6The Natural SciencesSome argue that science is the only road to knowledgeNatural Sciences are the dominant cognitive paradigm (model of knowledge)Science is not God and has weaknesses and limitationsScientific beliefs change over time.
7Discussion QuestionsGive some examples of things that were believed to be true by 19th century scientists but which we now know to be false.Are scientists playing God? How?
8Discussion QuestionsWhat connotations does the word science have for you? Are they positive, negative, or mixed?How are scientists viewed in popular culture, such as novels and movies? Are they generally seen as heroes or as villains?
9Natural SciencesHow have advertisers used the language of science to market products?
11Science vs. Pseudo-Science All of the following have been described as scientific:Acupuncture – needles & pinsAstrology – the starsCreationism – intelligent designCrystology – rocks that healFeng shui – flow by organizationGraphology - handwritingHomeopathy – natural herbsPhrenology – skull study
12Pseudo-Science (Fake Science) Some people are willing to subject their beliefs to scientific tests, others simply state their beliefs are scientific.Racists often claim their beliefs on biological research.Pseudo-science claims the status of science while lacking its substance.
13Discussion QuestionsWhat is the difference between astronomy & astrology?As a scientist, how would you go about trying to test the claims of astrology?
14Science & Pseudo-Science – The Differences The main difference is that scientific hypotheses are testable – pseudo-science is not.Two ways pseudo science is NOT testable:Vagueness – a genuine scientific claim needs some kind of criteria (preferable measurable).Ad hoc exceptions – a scientific hypothesis is general in nature – “All swans are white.”
15Science & Pseudo-Science – The Differences It will be easy to test a hypothesis if the following are true:It is clearly stated and makes precise rather than vague predictions.It does not keep making ad hoc exceptions when it comes across counter-examples.
16Discussion QuestionWhich of the following statements makes scientifically testable claims?In 2010 you may or may not win the lotteryIt always rains on TuesdaysWe have all lived past lives, but most of us are too unenlightened to remember themReal men don’t cryUnlike magnetic poles attract each otherEveryone is selfishAcid turns litmus paper redSomething surprising will happen to you next week
17The Scientific MethodWhat distinguishes science from non-science is a distinctive method.Science is not so much a fixed body of knowledge as a way of thinking about the world.
18Discussion QuestionHow is each of the following similar to scientific activity and how is it different?Baking a cake by following a recipe.“Experimenting” with ingredients and making your own recipe.Collecting and organizing stamps from around the world.Repairing a car that has broken down.
19InductivismInductivism is the traditional picture of the scientific method:ObservationHypothesisExperimentLawTheory
20Inductivism 1) Observation – observe and classify data 2) Hypothesis – look for a pattern and make a guess3) Experiment – test the hypothesisControllability – vary only one factor at a time to determine the effectMeasurability – measure relevant variablesRepeatability – experiement can be repeated with same results.
21Inductivism cont…4) Law – if the experiment confirms the hypothesis and id is controllable, measurable, and repeatable.5) Theory – explains and unifies various laws and explains why laws are the way they are and provides focus for further research.
22The Copernican Revolution Ptolemy (85-165) – Earth centered theory (geocentric)Copernicus ( ) – Sun centered theory (heliocentric)How did each develop their theories?
23The Copernican Revolution Observation: new and better observations made Ptolemy’s model more complicated.Hypothesis: more elegant approach to make the sun the center.Prediction: Copernicus theorized that Venus becomes a different size through observations at different times of year – Galileo ( ) confirmed this theory.
24The Copernican Revolution Law: Johannes Kepler ( ) – developed laws of planetary motion based on Copernicus and Galileo.Theory: Isaac Newton ( ) – theory of gravity allowed explanation of a wide variety of phenomena
25The Copernican Revolution Newtonian physics – there is a force of attraction between objects whose strength is directly proportional to their masses and inversely proportional to the square of the distance between them (if you double the distance between two objects, the gravitational attraction between them will be ¼ of its original strength)
26The Copernican Revolution Newtonian physics thus explains many things:Why an apple falls from a treeWhy people have weightThe movement of the tidesThe orbit of the planets
27The Copernican Revolution The following points are taken from the Copernican Revolution:Scientific progress needs a background of careful observationTechnology can extend our powers of observationImagination plays a role in the development of new scientific ideasMathematics plays a central role in the development of scientific ideas.Many scientific discoveries are counter-intuitive – go against common sense.
28DiscussionTry and explain the following to someone who does not know much about physics:If the earth is round and rotating on its axis, how come it doesn’t feel like we are moving?If the Earth is round, why don’t people fall off the bottom?Since birds fly far slower than the Earth rotates, how come they don’t get left behind when they fly in the direction of the rotation (east to west)?
29Homework 1Research the placebo effect and give an explanation of it. What is its relevance when we evaluate the claims of alternative medicines?
30Homework - 2Each of the following elements below is relevant to the scientific method. Try to put them is sequential order and write a short description about how a scientist typically works.Experiment, hypothesis, measurement, repeatability, induction, law, observation, theory.
31TOK II – Areas of Knowledge - The Natural Sciences – Part II
324 Problems with Observation Relevance – you must begin with what is relevant and irrelevant to the problem.Expectations – expectations can influence what we seeExpert Seeing – use of scientific equipment can often further complicate thingsThe Observer Effect – the act can affect the outcome.
33Problems with Observation Relevance – it is always possible to overlook a factorExpectations – overconfidenceExpert Seeing – observer is only as good as their equipment.The Observer Effect – the observer changes the experiment – thermometer in the hot tea.
34Complications of Testing Hypotheses Confirmation Bias – people look for evidence that confirms and ignore what goes against them.A good scientist is aware of confirmation bias.
