Philosophy of Science: The Scientific Method

Transcription

1 Philosophy of Science: The Scientific Method Assoc. Prof. Dr. Jaafar Jantan aka DR. JJ Applied Science Education Research Applied Science, UiTM, Shah Alam Hiroshima Atomic Bomb The Mushroom, August 6 th 1945 Voice: drjjlanita@hotmail.com; jjnita@salam.uitm.edu.my Website: FSG500-Philosophy of Science Know Knowledge Facts Belief Truth How do you KNOW about. INQUIRE- find out What?? How?? Where?? When?? WHY?? Voice: fsg500@gmail.com; drjjlanita@hotmail.com; jjnita@salam.uitm.edu.my; ; Website: Background picture: The Death of Socrates as ordered by the court Copyrights DRJJ, UiTM

2 FSG500-Philosophy of Science Know Knowledge Facts Belief Truth How do you KNOW about. Methods of inquiry (source: Rae, 2010 Associated Content) Tenacity-prior belief or superstition; believing without question Authority-takes the word of another person (usually a reputable figure) without question Intuition-based on feeling (ESP??) Scientific-from questioning, observing, hypothesizing, experimenting, theorizing (empirical, objective & without bias via evidence) Voice: fsg500@gmail.com; drjjlanita@hotmail.com; jjnita@salam.uitm.edu.my; ; Website: Background picture: The Death of Socrates as ordered by the court FSG500-Philosophy of Science Time and space and gravitation have no separate existence from matter.... Physical objects are not in space, but these objects are spatially extended. In this way the concept 'empty space' loses its meaning.... The particle can only appear as a limited region in space in which the field strength or the energy density are particularly high.... Einstein summarizing theory of general relativity Science is but an image of the truth -Francis Bacon If a theory corresponds to the facts but does not cohere with some earlier knowledge, then this earlier knowledge should be discarded. (Popper, 1975) Voice: fsg500@gmail.com; drjjlanita@hotmail.com; jjnita@salam.uitm.edu.my; ; Website: Background picture: The Death of Socrates as ordered by the court Copyrights DRJJ, UiTM

3 FSG500-Philosophy of Science Karl Popper contended that central question in the philosophy of science was distinguishing science from non-science claimed that the central feature of science was that science aims at falsifiable claims (i.e. claims that can be proven false, at least in principle) Is human the result of intelligent design or a result of evolution? Are scientific theories the truth? Copernicus Heliocentric Sun-centered Theory Greece s Aristotle theory on gravity: all bodies had 'a natural tendency' to move to their 'natural place' (water, air, fire, earth???) widely accepted though entirely unproven explanation of gravity Voice: fsg500@gmail.com; drjjlanita@hotmail.com; jjnita@salam.uitm.edu.my; ; Website: Background picture: The Death of Socrates as ordered by the court Learning Objectives/Intended Learning Outcome: At the end of this session, participants should be able to: 1. Describe the meaning of science 2. Outline the scientific methods. 3. Discuss each stage of the method 4. Discuss the meaning of science, philosophy of science and explain the scientific methods. 5. Provide examples for each of the stage 6. Use the methods in a daily context. Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

4 Philosophy- Epistemology Epistemology is the study of our method of acquiring knowledge. It answers the question, "How do we know?" It encompasses the nature of concepts, the constructing of concepts, the validity of the senses, logical reasoning, as well as thoughts, ideas, memories, emotions, and all things mental. It is concerned with how our minds are related to reality, and whether these relationships are valid or invalid Epistemology is the explanation of how we think. It is required in order to be able to determine the true from the false, by determining a proper method of evaluation. It is needed in order to use and obtain knowledge of the world around us. Copyright DRJJ, ASERG, FSG, UiTM, Philosophy - Epistemology 1. Our senses are valid, and the only way to gain information about the world. 2. Reason is our method of gaining knowledge, and acquiring understanding. 3. Logic is our method of maintaining consistency within our set of knowledge. 4. Objectivity is our means of associating knowledge with reality to determine its validity. 5. Concepts are abstracts of specific details of reality, or of other abstractions. A proper epistemology is a rational epistemology Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

