IB Theory of Knowledge

1. Natural Science

2. What is Science?
• ‘Science’ can be defined simply as a methodology of
testing knowledge claims through empirical
observation (experimentation)
– Hypothesis
– Experimentation
– Analysis of results
– Develop scientific laws
– Develop scientific theories
– Repeat the cycle
• This is integrated with publication, peer review,
replication and falsification
‘science’ is therefore not really just a body of knowledge, as is commonly thought

3. The Scientific Method
Law
Hypothesis (must be falsifiable)
Experiment (with independent,
dependent and control variables)
Conclusion
Theory
Peer review,
replication of
experiments,
scrutiny by the
scientific
community
and attempts
at falsification
A paradigm
shift may (but
not always)
lead to
changes in
scientific laws

4. The Scientific Method
• The scientific method is a fairly simple idea
• But it took us over 2000 years to perfect it
• In fact, the last piece was only added in the 1960s
when Karl Popper (1902-1994) proposed the
principle of falsification

5. The Scientific Method
• The principle of falsification dictates that a scientist should abandon a
theory when it is falsified
• Sometime this doesn’t happen - it may be difficult for a scientist to admit
their (lifetime’s?) work is incorrect
• However the falsification itself may be incorrect (or limited by available
information):
– When Newton was asked why gravity did not cause the Universe to collapse he
stated that God was counteracting it (we now know the Universe is actually
expanding, overcoming gravitational attraction between galaxies)
– When Mendeleev saw that some atomic masses did not fit into his periodic
table, he concluded that experimental error was to blame (it was actually due to
the occurrence of isotopes)
– Lord Kelvin had measured the rate of cooling of the Earth and concluded
(incorrectly) that the Earth was approximately 100 million years old. When
Darwin realised this would mean the Earth was too young to support his theory
of evolution by natural selection, he merely stated that Kelvin was wrong
Therefore, is there a level of subjectivity to the Popper’s principle of falsification?

6. What is Pseudoscience
• When a knowledge claim purports to be scientific but does not
meet the requirements of the scientific method, we label it
pseudoscience
• Such claims are often falsifiable or make such vague claims that
they cannot be falsified (often supporters simply reject any
falsification)
• They are often based on belief systems which are not supported by
empirical observation
• While a good scientist (hopefully) should reject a hypothesis if it is
falsified, a pseudoscientist will often introduce ad hoc exceptions to
avoid doing so
http://edrontheoryofknowledge.blogspot.mx/2013/12/the-difference-between-quantum.html

8. However, just because something is not scientific does not mean it is
automatically pseudoscientific. A pseudoscience claims to be scientific when
it is not

9. A Scientific Knowledge Claim
Is this scientific?

10. Two Different Ideas
• The Story of
Creation in
Genesis
• Darwin’s Theory of
Evolution by
Natural Selection
Which is scientific and why?

11. Pseudoscience or science?
• Acupuncture
• Astrology
• Intelligent design
• Crystology
• Feng shui
• Graphology
• Homeopathy
• Phrenology
If it works for people, why
bother about whether it is
scientific or not?
But if it works then surely we
should find out WHY. Won’t
this then involve a scientific
hypothesis and testing and
therefore make it scientific?
Can something be unscientific
but NOT pseudoscience
Can something that has been
regarded as pseudoscience
become accepted as science?

12. Science
• Name as many sciences as possible
• What do they have in common?
• Science is thought of as being based on inductive logic
(observing the general and moving towards the specific) –
in other words, it is knowledge through verification
• However, in his essay ‘Science as Falsification’ Karl Popper
showed that scientific conclusions are reached via
falsification rather than verification
• Therefore the scientific method is not entirely inductive

