110902 theory of science
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110902 theory of science Presentation Transcript

  • 1. Critical thinking Sapere Aude:Having determination and courageto think independently
  • 2. Scientific tools forindependent critical thinking
  • 3. Practical tools- Methodology and methods
  • 4. Theoretical tools- Philosophy and theory of science
  • 5. Positivism The idea (analysis based on observation) appears in Ibn al- Haythams 11th Century text “Book of Optics”Positivism - an approach to the philosophy of science, deriving from Enlightenment thinkers (Voltaire, Rossaueu, Kant) Logical positivism - a school of philosophy developed in the 1920s by the Vienna Circle (Moritz Schlick) Social positivism - in social sciences, an approach to understanding the world based on science (Auguste Comte) Postpositivism - a philosophical stance following positivism
  • 6. Positivism Positivism is a philosophy that states that the onlyauthentic knowledge is scientific knowledge, and that such knowledge can only come from positiveaffirmation of theories through strict scientific method. It was developed by Auguste Comte (1798 – 1857). He was a French thinker who coined the term "sociology." He is remembered for being the first to apply the scientific method to the social world.
  • 7. “The law of three stages”An idea developed by Auguste Comte. It states thatknowledge of any subject always begins in theologic form, passes to the metaphysical form, and finally becomes positive.The Theologic form refers to explanation by spirits,gods, etc.The Metaphysical form refers to explanation byabstract philosophical explanation.Positivity refers to scientific explanation based onobservation, experiment, and comparison.
  • 8. FalsificationismKarl Popper, a well-known critic of logical positivism,published the book Logik der Forschung in 1934In it he presented an influential alternative to theverifiability criterion of meaning, defining scientificstatements in terms of falsifiability.
  • 9. Some key features of modern positivism (sometimes referred to as “the received view of science”):A focus on science as a product, a linguistic or numerical setof statementsA concern with demonstrating the logical structure andcoherence of these statementsAn insistence on that statements should be testable, that isamenable to being verified, confirmed, or falsified by theempirical observation of reality;
  • 10. The belief that science is markedly cumulativeThe belief that science is transcultural;The belief that science rests on specific results that aredissociated from the personality and social position of theinvestigator;The belief that science contains theories or research traditionsthat are largely commensurable;The belief that science involves the idea of the unity ofscience, that there is, underlying the various scientificdisciplines, basically one logic of scientific inquiry about onereal world.
  • 11. Positivism- the goal of inquiry is to explain and predict.scientific knowledge is testable. research can beproved only by empirical means, not argumentations-science does not equal common sense. Researchersmust be careful not to let common sense bias theirresearch.- relation of theory to practice - science should be asvalue-free as possible, and the ultimate goal ofscience is to produce knowledge, regardless ofpolitics, morals, values, etc. involved in the research.
  • 12. Critique of PositivismInternal critiqueContext strippingExclusion of meaning and purposeEtic (outsider) / Emic (insider) dilemmaGeneral data vs. individual casesExclusion of discovery dimension (hyp-ded)
  • 13. Critique of PositivismExternal critiqueFacts impregnated by theory/ paradigm/ discourseUnderdetermination of theory(Facts are always open for different interpretations)Facts are impregnated by valuesFacts dependent on inquirer-inquired interaction
  • 14. HermeneuticsEssentially, hermeneutics involves cultivating theability to understand things from somebody elsespoint of view, and to appreciate the cultural andsocial forces that may have influenced their outlook.The word hermeneutics is a term derived fromΕρμηνεύς, (hermeneuo, translate or interpret‘),related to the name of the Greek god Hermes in hisrole as the interpreter of the messages of the gods.
  • 15. HermeneuticsHermeneutics in the Western world, as a general science oftext interpretation, can be traced back to two sources.One source was the ancient Greek rhetoricians study ofliterature, which came to fruition in Alexandria.The other source has been the traditions of Biblical exegesisThe discipline of hermeneutics emerged with the newhumanist education of the 15th century as a historical andcritical methodology for analyzing texts.Thus hermeneutics expanded from its medieval roleexplaining the correct analysis of the Bible.
