TOK II – Areas TOK II – Areas of Knowledge -of Knowledge -

The Natural The Natural Sciences – Part ISciences – Part I

Discussion QuestionsDiscussion Questions Is science the only road to Is science the only road to

knowledge?knowledge? Does science have a Does science have a

monopoly on truth?monopoly on truth? How far do the natural How far do the natural

sciences give us certainty?sciences give us certainty?

The Natural SciencesThe Natural Sciences Scientific Revolution – 17Scientific Revolution – 17thth

CenturyCentury Galileo GalileiGalileo Galilei Sir Issac NewtonSir Issac Newton

Discoveries of the Past 300 YearsDiscoveries of the Past 300 Years Fundamental laws of physicsFundamental laws of physics 92 Elements of the Periodic Table92 Elements of the Periodic Table DNA DecodingDNA Decoding

Natural SciencesNatural SciencesNatural Sciences Natural Sciences include:include:PhysicsPhysicsChemistryChemistryBiologyBiology

The Natural SciencesThe Natural Sciences Some argue that science is the only Some argue that science is the only

road to knowledgeroad to knowledge Natural Sciences are the Natural Sciences are the dominant dominant

cognitive paradigmcognitive paradigm (model of (model of knowledge)knowledge)

Science is not God and has Science is not God and has weaknesses and limitationsweaknesses and limitations

Scientific beliefs change over time.Scientific beliefs change over time.

Discussion QuestionsDiscussion Questions Give some examples of Give some examples of

things that were believed things that were believed to be true by 19to be true by 19thth century century scientists but which we scientists but which we now know to be false.now know to be false.

Are scientists playing God? Are scientists playing God? How?How?

Discussion QuestionsDiscussion Questions What connotations does the What connotations does the

word science have for you? Are word science have for you? Are they positive, negative, or they positive, negative, or mixed?mixed?

How are scientists viewed in How are scientists viewed in popular culture, such as novels popular culture, such as novels and movies? Are they generally and movies? Are they generally seen as heroes or as villains?seen as heroes or as villains?

Natural SciencesNatural Sciences How have advertisers used How have advertisers used

the the language of sciencelanguage of science to to market products?market products?

Science & MarketingScience & Marketing

Science vs. Pseudo-ScienceScience vs. Pseudo-Science All of the following have been described All of the following have been described

as scientific:as scientific: Acupuncture – needles & pinsAcupuncture – needles & pins Astrology – the starsAstrology – the stars Creationism – intelligent designCreationism – intelligent design Crystology – rocks that healCrystology – rocks that heal Feng shui – flow by organizationFeng shui – flow by organization Graphology - handwritingGraphology - handwriting Homeopathy – natural herbsHomeopathy – natural herbs Phrenology – skull studyPhrenology – skull study

Pseudo-Science (Fake Pseudo-Science (Fake Science)Science)

Some people are willing to subject Some people are willing to subject their beliefs to scientific tests, their beliefs to scientific tests, others simply state their beliefs are others simply state their beliefs are scientific.scientific.

Racists often claim their beliefs on Racists often claim their beliefs on biological research.biological research.

Pseudo-science claims the status of Pseudo-science claims the status of science while lacking its substance.science while lacking its substance.

Discussion QuestionsDiscussion QuestionsWhat is the difference What is the difference between astronomy & between astronomy & astrology?astrology?

As a scientist, how would As a scientist, how would you go about trying to test you go about trying to test the claims of astrology?the claims of astrology?

Science & Pseudo-Science –Science & Pseudo-Science –The DifferencesThe Differences

The main difference is that scientific The main difference is that scientific hypotheses arehypotheses are testable testable – pseudo-– pseudo-science is not. science is not.

Two ways pseudo science is NOT Two ways pseudo science is NOT testable:testable: Vagueness Vagueness – a genuine scientific claim – a genuine scientific claim

needs some kind of criteria (preferable needs some kind of criteria (preferable measurable).measurable).

Ad hoc exceptionsAd hoc exceptions – a scientific hypothesis – a scientific hypothesis is general in nature – “All swans are white.” is general in nature – “All swans are white.”