35Complications of Testing Hypotheses Background assumptions – we make assumptions that at any time could be false.Parallax – (ex. Stellar) relative position of stars changes as the earth moves around the sun.
36Complications of Testing Hypotheses Many different hypotheses are consistent with a given set of data.Principle of simplicity – when given two complicated theories which make exactly the same predictions the simpler theory is to be preferred.
37The Problem of Induction Inductive reasoning goes from the particular to the general (all metals expand/all mammals are warm blooded)
38Practical ProblemsHow many observations should we make until we are entitled to make a generalization?No “hard or fast rule about “how many?”We have observed a minute fraction of the universe, yet we apply the laws we have learned to all of the universe.
39Theoretical ProblemsObservation is supposed to be an empirical discipline which makes no claims past what is observed.Observation is supposed to distinguish science from pseudoscience.
40FalsificationKarl Popper ( ) – tried to distinguish science from pseudoscience (Marxism/psychoanalysis).“A theory that explains everything explains nothing” – a scientific theory must put itself at risk to be disproven.
41Conjectures & Refutations A conjecture is basically an imaginative hypothesis – no mechanical way of coming up with good hypotheses on the basis of observational data.A scientific conjecture is testableRefutation needs only find one instance to disprove a hypothesis.
42Conjectures & Refutations Popper believed instead of trying to prove something true, try to find faults instead.For science to progress it must constantly question shortcomings.Popper believed that an established theory is the best we have for the time being.
43Criticisms of Popper Falsification Conclusive in theory but not in practiceNo more conclusive than verificationFinding a single counter-example is not enough to overturn a law of nature.When a conflict occurs between hypothesis and observation we have a choice to either reject the hypothesis, or we can reject the observation.
44Examples of Refused abandoned Theories Newton’s theory of gravity – gravity would cause universe to crunchMendeleyev – some atomic weights did not quite fit his modelDarwin – Earth must be 100s of millions of years old to fit his theory even though science at the time put it about 100 million years old.
45Criticisms of PopperAuxiliary hypotheses can rescue a falsified theoryBackground assumptions could have been wrong or experimental error – hard to disprove hard factsNo such thing as a perfect theory – auxiliary hypothesis.
46Criticisms of Popper The rationalist strand in scientific thinking When there is a conflict between observation and hypothesis, there are 3 options:Reject the hypothesisReject the observationAccept both and form an auxiliary hypothesisA rationalist sees reason as the main source of knowledge – order to thingsAn empiricist sees experience as the main source of knowledge.
47Summary of Popper and Criticisms Scientific theories can not be conclusively verified because of the problem of induction; and they cannot be conclusively verified because of the problem of induction.The concept of proof only applies to math and logic.Science cannot prove things in an absolute sense.
48Historian/Philosopher of Science Thomas Kuhn ( )Historian/Philosopher of ScienceIntroduce the concept of the paradigm.
49Science & Society According to Kuhn Paradigm – an overarching theory shared by a community of scientists, such as physicists, chemists, or biologists, which is used to make sense of some aspect of reality.i.e. – Newtonian mechanics in physics, Atomic theory in chemistry, & Evolutionary theory in biology.
50Normal ScienceThe vast majority of scientists are so busy solving problems within a paradigm they take the actual paradigm for granted.A scientist cannot endlessly question assumptionsNewton, Dalton, & Darwin were the architects – scientists today are the bricklayers.
51Scientific Revolutions A scientific revolution takes place when scientists become dissatisfied with the prevailing paradigm, and put forward a completely new way of looking at things.The new paradigm replaces the old and normal science begins again.Ex. Aristotelian Physics replaced Newtonian Mechanics (NM) and NM was replaced by Einstein’s Theory of Relativity.There is no such thing as a perfect theory in science..
52How Rational is Science? Progress of science is not as rational as sometimes thought.Sometimes doubt and observations that falsify old paradigms create irrational answers.Priority Disputes – groundbreaking discoveries that set up paradigms (scientists like celebrity status too!)
53Assessment of Kuhn – Normal Science (1) During period of normal science, the paradigm is not questioned – focus is on solving problems. (Popper believed this was false and said that Kuhn was stagnating the science with his approach)Science should always question – one should not be content to merely solve puzzles.
54Assessment of Kuhn – Scientific Revolutions (2) History suggests science is not smooth but rather makes revolutionary jumps.This position could be false because science is punctuated with periods of intellectual upheaval.Intellectual upheaval does not mean when one paradigm replaces the old one that it vanishes without a traceScience progresses towards the truth.Science is a cumulative way to the future.
55Assessment of Kuhn – Choosing Between Rival Paradigms (3) During period of scientific crisis, there is no purely rational way of deciding between rival paradigms.We should choose between the origin of a belief and its justification.Origin of belief is of no great consequence.All that matters is that a belief is testable.
56Assessment of Kuhn – Choosing Between Rival Paradigms Every area of knowledge depends on judgment!We need judgment to decide such things as what factors should or should not be observed, what can be ignored, which hypotheses make sense, what data should be used, and what anomalies to take seriously
57Science & Truth There is no absolute proof in science. We can neither conclusively verify or falsify a hypothesis.We must maintain a critical attitude to our scientific beliefs and be willing to question our assumptions.
58A Theory of EverythingSome believe that the ultimate goal of science is to discover a theory that is so general that we have a complete understanding of nature.We will never know everything about nature – it is too complexWe will only be able to make connections to nature and never completely understand it.
59Science & ScientismScience is the only way we can make sense of reality and discover the truth.We can be proud of science’s achievements but it is a fallible human enterprise which may get us closer to the truth but never give us certainty.
60ConclusionScience has been responsible for a large body of knowledge in the past 300 years.Science is limited to our understanding of our world around us.Dogmatic scientism is static (Kuhn)Paradigm shifts occur with new knowledge.