5 Philosophy - Epistemology Reason to know & understand How do we know?? Gain info or Experience through our senses Use logic for consistency Copyright DRJJ, ASERG, FSG, UiTM, Philosophy - Metaphysics Metaphysics is the branch of philosophy responsible for the study of existence. It is the foundation of a worldview. It answers the question "What is?" It encompasses everything that exists, as well as the nature of existence itself. It says whether the world is real, or merely an illusion. It is a fundamental view of the world around us Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

6 Philosophy - Metaphysics Metaphysics is the foundation of philosophy. Without an explanation or an interpretation of the world around us, we would be helpless to deal with reality. We could not feed ourselves, or act to preserve our lives. The degree to which our metaphysical worldview is correct is the degree to which we are able to comprehend the world, and act accordingly. Without this firm foundation, all knowledge becomes suspect. Any flaw in our view of reality will make it more difficult to live Copyright DRJJ, ASERG, FSG, UiTM, Philosophy - Metaphysics Reality is absolute. It has a specific nature independent of our thoughts or feelings. The world around us is real. It has a specific nature and it must be consistent to that nature. A proper metaphysical worldview must aim to understand reality correctly. The physical world exists, and every entity has a specific nature. It acts according to that nature. When different entities interact, they do so according to the nature of both. Every action has a cause and an effect. Causality is the means by which change occurs, but the change occurs via a specific nature. Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

7 What is Science?? Copyrights DRJJ, UiTM

8 What is Science?? Copyright DRJJ, ASERG, FSG, UiTM, Science Science, a method for problem solving & for describing how and why a natural event takes place. More importantly, it allows powerful prediction of events in the past & in the future Science & communication Science & health Science & entertainment Science & society Science & natural events August 6 and 9, 1945, the cities of Hiroshima and Nagasaki were destroyed by the first atomic bombs used in warfare. Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

9 Contemplate & reason to understand nature. Introduced observation as Method of investigation requiring: 1. defining the subject matter 2. considering the difficulties involved by reviewing the generally accepted views on the subject, and suggestions of earlier writers 3. presenting his own arguments and solutions. The arguments he used were of two types: dialectical, that is, based on logical deduction; and empirical, based on practical considerations. Leading to either absurdity or dilemma (resolved by removing ambiguity such as defining terms and concepts) Causes of nature: any object (animal, plant, inanimate, whatever) had four attributes: Entity Table man Matter wood Mother Form shape Rational 2-legged animal Moving Cause Carpenter father Final Cause (purpose) Studying, reading, eating Become a fully grown man Final cause is purpose i.e. meant to be: every organism is beautifully crafted for a particular function - its "final cause" - in the grand scheme of nature certainly leads naturally to the thought that all this has been designed by somebody Copyrights DRJJ, UiTM

10 Final Cause: Elements: Inanimate Aristotle assumed all substances to be compounds of four elements: earth, water, air and fire, and each of these to be a combination of two of four opposites, hot and cold, and wet and dry. Laws of motion Animal motion is directed by its will, fulfilling the "nature" of the animal, just as its natural growth fulfilled the nature of the animal. Inanimate objects (elements) tend to seek their natural place in the order of things. earth moves downwards most strongly water flows downwards too, but not so strongly, since a stone will fall through water air moves up (bubbles in water) and fire goes upwards most strongly of all, since it shoots upward through air wood, say, has both earth and air in it, since it does not sink in water Laws of motion A stone's natural tendency, if left alone and unsupported, is to fall, but we can lift it, or even throw it through the air. Aristotle termed such forced motion "violent" (presence of external force) motion as opposed to natural motion. Aristotle was the first to think quantitatively about the speeds involved in these movements. He asserted (state without evidence) that 1. Heavier things fall faster, the speed being proportional to the weight. (v fall α weight) 2. (v fall α 1/ρ ) (hence vacuum cannot exist since if it does then density is zero & speed of fall will be infinite & is totally absurd) 3. (v motion α F violent ). This means first that if you stop pushing, the object stops moving Question: : I am walking steadily upstairs carrying a large stone when I stumbled and both the stone and I go clattering down the stairs. Is the motion of the stone before the stumble natural or violent? What about the motion of the stone (and myself) after the stumble?) Copyrights DRJJ, UiTM