Science & Pseudo-Science –Science & Pseudo-Science –The DifferencesThe Differences

It will be easy to test a hypothesis It will be easy to test a hypothesis if the following are true:if the following are true: It is clearly stated and makes It is clearly stated and makes

precise rather than vague precise rather than vague predictions.predictions.

It does not keep making It does not keep making ad hocad hoc exceptions when it comes across exceptions when it comes across counter-examples.counter-examples.

Discussion QuestionDiscussion Question Which of the following statements makes Which of the following statements makes

scientifically testable claims?scientifically testable claims? In 2010 you may or may not win the lotteryIn 2010 you may or may not win the lottery It always rains on TuesdaysIt always rains on Tuesdays We have all lived past lives, but most of us We have all lived past lives, but most of us

are too unenlightened to remember themare too unenlightened to remember them Real men don’t cryReal men don’t cry Unlike magnetic poles attract each otherUnlike magnetic poles attract each other Everyone is selfishEveryone is selfish Acid turns litmus paper redAcid turns litmus paper red Something surprising will happen to you next Something surprising will happen to you next

weekweek

The Scientific MethodThe Scientific Method What distinguishes What distinguishes

science from non-science from non-science is a science is a distinctive method.distinctive method.

Science is not so Science is not so much a fixed body much a fixed body of knowledge as a of knowledge as a way of thinking way of thinking about the world.about the world.

Discussion QuestionDiscussion Question How is each of the following similar How is each of the following similar

to scientific activity and how is it to scientific activity and how is it different?different? Baking a cake by following a recipe.Baking a cake by following a recipe. ““Experimenting” with ingredients Experimenting” with ingredients

and making your own recipe.and making your own recipe. Collecting and organizing stamps Collecting and organizing stamps

from around the world.from around the world. Repairing a car that has broken Repairing a car that has broken

down.down.

InductivismInductivism InductivismInductivism is the traditional is the traditional

picture of the scientific method:picture of the scientific method: ObservationObservation HypothesisHypothesis ExperimentExperiment LawLaw TheoryTheory

InductivismInductivism 1) 1) ObservationObservation – observe and – observe and

classify dataclassify data 2) 2) HypothesisHypothesis – look for a pattern – look for a pattern

and make a guessand make a guess 3)3) Experiment Experiment – test the hypothesis– test the hypothesis

Controllability Controllability – vary only one factor – vary only one factor at a time to determine the effectat a time to determine the effect

MeasurabilityMeasurability – measure relevant – measure relevant variablesvariables

Repeatability Repeatability – experiement can be – experiement can be repeated with same results.repeated with same results.

Inductivism cont…Inductivism cont… 4) 4) LawLaw – if the experiment confirms – if the experiment confirms

the hypothesis and id is the hypothesis and id is controllable, measurable, and controllable, measurable, and repeatable.repeatable.

5) 5) TheoryTheory – explains and unifies – explains and unifies various laws and explains why laws various laws and explains why laws are the way they are and provides are the way they are and provides focus for further research.focus for further research.

The Copernican RevolutionThe Copernican Revolution Ptolemy (85-165) – Ptolemy (85-165) –

Earth centered theory Earth centered theory (geocentric)(geocentric)

Copernicus (1473-Copernicus (1473-1543) – Sun centered 1543) – Sun centered theory (heliocentric)theory (heliocentric)

How did each How did each develop their develop their theories?theories?

The Copernican RevolutionThe Copernican Revolution Observation:Observation: new and better new and better

observations made Ptolemy’s model observations made Ptolemy’s model more complicated.more complicated.

Hypothesis:Hypothesis: more elegant approach more elegant approach to make the sun the center.to make the sun the center.

Prediction:Prediction: Copernicus theorized Copernicus theorized that Venus becomes a different size that Venus becomes a different size through observations at different through observations at different times of year – Galileo (1564-1642) times of year – Galileo (1564-1642) confirmed this theory.confirmed this theory.