13. The Problems of Science
• Since science is based on empirical observation, it is affected by the
problems that beset observation:
– Sometimes your expectations can lead you to see things that are not really
there. e.g. Planet Vulcan
– Acceptance of expert opinion or a fixed idea can lead you to not see (or
overlook) things that are really there. e.g. in May 1952 (a year before Watson
and Crick made their model) Rosalind Franklin had all the evidence she
needed to conclude that DNA was a double helix, but she didn’t interpret the
information correctly
– The act of observation itself has an effect on results (the observer effect). e.g.
placing a thermometer in a liquid affects the temperature of the liquid
– There are some things that the human brain doesn’t seem to be able to
understand (or things that lie outside our experience). e.g. The Bell
Experiment

14. Rationalism vs. Empiricism
• Rationalists look to reason to support knowledge claims while empiricists embrace
experience (observation)
• You might think this is the same thing, but while a rationalist would support a
beautiful theory over observational evidence, an empiricist would support the
observation over the theory (falsification)
• The correct stance in terms of the scientific method is really to be empirical.
Reason is limited by unconscious prejudices (although you could argue that our
sense perception has similar problems)
• In practice, science progresses through an uneasy mixture of rationalism and
empiricism
• This introduces problems into our idea of falsification. While a scientific theory can
never be proved (certainly not in the same way as a mathematical theorem),
perhaps it may not be possible to properly falsify either. However, be careful not to
equate this to relativism
Perhaps Newton, Mendeleev, Darwin and Einstein were rationalists rather than empiricists. When
Einstein was asked what he would have felt if Eddington’s observations had failed to support his
Theory of General Relativity, he said “Then I would feel sorry for the Good Lord. The theory is
correct.” (Einstein was, after all, an ‘armchair theorist’)

15. The Nature of Scientific Discovery
• Paradigm ‘A framework of belief, usually applied to ruling
theories of science’
• Paradigm shift ‘A complete change from one paradigm to
another, due to a major change in scientific thinking’
• The term was first used by philosopher Thomas Kuhn in his
book ‘The Structure of Scientific Revolutions’ (1962)
• Kuhn used the duck/rabbit illusion to
show how a paradigm shift could lead
to you seeing the same information in
a completely different way

16. Examples of Paradigm Shifts in Science
• The Copernican Revolution
• The replacement of phlogiston theory with Lavoisier’s ideas
of chemical reactions (‘The Chemical Revolution’)
• The publication of On The Origin of Species by Charles
Darwin
• The acceptance of Mendelian inheritance rather than
Darwin’s idea of ‘pangenesis’ (the idea that all of the
characteristics of a parent are heritable)
• From Newton’s idea of gravity to Einstein’s view of relativity
• Publication of Heisenberg’s Uncertainty Principle
• The elucidation of the structure and function of DNA
Note that paradigms exist in all areas of knowledge, not just natural science
We associate paradigm shifts with the idea of ‘genius’
Note that the IB does not like you to use clichéd examples of paradigms in your essay

17. Recognising a Paradigm Shift
• Sometimes a paradigm shift occurs very suddenly – e.g. Sir
Arthur Eddington proved Einstein’s Theory of General
Relativity correct by observing a solar eclipse on 29th May
1919
• Sometimes it takes time for scientists to recognise a
paradigm shift. Thomas Kuhn likened this to religious
conversion
• Sometimes claims are made for a paradigm shift which the
scientific community rejects. e.g. homeopathists claim that
their remedies work because water molecules have a
‘memory’ of a cure and pass this on to their patients. This
would require a new paradigm in chemistry and biology to
be correct

18. Reaction to Paradigm shifts
• Reaction to a paradigm shift can be very negative, sometimes violent and
sometimes very long-lasting (often in opposition to the scientific evidence)
• e.g. The Catholic Church condemned Copernicus and imprisoned Galileo
• e.g. There is widespread opposition to the teaching of evolution in schools
• On 31 October 1992, Pope John Paul II
expressed regret for how the Galileo
affair was handled, and officially
conceded that the Earth was not
stationary, following a study conducted
by the Pontifical Council for Culture
(Galileo was kept under house arrest by
the Church from 1633 until his death in
1642)
• On 15 February 1990, in a speech
delivered at the University of Rome,
Cardinal Ratzinger cited current views
on the Galileo affair as forming what he
called "a symptomatic case that
permits us to see how deep the self-
doubt of the modern age, of science
and technology goes today“
• He stated that the treatment of Galileo
by the Inquisition was “rational” and
“just”

