TOK II – Areas of Knowledge - The Natural Sciences – Part I

Discussion Questions Is science the only road to knowledge? Does science have a monopoly on truth? How far do the natural sciences give us certainty?

The Natural Sciences Scientific Revolution – 17th Century Galileo Galilei Sir Issac Newton Discoveries of the Past 300 Years Fundamental laws of physics 92 Elements of the Periodic Table DNA Decoding

Natural Sciences Natural Sciences include: Physics Chemistry Biology

The Natural Sciences Some argue that science is the only road to knowledge Natural Sciences are the dominant cognitive paradigm (model of knowledge) Science is not God and has weaknesses and limitations Scientific beliefs change over time.

Discussion Questions Give 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?

Discussion Questions What 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?

Natural Sciences How have advertisers used the language of science to market products?

Science & Marketing

Science vs. Pseudo-Science All of the following have been described as scientific: Acupuncture – needles & pins Astrology – the stars Creationism – intelligent design Crystology – rocks that heal Feng shui – flow by organization Graphology - handwriting Homeopathy – natural herbs Phrenology – skull study

Pseudo-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.

Discussion Questions What is the difference between astronomy & astrology? As a scientist, how would you go about trying to test the claims of astrology?

Science & 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.”

Science & 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.

Discussion Question Which of the following statements makes scientifically testable claims? In 2010 you may or may not win the lottery It always rains on Tuesdays We have all lived past lives, but most of us are too unenlightened to remember them Real men don’t cry Unlike magnetic poles attract each other Everyone is selfish Acid turns litmus paper red Something surprising will happen to you next week

The Scientific Method What 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.

Discussion Question How 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.

Inductivism Inductivism is the traditional picture of the scientific method: Observation Hypothesis Experiment Law Theory

Inductivism 1) Observation – observe and classify data 2) Hypothesis – look for a pattern and make a guess 3) Experiment – test the hypothesis Controllability – vary only one factor at a time to determine the effect Measurability – measure relevant variables Repeatability – experiement can be repeated with same results.

Inductivism 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.

The Copernican Revolution Ptolemy (85-165) – Earth centered theory (geocentric) Copernicus (1473-1543) – Sun centered theory (heliocentric) How did each develop their theories?

The 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 (1564-1642) confirmed this theory.

The Copernican Revolution Law: Johannes Kepler (1571-1630) – developed laws of planetary motion based on Copernicus and Galileo. Theory: Isaac Newton (1642-1727) – theory of gravity allowed explanation of a wide variety of phenomena

The 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)

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

The Copernican Revolution The following points are taken from the Copernican Revolution: Scientific progress needs a background of careful observation Technology can extend our powers of observation Imagination plays a role in the development of new scientific ideas Mathematics plays a central role in the development of scientific ideas. Many scientific discoveries are counter-intuitive – go against common sense.

Discussion Try 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)?

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

Homework - 2 Each 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.

TOK II – Areas of Knowledge - The Natural Sciences – Part II

4 Problems with Observation Relevance – you must begin with what is relevant and irrelevant to the problem. Expectations – expectations can influence what we see Expert Seeing – use of scientific equipment can often further complicate things The Observer Effect – the act can affect the outcome.

Problems with Observation Relevance – it is always possible to overlook a factor Expectations – overconfidence Expert Seeing – observer is only as good as their equipment. The Observer Effect – the observer changes the experiment – thermometer in the hot tea.

Complications 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.

Complications 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.

Complications 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.

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

Practical Problems How 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.

Theoretical Problems Observation is supposed to be an empirical discipline which makes no claims past what is observed. Observation is supposed to distinguish science from pseudoscience.

Falsification Karl Popper (1902-1994) – 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.

Conjectures & 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 testable Refutation needs only find one instance to disprove a hypothesis.

Conjectures & 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.

Criticisms of Popper Falsification Conclusive in theory but not in practice No more conclusive than verification Finding 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.

Examples of Refused abandoned Theories Newton’s theory of gravity – gravity would cause universe to crunch Mendeleyev – some atomic weights did not quite fit his model Darwin – 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.

Criticisms of Popper Auxiliary hypotheses can rescue a falsified theory Background assumptions could have been wrong or experimental error – hard to disprove hard facts No such thing as a perfect theory – auxiliary hypothesis.

Criticisms of Popper The rationalist strand in scientific thinking When there is a conflict between observation and hypothesis, there are 3 options: Reject the hypothesis Reject the observation Accept both and form an auxiliary hypothesis A rationalist sees reason as the main source of knowledge – order to things An empiricist sees experience as the main source of knowledge.

Summary 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.

Historian/Philosopher of Science Thomas Kuhn (1922-1996) Historian/Philosopher of Science Introduce the concept of the paradigm.

Science & 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.

Normal Science The vast majority of scientists are so busy solving problems within a paradigm they take the actual paradigm for granted. A scientist cannot endlessly question assumptions Newton, Dalton, & Darwin were the architects – scientists today are the bricklayers.

Scientific 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. .

How 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!)

Assessment 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.

Assessment 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 trace Science progresses towards the truth. Science is a cumulative way to the future.

Assessment 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.

Assessment 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

Science & 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.

A Theory of Everything Some 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 complex We will only be able to make connections to nature and never completely understand it.

Science & Scientism Science 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.

Conclusion Science 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.