11 Modern Science Copernicus, Kepler, Galileo Newton "My God, what have we done?" - Robert Lewis, the co-pilot of the Enola Gay, the B-29 that dropped the first atomic bomb Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

12 The scientific method is a process for forming and testing solutions to problems, or theorizing about how or why things work. It tries to reduce the influence of "faith" or bias or prejudice of the experimenter so that the process is valid anywhere in our world. An hypothesis is a limited statement regarding cause and effect in specific situations; it also refers to our state of knowledge before experimental work has been performed and perhaps even before new phenomena have been predicted A model is reserved for situations when it is known that the hypothesis has at least limited validity. Bohr s atomic model, Hooke s law A scientific theory or law represents an hypothesis, or a group of related hypotheses, which has been confirmed (was not falsified) through repeated experimental tests A law is used with regularities which were discovered a long time ago while "theory" is applied to regularities discovered much more recently Copyrights DRJJ, UiTM

13 Scientific theories are: Consistent (internally and externally) Parsimonious or simple (sparing in proposed entities or explanations) Useful (describes and explains observed phenomena) Empirically Testable & Falsifiable Based upon Controlled, Repeated Experiments Correctable & Dynamic (changes are made as new data is discovered) Progressive (achieves all that previous theories have and more) Tentative and self correcting (admits that it might not be correct rather than asserting certainty) Noting facts Possible Explanation (testable) Observations Hypothesis Theory (Model) Until falsified Careful observation Generate Data (if results are repeatable, then explanation becomes a fact Experiment Law Prediction Experiment Modify Copyrights DRJJ, UiTM

14 Science There is a very important characteristic of a scientific theory or hypothesis which differentiates it from, for example, an act of faith: a theory must be ``falsifiable''. This means that there must be some experiment or possible discovery that could prove the theory untrue. For example, Einstein's theory of Relativity made predictions about the results of experiments. These experiments could have produced results that contradicted Einstein, so the theory was (and still is) falsifiable. 27 Copyrights DRJJ, UiTM

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18 What is truth? True" is defined as "consistent with fact or reality." So, something which is true always has been true, and always will be true. But is that really true? 1. The world was flat. 2. Earth is round. 3. Earth is slightly pear-shaped. 4. Compass needles pointed at the north star. 5. Earth was at the center of the universe, and that the sun traveled around the earth. 6. Blacks were inferior to whites. 7. Titanic is unsinkable. Einstein s s philosophical asymmetry explanation of the electromagnetic induction in his special relativity paper A fixed magnet produced current in the moving coil by an induced EMF in the coil. A moving magnet produced current in a fixed coil through the em field created by the moving magnet. So if the motion is relative why should there be any difference? Copyrights DRJJ, UiTM

19 Logic: A method to distinguish right from incorrect reasoning. Deduction is the use of known principles to formulate a hypothesis. (used by Aristotle) Conclusion MUST (used by Aristotle) Conclusion MUST FOLLOW necessarily from truth of ALL premises Argument #1 : Farah is over 90 years old. So Farah is over 20 years old. Argument #2 : Farah is over 20 years old. So Farah is over 90 years old. An argument is deductively valid if and only if there is no logically possible situation where all the premises are true and the conclusion is false at the same time Copyrights DRJJ, UiTM

20 Logic: A method to distinguish right from incorrect reasoning. Deduction is the use of known principles to formulate a hypothesis. (used by Aristotle) Conclusion MUST (used by Aristotle) Conclusion MUST FOLLOW necessarily from truth of ALL premises P1: Flowers are red P2: Tulips are flowers C: Hence Tulips are red P1: All men are immortal P2: Danial is a man C: Danial is immortal P1: All apples are fruit. P2: All fruits grow on trees. C: Therefore all apples grow on trees. Logic: A method to distinguish right from incorrect reasoning. Induction is the type of logic through which a person draws a conclusion from particular facts or individual observations. Conclusion follows but not necessarily, only probable Example: P 1 :This ice is cold. (or:p n All ice I have ever touched was cold.) C: All ice is cold. Copyrights DRJJ, UiTM