The Copernican RevolutionThe Copernican Revolution

Law:Law: Johannes Kepler (1571- Johannes Kepler (1571-1630) – developed laws of 1630) – developed laws of planetary motion based on planetary motion based on Copernicus and Galileo.Copernicus and Galileo.

Theory:Theory: Isaac Newton (1642- Isaac Newton (1642-1727) – theory of gravity allowed 1727) – theory of gravity allowed explanation of a wide variety of explanation of a wide variety of phenomenaphenomena

The Copernican RevolutionThe Copernican Revolution Newtonian physicsNewtonian physics – there is a force – there is a force

of attraction between objects whose of attraction between objects whose strength is directly proportional to strength is directly proportional to their masses and inversely their masses and inversely proportional to the square of the proportional to the square of the distance between them (if you double distance between them (if you double the distance between two objects, the the distance between two objects, the gravitational attraction between gravitational attraction between them will be ¼ of its original strength)them will be ¼ of its original strength)

The Copernican RevolutionThe Copernican Revolution

Newtonian physics thus Newtonian physics thus explains many things:explains many things: Why an apple falls from a treeWhy an apple falls from a tree Why people have weightWhy people have weight The movement of the tidesThe movement of the tides The orbit of the planetsThe orbit of the planets

The Copernican RevolutionThe Copernican Revolution The following points are taken from The following points are taken from

the Copernican Revolution:the Copernican Revolution: Scientific progress needs a background of Scientific progress needs a background of

careful observationcareful observation Technology can extend our powers of Technology can extend our powers of

observationobservation Imagination plays a role in the Imagination plays a role in the

development of new scientific ideasdevelopment of new scientific ideas Mathematics plays a central role in the Mathematics plays a central role in the

development of scientific ideas.development of scientific ideas. Many scientific discoveries are counter-Many scientific discoveries are counter-

intuitive – go against common sense.intuitive – go against common sense.

DiscussionDiscussion Try and explain the following to someone Try and explain the following to someone

who does not know much about physics:who does not know much about physics: If the earth is round and rotating on its If the earth is round and rotating on its

axis, how come it doesn’t feel like we axis, how come it doesn’t feel like we are moving?are moving?

If the Earth is round, why don’t people If the Earth is round, why don’t people fall off the bottom?fall off the bottom?

Since birds fly far slower than the Since birds fly far slower than the Earth rotates, how come they don’t get Earth rotates, how come they don’t get left behind when they fly in the left behind when they fly in the direction of the rotation (east to west)?direction of the rotation (east to west)?

Homework 1Homework 1Research the Research the placebo placebo effecteffect and give an and give an explanation of it. What explanation of it. What is its relevance when we is its relevance when we evaluate the claims of evaluate the claims of alternative medicinesalternative medicines??

Homework - 2Homework - 2 Each of the following elements below Each of the following elements below

is relevant to the scientific method. is relevant to the scientific method. Try to put them is sequential order Try to put them is sequential order and write a short description about and write a short description about how a scientist typically works.how a scientist typically works. Experiment, hypothesis, Experiment, hypothesis,

measurement, repeatability, measurement, repeatability, induction, law, observation, theory.induction, law, observation, theory.

TOK II – Areas TOK II – Areas of Knowledge -of Knowledge -

The Natural The Natural Sciences – Part IISciences – Part II

4 Problems with Observation4 Problems with Observation

RelevanceRelevance – you must begin with – you must begin with what is relevant and irrelevant to the what is relevant and irrelevant to the problem.problem.

ExpectationsExpectations – expectations can – expectations can influence what we seeinfluence what we see

Expert SeeingExpert Seeing – use of scientific – use of scientific equipment can often further equipment can often further complicate thingscomplicate things

The Observer EffectThe Observer Effect – the act can – the act can affect the outcome.affect the outcome.

Problems with ObservationProblems with Observation

RelevanceRelevance – it is always possible to – it is always possible to overlook a factoroverlook a factor

ExpectationsExpectations – overconfidence – overconfidence Expert SeeingExpert Seeing – observer is only as – observer is only as

good as their equipment.good as their equipment. The Observer EffectThe Observer Effect – the observer – the observer

changes the experiment – changes the experiment – thermometer in the hot tea.thermometer in the hot tea.

