The Scientific Method
2/18/1996
…lots and lots and lots of math.
Goal
• What is the scientific method?
• What does the scientific method assume?
• Does the scientific method work?
• What is not a scientific argument.
• Does astrology follow the scientific method?
The Scientific Method
1. Observe an event.
2. Develop a model (or hypothesis) which makes a
prediction.
model
3. Test the prediction.
4. Observe the result.
5. Revise the hypothesis.
6. Repeat as needed. test
7. A successful hypothesis becomes a Scientific
Theory.
Medical Science
Scientific Method High Cholesterol
Observation Patient has high cholesterol
Hypothesis Certain chemicals may dissolve
(prediction) cholesterol deposits.
Test Give 100 patients these
chemicals, give 100 patients
placebo.
Observe result Same number lower their
cholesterol as placebo patients.
Revise Try different combo of chemicals.
hypothesis?
New test? Re-run medical test. Observe
results.
Everyday Science
Scientific Method Car Repair
Observation Engine won’t turn over.
Hypothesis (prediction) Predict battery is dead.
Test Replace battery.
Observe result Engine now turns over.
Revise hypothesis? Not needed.
New test? Not needed.
Scientific Theory Cars won’t work without a
fully charged battery.
Everyday Science
Scientific Method Making Spaghetti Sauce
Observation Spaghetti sauce should be red.
Hypothesis Try a tomato sauce.
(prediction)
Test Heat pot of tomato sauce.
Observe result Taste the sauce - bland.
Revise hypothesis? Use tomato sauce and garlic!
New test? Add garlic, taste - not so bland.
Scientific Theory The Final Recipe.
Food Science
• Throwing something together Hypothesis
• Your grandmother’s time-tested recipe
Scientific Theory.
Repeatability
• A successful theory is repeatable.
– By you.
– By anyone.
• Examples:
– Cold Fusion (1989)
– Ecstasy (Science, 2003)
Requirements
• Objective reality
– We all see the same world.
• Constant Laws of Nature
– What happens here, happens there.
– What happened yesterday will happen tomorrow.
• The Cosmos is knowable.
Does it work?
• Scientific Method is a tool.
• Does this tool work?
– Life expectancy
– Mortality rates
• Are there better tools?
Theories
• So: a theory is a highly successful
hypothesis.
• All hypotheses make predictions.
• All theories make predictions.
• All theories can be tested.
• Result: Any scientific theory is subject to
change as our ability to make tests, or make
observations of a test’s results, improves with
time.
Non-scientific Theories
• Make no predictions
• Un-testable
• Can’t be falsified
Non-scientific Theories
• Car won’t work? Aliens drained the battery.
• Spaghetti is bland? You were meant to eat
bland food.
• Car won’t work? Gods must be angry.
• Spaghetti is bland? At the instant of
tasting, tongue is transported to alternate
dimension where all flavors are rendered
nullified. Happens instantaneously.
Non-scientific Theories
• The chain of events needed for life to arise is
too complicated to have happened by
chance, a divine intelligence must therefore
have caused life to arise (Intelligent Design).
• Face on Mars.
Viking Orbiter (1976) Mars Global Surveyor (1998)
Falsification
• A real Scientific Theory tells you what
observations are necessary to falsify it.
– Not so proponents of:
• Face on Mars
• Moon Hoax
• Intelligent Design
• Astrologers
Astrology Tests
• What test would falsify astrology?
Astrology and the President
(TIME, May 16, House
“[Former White1988) -- Chief of Staff, Donald] Regan and
“The make a dabbled in case that in 1986 and 1987
othersFirst Ladycompellingastrology as far
back as 1967. In 1981 dramatically made
astrological influence [Joan] Quigleyreduced the
Nancy a believer …. And from then on, no
effectiveness, at was partly,
presidency'spublic appearance leastslated by keeping
presidential
Ronald Reagan under wraps for much of the time.
without the Friend's say-so. To this day,
Nancy's Friend continues scheduling process, Regan said
Nancy's intrusions in the to influence the
in an interview with TIME last week, „began to interfere
President's schedule. For the Reagan-
Gorbachev Washington summit, presidency.‟”
with the normal conduct of the she cast
the charts of both men and determined
that 2 p.m. on Dec. 8, 1987, was the most propitious moment
(TIME, May 16, 1988)
for them to sign the intermediate-range nuclear forces treaty.
At Nancy's behest, the entire summit was built around that
hour. For the upcoming Moscow summit, Gorbachev's chart
(he is a Pisces) has been recast alongside Reagan's
(Aquarius).”
HW#3
• Devise a scientific test for some
pseudoscience (astrology, tarot, etc).
– What claim are you testing?
– How will you test it?
• Due Tuesday 16th.