parsimony or Occam’s razor
•
Isaac Newton (1642-1726): “We are to admit no more
causes of natural things than such as are both true and
sufficient to explain their appearances. To this purpose
the philosophers say that Nature does nothing in vain,
and more is in vain when less will serve; for Nature is
pleased with simplicity, and affects not the pomp of
superfluous causes.”
Sagan article
•
Read article by the late Carl Sagan 1934-1996
•
Comments?
•
Questions?
Airplane crash dreams
analysis of rare events
•
Say there are 150,000,000 adults in US
•
Say 1 in 3 have such a dream once in their lifetime 
50,000,000 dreams
•
Adult life span = 30 yrs x 365 days/yr = 10,000 days 
5,000 dreams/day
•
Say 10% are vivid, lurid, even accurate
•
 500 new psychics every time there is a crash!
People cheat
Shooting of President Reagan on 3/30/1981 was “predicted”
Scientists are also people so some of them also cheat
•
Lucent scientist fabricated data
Scientific Misconduct: Hendrik Schön
• 1998-2002: at Bell Labs, Schön authors or co-authors over 100
papers. Some of these papers claimed significant advances in a
variety of fields: organic semiconductors, organic superconductors,
inorganic superconductors, and fullerenes.
• Late 2001: researchers find obvious discrepancies in data.
• May 2002: Bell Labs convenes an inquiry committee, chaired by
Malcolm R. Beasley (Stanford).
• September 24, 2002:, the committee of inquiry concludes that
Schön had committed scientific misconduct by manipulating and
misrepresenting data, substituting mathematical functions for data,
and creating false data. Schön was immediately fired.
• Clean-up of the mess in the literature is continuing.
Bad Science
Pathological Science: Irving Langmuir
Chemistry Nobel Laureate
“These are cases where there is no dishonesty involved but where
people are tricked into false results by a lack of understanding
about what human beings can do to themselves in the way of
being led astray by subjective effects, wishful thinking or
threshold interactions. These are examples of pathological
science. These are things that attracted a great deal of attention.
Usually hundreds of papers have been published on them.
Sometimes they have lasted for 15 or 20 years and then gradually
have died away”.
Characteristics
of Pathological Science (Langmuir)
•
The maximum effect that is observed is produced by a causative agent of
barely detectable intensity, and the magnitude of the effect is substantially
independent of the intensity of the cause
•
The effect is of a magnitude that remains close to the limit of detectability
or, many measurements are necessary because of very low statistical
significance of the results
•
There are claims of great accuracy
•
Fantastic theories contrary to experience are suggested
•
Criticisms are met by ad hoc excuses thought up on the spur of the
moment
•
The ratio of supporters to critics rises up to somewhere near 50% and
then falls gradually to oblivion
Examples of Bad Science
•
N rays Blondlot
•
Quake predictions Browning
•
Cold fusion Pons & Fleischman
N Rays & Blondlot
Time of X-rays (1903)
•
Hot wire in iron tube with aluminum window
•
Rays come out through aluminum window (not iron)
•
Rays fall on object and are barely visible  sit in the dark for a long time
•
“Helped seeing in the dark”
•
Rays could be stored in bricks; if you kept the brick close to your head, the rays
would help you see better
•
Prism would split N rays and he could measure refractive indices to very high
accuracy
Enter Wood: observed him and saw that results were inconsistent with ordinary
optical phenomena: “They don’t follow the ordinary laws of physics …” Wood asked
him to repeat the experiment but put the prism in his pocket! Results came out as
before!
•
Then Wood published and the whole story collapsed
Iben Browning & the New Madrid Fault
•
New Madrid Fault: 4 earthquakes in 1811
and 1812, estimated at 7 to 7.9 on the
Richter scale.
•
December 1989: Iben Browning
predicts a 50% chance of a major
earthquake around Dec. 3rd, 1990.
Original theory based on tidal forces;
specific prediction on unknown
methodology. Browning had no
credentials in seismology...
Cold Fusion
• 1989 Press conference by Pons & Fleischmann : fusion under normal lab
conditions
• Implications potentially huge (this course would be very different if
claim correct)
• No paper published (retracted) no reproducible results (in the end)
• Briefly pitted chemists against physicists
• Lawyers involved
• Some people still working on this (but no federal funding)
The paranormal, ESP etc.
•
Claims that humans can exert or experience forces
with varying degrees of conscious control that are
not part of the known forces of nature
•
Known forces depend on distance, psi phenomena
apparently indifferent to it
•
Parapsychological Lab at Duke 1927 (Rhine)
Cards you guess at before being turned over (telepathy)
Looking for extrasensory perception
Or read the mind of the person turning the cards
Rhine got significant “results” by eliminating the numbers from
people who didn’t “like” him
Carl Sagan’s baloney kit tools for skeptical thinking
•
Whenever possible there must be independent confirmation of the “facts”
•
Encourage substantive debate on the evidence by knowledgeable proponents of all
points of view
•
Arguments from authority carry little weight (there are no authorities in science at
most experts)
•
Try different explanations
•
Don’t get attached to one hypothesis because it’s yours
•
Quantify
•
In a chain of arguments every link including the premise must work
•
Occam’s razor: choose the simplest explanation that explains the data
•
Ask if the hypothesis can be falsified. If not, it’s not worth much
•
Rely on carefully designed and controlled experiments
Pseudoscience
A pseudoscience is a set of ideas based on theories put
forth as scientific when they are not scientific
Examples: •
Based on authoritative texts: Creationists make
observations only to confirm infallible dogmas, not to
discover the truth about the natural world  static and no
new scientific discoveries or improved understanding of
the natural world
•
Some pseudoscientific theories explain what non-believers
cannot even observe
•
Some can't be tested because they are consistent with every
imaginable state of affairs in the empirical world
Books / articles
Carl Sagan
•
“The demon-haunted world - science as a candle in the dark”
Robert Park
•
“Voodoo Science: the road from foolishness to fraud”
Michael Friedlander
•
“At the fringes of science”
Irving Langmuir
•
“Pathological Science”
•
Physics Today October 1989 p.36
Do a little science …
• How do we know what we know?
– About the world?
– About the universe?
• Why is the Earth round?
– Earth’s shadow on the moon is …
– North Star
– Ships & the horizon
Measure the size of the Earth
• Suggestions for doing this 235 BCE?
• Consider
Earth is round
Find angle α
Measure AB
A
α
B
Because:
α
AB
=
360 circumference
Still measuring …
How to find α?
Use the sun: assume light rays are straight & parallel
 shadows
Note the equal angles
Distance AB can be measured
any time
but should be large (why?)
Measurement of shadows gives angles;
but should be done at the same time!
Eratosthenes was smart:
There are special times and places during the year
when/where we know what the shadow will be:
Tropic of Cancer, June 22 : sun directly overhead at noon  no shadow
Don’t have to go there to measure; can stay at home!
Eratosthenes (276-195 BCE), head of the library in Alexandria
figured out how to do it :
Alexandria is due north of Syene (Aswan) which is on the TofC
Measure on June 22 in Alexandria!
Result: shadow 1/8 of pillar
shadow
α