Complications of Testing Complications of Testing HypothesesHypotheses

Confirmation BiasConfirmation Bias – people look for – people look for evidence that confirms and ignore evidence that confirms and ignore what goes against them.what goes against them.

A good scientist is aware of A good scientist is aware of confirmation bias.confirmation bias.

Complications of Testing Complications of Testing HypothesesHypotheses

Background assumptionsBackground assumptions – we – we make assumptions that at any time make assumptions that at any time could be false. could be false.

Parallax – (ex. Stellar) relative Parallax – (ex. Stellar) relative position of stars changes as the earth position of stars changes as the earth moves around the sun.moves around the sun.

Complications of Testing Complications of Testing HypothesesHypotheses

Many different hypotheses are Many different hypotheses are consistent with a given set of data.consistent with a given set of data.

Principle of simplicity – when given Principle of simplicity – when given two complicated theories which two complicated theories which make exactly the same predictions make exactly the same predictions the simpler theory is to be preferred.the simpler theory is to be preferred.

The Problem of InductionThe Problem of Induction

Inductive reasoning goes Inductive reasoning goes from the particular to the from the particular to the general (all metals expand/all general (all metals expand/all mammals are warm blooded)mammals are warm blooded)

Practical ProblemsPractical Problems

How many observations should we How many observations should we make until we are entitled to make a make until we are entitled to make a generalization?generalization?

No “hard or fast rule about “how No “hard or fast rule about “how many?”many?”

We have observed a minute fraction We have observed a minute fraction of the universe, yet we apply the of the universe, yet we apply the laws we have learned to all of the laws we have learned to all of the universe.universe.

Theoretical ProblemsTheoretical Problems

Observation is supposed to be an Observation is supposed to be an empirical discipline which makes no empirical discipline which makes no claims past what is observed.claims past what is observed.

Observation is supposed to Observation is supposed to distinguish science from distinguish science from pseudoscience.pseudoscience.

FalsificationFalsification

Karl Popper (1902-1994) – tried to Karl Popper (1902-1994) – tried to distinguish science from distinguish science from pseudoscience pseudoscience (Marxism/psychoanalysis).(Marxism/psychoanalysis).

““A theory that explains everything A theory that explains everything explains nothing” – a scientific theory explains nothing” – a scientific theory must put itself at risk to be must put itself at risk to be disproven.disproven.

Conjectures & RefutationsConjectures & Refutations

A conjecture is basically an A conjecture is basically an imaginative hypothesis – no imaginative hypothesis – no mechanical way of coming up with mechanical way of coming up with good hypotheses on the basis of good hypotheses on the basis of observational data.observational data.

A scientific conjecture is testableA scientific conjecture is testable Refutation needs only find one Refutation needs only find one

instance to disprove a hypothesis.instance to disprove a hypothesis.

Conjectures & RefutationsConjectures & Refutations

Popper believed instead of trying to Popper believed instead of trying to prove something true, try to find prove something true, try to find faults instead.faults instead.

For science to progress it must For science to progress it must constantly question shortcomings.constantly question shortcomings.

Popper believed that an established Popper believed that an established theory is the theory is the bestbest we have for the we have for the time being.time being.

Criticisms of PopperCriticisms of Popper

Falsification Falsification Conclusive in theory but not in practiceConclusive in theory but not in practice No more conclusive than verificationNo more conclusive than verification Finding a single counter-example is not Finding a single counter-example is not

enough to overturn a law of nature.enough to overturn a law of nature. When a conflict occurs between When a conflict occurs between

hypothesis and observation we have a hypothesis and observation we have a choice to either reject the hypothesis, or choice to either reject the hypothesis, or we can reject the observation.we can reject the observation.

