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Scientific Method
• Bacon (1561-1626) and Descartes (1596-1650)
– were not scientists but did invent new habits of
scientific thought
• scientific method as habits of disciplined creativity, careful
observations, logical thinking & analysis of observations
• way of seeking trends & drawing generalizations
• Convinced governments of England & France to
form academies of science that still exist today
• Scientific way of thinking based on assumptions
& methods that are reliable, objective & testable
Making observations until
capable of drawing
generalizations and making
predictions
– anatomy is a product of
inductive method
• Proof in science can not go
past “proved beyond
reasonable doubt”
– reliable methods of
observation
– tested and confirmed
repeatedly
– not falsified by any
credible observation
• In science, all truth is tentative
Inductive
Method
Hypothetico-Deductive Method
• Physiological knowledge
gained by this method
• Ask a question and formulate
a hypothesis -- an educated
possible answer
• Good hypothesis
– consistent with what is already
known
– capable of being tested and
falsified with certain evidence
• If nothing could prove it
wrong, it is not a scientific
belief
• Hypotheses are written as IfThen predictions
– modified and rewritten after
testing
Experimental Design
• Sufficient sample size to prevent chance event
• Control group and treatment group receive the same
treatment except for the variable being tested
• Prevention of psychosomatic effects
– use of placebo in control group
• Experimenter bias
– prevented with double-blind study
• Statistical testing to be sure the difference between
groups was not random, but was due to variable
being tested
Peer Review
• Critical evaluation by
other experts in the
field
– prior to funding
– verification and
repeatability of results
• Ensures honesty,
objectivity & quality in
science
Health Minister Manto Tshabalala-Msimang of South Africa, known for putting
vegetable remedies ahead of anti-retrovirals, endorses Dr Matthias Rath's vitamin
treatments.
Dr. Rath and his cure for AIDS: Mega
Doses of Vitamin C
• A doctor who worked
with Nobel Prize winner
Linus Pauling
• has taken the advocacy of
vitamins into all-out war on
the pharmaceutical companies
• Buys ad space in the NY
Times, and fills them with
editorials masked as facts
• Without getting confirmation
of his studies is taking his cure
to the people of Africa
• Problems: Too much Vitamin
C can lead to Diarrhea which
can kill an AIDS patient.
Facts, Laws and Theories
• Scientific fact is information that can be
independently verified by any trained person
– iron deficiency leads to anemia
• Law of nature is a description of the way matter
and energy behave
– resulting from inductive reasoning & repeated
observations
– written as verbal statements or mathematical formulae
• Theory is a summary of conclusions drawn from
observable facts
– it provides explanations and predictions
– sliding filament theory of muscle contraction
Logic is the anatomy of thought
-John Locke
• Conditional arguments: the
basis of hypothesis
forming. Two parts
• Part 1: If p then q
– P = antecedent
– Q = Consequent
• Part 2 allows us to draw
conclusions
– If P happens then Q happens
(Modus Ponens
– If Q did not happen, P did
not happen (Modus Tollens)
There is a claim that lycopene, the reddish substance in tomatoes and
peppers, is of value in protecting people from Alzheimer Disease. How
would you, as a scientist, go about substantiating or refuting this
suggestion?