21 Logic: A method to distinguish right from incorrect reasoning. Induction is the type of logic through which a person draws a conclusion from particular facts or individual observations. Conclusion follows but not necessarily, only probable Example: P 1 : This billiard ball moves when struck with a cue. (or: P n : Of one hundred billiard balls struck with a cue, all of them moved.) C: All billiard balls move when struck with a cue. What is induction? Argument 1 (Valid or not Valid?) P: Dipsy bought one ticket in a fair lottery with ten million tickets. C: So Dipsy is not going to win the lottery. Argument 2 (Valid or not Valid?) P1: Dylan is a man. P2: He is 99 and is in a coma. C: Therefore, Dylan will not run in the marathon tomorrow. Inductively strong arguments Since premises are true, conclusion is highly likely Copyrights DRJJ, UiTM

22 Stages of Hypothetico-deductive method 1. Identify the hypothesis to be tested. 2. Generate predictions from the hypothesis. 3. Use experiments to check whether predictions are correct. 4. If the predictions are correct, then the hypothesis is confirmed.. If not, then the hypothesis is disconfirmed. A scientific hypothesis must be testable- The HD method tells us how to test a hypothesis, and a scientific hypothesis must be one that is capable of being tested. Confirmation is not truth In general, confirming the predictions of a theory increases the probability that a theory is correct. But in itself this does not prove conclusively that the theory is correct. Four components of Science Copyrights DRJJ, UiTM

23 What causes rain? Two people are asked to investigate this question. Observations: Both make the simple observation that rain is water which comes from the sky. Person 1 immediately hypothesizes that Rain is caused by angels crying (Hypothesis 1). Person 2 makes some other observations: 1) air contains a certain amount of moisture (she's tried to eat a salty pretzel in New York City on a humid day and watched the salt turn into a saline solution on the pretzel), and 2) air gets colder the higher up you go (she's climbed a mountain). Based on these two additional observations person 2 hypothesizes that moist air rises upward and cools, causing the water vapor to condense into drops, i.e., rain (hypothesis 2). What causes rain? Scientific method requires that these hypotheses be tested. H1: Rain is caused by angels crying : How will this be tested? Person 1 is in a bind. He can try to fly around in a rain storm and look for angels, or simply admit that his hypothesis is NON-TESTABLE, and therefore NOT scientific. (Scientific Method requires TESTABILITY). Copyrights DRJJ, UiTM

24 What causes rain? Scientific method requires that these hypotheses be tested. H2: moist air rises upward and cools, causing the water vapor to condense into drops, i.e., rain. Person 2, on the other hand, can perform a simple test. Experiment: She can take a piece of glass and put it into a dry freezer to make it very cold. On a humid day she can take it out and see if water condenses on the glass (since the environment in the freezer is dry any moisture which appears would have to come from the air). She can also run a simple experiment in the Spring or Fall to determine if dew comes from the air (this will probably require staying up all night). The point is that she or some other person can repeat this test (or similar tests) over and over and always come to the same conclusions. Her hypothesis will now be considered fact. Logic: A method to distinguish right from incorrect reasoning. Deduction is the use of known principles to formulate a hypothesis. If person 2 had simply stated that it is well known that water vapor condenses to liquid water when cooled, and that rain is probably caused by the cooling of moist air, she would have been using deductive reasoning. Note that, based upon a known principle she would have been predicting a result. In the rain example, person 2 demonstrated Induction by using her observations to formulate her hypothesis. Copyrights DRJJ, UiTM

25 Select the best answer, then provide your reasoning FCI25: A woman exerts a constant horizontal force on a large box. As a result, the box moves across a horizontal floor at a constant speed vo.. The constant horizontal force applied by the woman: a) has the same magnitude as the weight of the box. b) is greater than the weight of the box. c) has the same magnitude as the total force which resists the motion of the box. d) is greater than the total force which resists the motion of the box. e) is greater than either the weight of the box or the total force which resists its motion. Select the best answer, then provide your reasoning FCI 26: If the woman in the previous question doubles the constant horizontal force that she exerts on the box to push it on the same horizontal floor, the box then moves: a) with a constant speed that is double the speed v o in the previous question. b) with a constant speed that is greater than the speed v o in the previous question, but not necessarily twice as great. c) with a speed that is constant and greater than the speed v o in the previous question but later with a speed that increases thereafter. d) for a while with an increasing speed, then with a constant speed thereafter. e) with a continuously increasing speed. Copyrights DRJJ, UiTM