Examples of Refused abandoned Examples of Refused abandoned TheoriesTheories

Newton’s theory of gravity – gravity Newton’s theory of gravity – gravity would cause universe to crunchwould cause universe to crunch

Mendeleyev – some atomic weights Mendeleyev – some atomic weights did not quite fit his modeldid not quite fit his model

Darwin – Earth must be 100s of Darwin – Earth must be 100s of millions of years old to fit his theory millions of years old to fit his theory even though science at the time put even though science at the time put it about 100 million years old.it about 100 million years old.

Criticisms of PopperCriticisms of Popper

Auxiliary hypotheses can rescue Auxiliary hypotheses can rescue a falsified theorya falsified theory

Background assumptions could have Background assumptions could have been wrong or experimental error – been wrong or experimental error – hard to disprove hard factshard to disprove hard facts

No such thing as a perfect theory – No such thing as a perfect theory – auxiliary hypothesisauxiliary hypothesis..

Criticisms of PopperCriticisms of Popper

The rationalist strand in scientific The rationalist strand in scientific thinkingthinking When there is a conflict between observation When there is a conflict between observation

and hypothesis, there are 3 options:and hypothesis, there are 3 options: Reject the hypothesisReject the hypothesis Reject the observationReject the observation Accept both and form an auxiliary hypothesisAccept both and form an auxiliary hypothesis

A A rationalist rationalist sees reason as the main sees reason as the main source of knowledge – order to thingssource of knowledge – order to things

An An empiricist empiricist sees experience as the main sees experience as the main source of knowledge.source of knowledge.

SummarySummaryof Popper and Criticismsof Popper and Criticisms

Scientific theories can not be Scientific theories can not be conclusively verified because of the conclusively verified because of the problem of induction; and they problem of induction; and they cannot be conclusively verified cannot be conclusively verified because of the problem of induction.because of the problem of induction.

The concept of proof only applies to The concept of proof only applies to math and logic.math and logic.

Science cannot prove things in an Science cannot prove things in an absolute sense.absolute sense.

Thomas Kuhn (1922-1996)Thomas Kuhn (1922-1996)

Historian/Historian/Philosopher Philosopher of Scienceof Science

Introduce the Introduce the concept of concept of the the paradigmparadigm..

Science & Society According to Science & Society According to KuhnKuhn

Paradigm – an overarching theory Paradigm – an overarching theory shared by a community of scientists, shared by a community of scientists, such as physicists, chemists, or such as physicists, chemists, or biologists, which is used to make biologists, which is used to make sense of some aspect of reality.sense of some aspect of reality.

i.e. – Newtonian mechanics in i.e. – Newtonian mechanics in physics, Atomic theory in chemistry, physics, Atomic theory in chemistry, & Evolutionary theory in biology.& Evolutionary theory in biology.

Normal ScienceNormal Science

The vast majority of scientists are so The vast majority of scientists are so busy solving problems within a busy solving problems within a paradigm they take the actual paradigm they take the actual paradigm for granted.paradigm for granted.

A scientist cannot endlessly question A scientist cannot endlessly question assumptionsassumptions

Newton, Dalton, & Darwin were the Newton, Dalton, & Darwin were the architects – scientists today are the architects – scientists today are the bricklayers.bricklayers.

Scientific RevolutionsScientific Revolutions A scientific revolution takes place when A scientific revolution takes place when

scientists become dissatisfied with the scientists become dissatisfied with the prevailing paradigm, and put forward a prevailing paradigm, and put forward a completely new way of looking at things.completely new way of looking at things.

The new paradigm replaces the old and The new paradigm replaces the old and normal science begins again.normal science begins again.

Ex. Aristotelian Physics replaced Ex. Aristotelian Physics replaced Newtonian Mechanics (NM) and NM was Newtonian Mechanics (NM) and NM was replaced by Einstein’s Theory of Relativity.replaced by Einstein’s Theory of Relativity.

There is no such thing as a perfect theory There is no such thing as a perfect theory in science.in science.

..

How Rational is Science?How Rational is Science?

Progress of science is not as Progress of science is not as rational as sometimes thought.rational as sometimes thought.

