Transcript Infectious diseases - University of Hong Kong

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Describe this picture?
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<Mother and Son>
Describe this picture?
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•
Observations are affected by one’s background
knowledge and what one wants to see
•
We can describe it as “observations are theory
laden”
Discussion:
In the following two slides we will look at how
different scientists came up with two different
claims for the pathogen causing SARS, try and
see if you notice some theory-laden observations.
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On March 18, 2003
Bernhard Nocht Institute,
Hamburg
Institute for Medical Virology,
Goethe University, Frankfurt
Paramyxovirus
CUHK
Pathology Department
Singapore General Hospital
National Microbiology Laboratory
Winnipeg
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Singapore’s Defence Medical
Research Institute
On March 21, 2003
Institute for Medical Virology
Goethe University, Frankfurt
HK Government
Virology Lab
Coronavirus
CDC
Atlanta, Georgia
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HKU
National Influenza Centre
Erasmus University, Rotterdam
Discussion Time
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Do you notice?

Once the possible pathogen causing SARS
was identified and announced, other groups
would quickly read of its existence

Their observations were biased by what they
were prepared to see or what other scientists
may have seen earlier
- Observations are theory laden 8
In the story of different scientists coming
up with two different claims for the
pathogen causing SARS, what else can
you say about the nature of science apart
from “Observations are theory laden”?
Hint: The identity of the SARS virus……?
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Got the answer already? If not, watch the
following video and think again.
Post-video discussion:
After scientists have developed a scientific
theory or a scientific law, does the theory/
law ever change? Why?
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Paramyxoviru
s
new evidence
Coronavirus
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Discussion Time
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Scientific knowledge changes or evolves
due to:
-
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New discoveries
Advances in technology
New ways of looking at existing
evidence
How about the story of a recent Nobel
prize winner – Dr. Barry Marshall
For many years, doctors thought that stomach
ulcers were a lifestyle disease. It was said to
be stress that caused excessive secretion of
acid in the stomach.
However, Dr. Barry Marshall suspected that the
bacteria he found in patients’ stomachs might
be causing the ulcers.
Homework: How would you get evidence for Dr.
Marshall’s hypothesis?
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How can there be
so many bacteria
in such an acid
environment?
Medicine can only relieve
your pain, it can’t cure
stomach ulcer.
Perhaps over secretion
of gastric juice is
caused by bacteria and
not stress.
This antibiotic
should work.
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The story of stomach ulcers
Great! The
antibiotic can cure
gastric ulcer. My
theory is right!
Discussion( Extension Activity )
It took more than 10 years for Marshall’s
ideas about the role of bacteria in
formation of ulcers to be generally
accepted! Why? Check it out on internet!
What elements of the nature of science can
you find in Dr. Marshall’s story?
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Summary
What have you learnt about the nature of science?
Scientists aim to be objective, however
observations are theory-laden
Scientific knowledge is tentative
It changes due to new evidence and new ways
of looking at existing evidence
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Acknowledgements
Prof. Dennis Lo
Department of Chemical Pathology,
Faculty of Medicine,
The Chinese University of Hong Kong
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