19. Progress in Science
• Kuhn claimed that progress in science is punctuated -
i.e. there are periods of crisis which result in scientific
revolutions
• He stated there are periods where paradigms exist together
and scientists must choose between them. At other times
scientists simply work within the existing paradigm without
even questioning it
• Popper felt that scientific progress was much smoother
with new paradigms being accepted much more easily into
the body of scientific knowledge
Interestingly, a similar argument exists in evolutionary biology - Stephen Jay Gould developed a
theory of punctuated equilibrium in which evolution occurs in marked jumps. Richard Dawkins
believes gaps in the fossil record which support this are due to migration events

20. Reductionism
• Reductionism is an approach to building descriptions of
systems out of the descriptions of the sub-systems that they
are composed of
• Biology: atoms form molecules form organelles form cells
form tissues form organs form organ systems form bodies
form species form communities ….and so on
• Physics: atoms form molecules form minerals form rocks form
planets form solar systems form galaxies… and so on
• The idea is that if we fully understand atoms we can
understand basic systems, and then we can understand the
systems that are formed from them

21. Chaos Theory
• In mathematics and science, chaos theory describes the behavior of
certain systems which evolve with time – these may be highly
sensitive to initial conditions (popularly referred to as the butterfly
effect)
• This occurs due to the exponential growth of perturbations in the
initial conditions and the behavior of chaotic systems appears to be
random
• This happens even though chaotic systems are deterministic (their
future dynamics are fully defined by their initial conditions with no
random elements involved)
• Chaotic behavior is also observed in natural systems, such as the
weather, and mathematical patterns such as fractals
http://edrontheoryofknowledge.blogspot.mx/2012/11/chaos-theory-and-butterfly-effect.html

22. Emergence
• The observation that from chaotic behaviour,
order can spontaneously arise. Examples
include hive behaviour of insects, schooling of
fish, flocking of birds and even the predictable
movements of a crowd of people
http://edrontheoryofknowledge.blogspot.mx/2014/08/emergent-behaviour.html
http://edrontheoryofknowledge.blogspot.mx/2009/05/what-are-emergent-properties.html

23. The Game of Life
• The Game of Life is a computer simulation devised in the
1960's by the mathematician John Horton Conway. It's a very
good example of how a few simple rules can quickly create
order out of chaos, resulting in emergent behaviour. The
simulation takes place on a 2-dimensional grid divided into
cells. Each cell has eight neighbouring cells and can be either
"alive" or "dead". The rules which determine it's fate are very
simple:
• 1. If a cell has one or no living neighbours, it will die of
loneliness.
2. If it has too many neighbours - four or more - it will die from
overcrowding.
3. New cells are "born" whenever an empty square has exactly
three living neighbours.
http://edrontheoryofknowledge.blogspot.mx/2009/05/the-game-of-life.html

24. Science and Truth
• Science is a tool for getting closer to the truth
• There are problems involved in falsification and a scientific theory by
definition can never be claimed as fact (some people think the use of the
word ‘theory’ in science equates to a lack of certainty)
• However, perhaps paradoxically it is the best method we have for
approaching truth about our observations of the Universe around us
• If a scientific theory has supporting evidence, corresponds to previous
knowledge, coheres to the current paradigm and is pragmatic then we can
accept it as true (at least until a better version of the theory comes along
or there is a paradigm shift)
“Science does not aim at establishing immutable truths and eternal dogmas;
its aim is to approach the truth by successive approximations, without
claiming that at any stage final and complete accuracy has been achieved.”
- Bertrand Russell