Sometimes doubt and observations Sometimes doubt and observations that falsify old paradigms create that falsify old paradigms create irrational answers.irrational answers.

Priority Disputes – groundbreaking Priority Disputes – groundbreaking discoveries that set up paradigms discoveries that set up paradigms (scientists like (scientists like celebrity statuscelebrity status too!) too!)

Assessment of Kuhn – Normal Assessment of Kuhn – Normal ScienceScience

(1) During period of normal science, (1) During period of normal science, the paradigm is not questioned – the paradigm is not questioned – focus is on solving problems. (Popper focus is on solving problems. (Popper believed this was false and said that believed this was false and said that Kuhn was stagnating the science with Kuhn was stagnating the science with his approach)his approach)

Science should always question – one Science should always question – one should not be content to merely solve should not be content to merely solve puzzles.puzzles.

Assessment of Kuhn – Scientific Assessment of Kuhn – Scientific RevolutionsRevolutions

(2) History suggests science is not smooth (2) History suggests science is not smooth but rather makes revolutionary jumps.but rather makes revolutionary jumps.

This position could be false because This position could be false because science is punctuated with periods of science is punctuated with periods of intellectual upheaval.intellectual upheaval.

Intellectual upheaval does not mean when Intellectual upheaval does not mean when one paradigm replaces the old one that it one paradigm replaces the old one that it vanishes without a tracevanishes without a trace

Science progresses towards the Science progresses towards the truthtruth.. Science is a cumulative way to the future.Science is a cumulative way to the future.

Assessment of Kuhn – Choosing Assessment of Kuhn – Choosing Between Rival ParadigmsBetween Rival Paradigms

(3) During period of scientific crisis, (3) During period of scientific crisis, there is no purely rational way of there is no purely rational way of deciding between rival paradigms.deciding between rival paradigms.

We should choose between the We should choose between the origin of a belief and its justification.origin of a belief and its justification.

Origin of belief is of no great Origin of belief is of no great consequence.consequence.

All that matters is that a belief is All that matters is that a belief is testabletestable..

Assessment of Kuhn – Choosing Assessment of Kuhn – Choosing Between Rival ParadigmsBetween Rival Paradigms

Every area of knowledge depends on Every area of knowledge depends on judgment!judgment!

We need judgment to decide such We need judgment to decide such things as what factors should or things as what factors should or should not be observed, what can be should not be observed, what can be ignored, which hypotheses make ignored, which hypotheses make sense, what data should be used, sense, what data should be used, and what anomalies to take seriouslyand what anomalies to take seriously

Science & TruthScience & Truth

There is no absolute proof in There is no absolute proof in science.science.

We can neither conclusively We can neither conclusively verify or falsify a hypothesis.verify or falsify a hypothesis.

We must maintain a critical We must maintain a critical attitude to our scientific beliefs attitude to our scientific beliefs and be willing to question our and be willing to question our assumptions. assumptions.

A Theory of EverythingA Theory of Everything Some believe that the ultimate goal Some believe that the ultimate goal

of science is to discover a theory of science is to discover a theory that is so general that we have a that is so general that we have a complete understanding of nature.complete understanding of nature.

We will never know everything We will never know everything about nature – it is too complexabout nature – it is too complex

We will only be able to make We will only be able to make connections to nature and never connections to nature and never completely understand it.completely understand it.

Science & ScientismScience & Scientism

Science is the only way we can Science is the only way we can make sense of reality and make sense of reality and discover the truth.discover the truth.

We can be proud of science’s We can be proud of science’s achievements but it is a fallible achievements but it is a fallible human enterprise which may get human enterprise which may get us closer to the truth but never us closer to the truth but never give us certainty.give us certainty.

ConclusionConclusion

Science has been responsible for a Science has been responsible for a large body of knowledge in the past large body of knowledge in the past 300 years.300 years.

Science is limited to our Science is limited to our understanding of our world around us.understanding of our world around us.

Dogmatic scientism is static (Kuhn)Dogmatic scientism is static (Kuhn) Paradigm shifts occur with new Paradigm shifts occur with new

knowledge.knowledge.