26 Select the best answer, then provide your reasoning A bulb and a battery are connected as shown below. Which of the following is true about the current at various point in the circuit A) The current is largest at A. B) The current is largest at B. C) The current is largest at C. D) The current is largest at D. E) The current is the same everywhere. F) The current is the same between A and B and smaller than between een C and D. G) The current is the same between A and B and larger than between en C and D. H) The current is the same everywhere except in the bulb. I) The current is the same everywhere except in the battery. J) None of these is true. Science Quantum theory, modern physical theory concerned with the emission and absorption of energy by matter and with the motion of material particles; the quantum theory and the theory of relativity together form the theoretical basis of modern physics. Just as the theory of relativity assumes importance in the special situation where very large speeds are involved, so the quantum theory is necessary for the special situation where very small quantities are involved, i.e., on the scale of molecules, atoms, and elementary particles. Aspects of the quantum theory have provoked vigorous philosophical debates concerning, for example, the uncertainty principle and the statistical nature of all the predictions of the theory. Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

27 Science In contrast, the theory that ``the moon is populated by little green men who can read our minds and will hide whenever anyone on Earth looks for them, and will flee into deep space whenever a spacecraft comes near'' is not falsifiable: these green men are designed so that no one can ever see them. On the other hand, the theory that there are no little green men on the moon is scientific: you can disprove it by catching one. Similar arguments apply to abominable snow-persons, UFOs and the Loch Ness Monster(s?).. Copyright DRJJ, ASERG, FSG, UiTM, Learning Science is a methodical approach to the acquisition of knowledge not the knowledge gained through the approach Method is based on evidence not belief Is not faith Atoms Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

28 Learning Observation Avoids sources of bias Quantify by making measurements Atoms Metric system-universal (measure & not convert) One basic unit & multipliers (prefixes) Time: Second Length: Meter: Inch, ft, yard, rod, mile..) Liter: drops, drams, fluid ounces, cups pints, quarts, gallons, barrel Gram: pounds, stone, Copyright DRJJ, ASERG, FSG, UiTM, Science Methods Question formulation Be curious & ask questions A stupid question is the question which you keep to yourself Science can answer some & not all questions Atoms Why am I here? purpose & begs answer from creator- faith Change to How do I get here? Which came first, chicken or egg Which came first, chicken egg or the chicken?? Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

29 Science Methods Hypothesis An educated guess to answer the question Suggest through literature review Must be rejectable Atoms Copyright DRJJ, ASERG, FSG, UiTM, Science Methods Prediction Formal test of the hypothesis Dependent variable (then) Independent variable (when) If-then-when Atoms Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

30 Science Methods Experiment Perform the manipulation Compare results to a control setting Many independent variables Atoms Copyright DRJJ, ASERG, FSG, UiTM, Science Methods Analysis Many trials Sources of error (false positive & false negative results) Statistical analysis (5% chance) Atoms Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM

31 Science Methods Decide Use error allowance of 5% to reject hypothesis Hypothesis are not proven (error chance is zero) ONLY disprove Many trials Examples Atoms Copyright DRJJ, ASERG, FSG, UiTM, the study of assumptions, foundations, and implications of science history of concepts and terms and how they are currently used in science the relation between propositions with arguments (Formal logic) the reasoning connecting hypotheses and conclusions (Scientific method) the manner in which science explains natural phenomena and predicts natural occurrences (observation) Copyrights DRJJ, UiTM

32 the types of reasoning that are used to arrive at scientific conclusions (deduction, induction, abduction) the formulation, scope, and limits of scientific understanding the means that should be used for determining when scientific information has adequate support (objectivity) and the implications of scientific methods and models, along with the technology that arises from scientific knowledge for the larger society (applied science) Composition Atoms Hysteria has hit students at Kenanga and Melati hostels. For the past 3 days at least 20 students in each hostel has been experiencing hysteria between 6-7pm. Authorities are puzzled and are trying to find out what causes the hysterical behaviour. Your help is needed. Propose 2 research questions and at least 2 hypothesis to answer each research question for the phenomena above Copyright DRJJ, ASERG, FSG, UiTM, Copyrights DRJJ, UiTM