  • 16. HermeneuticsFriedrich Schleiermacher (1768 – 1834) explored the nature ofunderstanding in relation not just to the problem ofdeciphering sacred texts, but to all human texts and modes ofcommunication.Wilhelm Dilthey broadened hermeneutics even more byrelating interpretation to all historical objectifications.Understanding moves from the outer manifestations of humanaction and productivity to explore their inner meaningMartin Heideggers philosophical hermeneutics shifted thefocus from interpretation to existential understanding, whichwas treated more as a direct, non-mediated, thus in a sensemore authentic way of being in the world than simply as away of knowing.
  • 17. HermeneuticsHans-Georg Gadamers hermeneutics is a development of thehermeneutics of his teacher, Heidegger.Paul Ricoeur developed a hermeneutics based on Heideggersconcepts, although his own work differs in many ways fromthat of GadamersJürgen Habermas criticized the conservatism of previoushermeneutics, especially Gadamer, because the focus ontradition seemed to undermine possibilities for social criticismand transformation
  • 18. Critical theoryCritical theory was defined by Max Horkheimer of theFrankfurt School of social science in his 1937 essay“Traditional and Critical Theory”:Critical theory is a social theory oriented toward critiquing andchanging society as a whole, in contrast to traditional theoryoriented only to understanding or explaining it.Jürgen Habermas in 1968 in his Erkenntnis und Interesse(Knowledge and Human Interests), critical social theory isa form of self-reflective knowledge involving both understandingand theoretical explanation to reduce entrapment in systems ofdomination or dependence, obeying the emancipatory interest inexpanding the scope of autonomy and reducing the scope ofdomination.
  • 19. Critical theory Core concepts are:(1) That critical social theory should be directed at the totality of society in its historical specificity (i.e. how it came to be configured at a specific point in time), and(2) That critical theory should improve understanding of society by integrating all the major social sciences, including economics, sociology, history, political science, anthropology, and psychology. Although this conception of critical theory originated with the Frankfurt School, it also prevails among other recent social scientists, such as Pierre Bourdieu, Louis Althusser, Michel Foucault, Norman Fairclaugh as well as critical feminist social scientists.
  • 20. Induction(or inductive reasoning, sometimes called inductive logic),Induction or inductive reasoning, sometimes calledinductive logic, is the process of reasoning in which thepremises of an argument are believed to support theconclusion but do not entail it; i.e. they do not ensure itstruth.Induction is a form of reasoning that makes generalizationsbased on individual instances
  • 21. Types of inductive reasoning Generalisation A generalisation (more accurately, an inductive generalisation) proceeds from a premise about a sample to a conclusion about the population. The proportion (p) of the sample has attribute A. Therefore: The proportion (P) of the population has attribute A. How great the support which the premises provide for the conclusion is dependent on(a) the number of individuals in the sample group compared to the number in the population; and(b) the randomness of the sample. The hasty generalisation and biased sample are fallacies related to generalisation.
  • 22. Types of inductive reasoningStatistical syllogismA statistical syllogism proceeds from a generalization to aconclusion about an individual.A proportion (p) of population P has attribute A.An individual I is a member of P.Therefore:There is a probability which corresponds to (p) that I has A.
  • 23. Types of inductive reasoningSimple inductionSimple induction proceeds from a premise about a samplegroup to a conclusion about another individual.Proportion (p) of the known instances of population P hasattribute A.Individual I is another member of P.Therefore:There is a probability corresponding to (p) that I has A.This is a combination of a generalization and a statisticalsyllogism, where the conclusion of the generalization is alsothe first premise of the statistical syllogism.
  • 24. Types of inductive reasoningAnalogyAn (inductive) analogy proceeds from known similaritiesbetween two things to a conclusion about an additionalattribute common to both things.P is similar to Q.P has attribute A.Therefore:Q has attribute A.An analogy relies on the inference that the properties known to beshared (the similarities) imply that A is also a shared property. Thesupport which the premises provide for the conclusion is dependentupon the relevance and number of the similarities between P and Q.The fallacy related to this process is false analogy.
  • 25. Types of inductive reasoningPredictionA prediction draws a conclusion about a future individualfrom a past sample.Proportion (p) of observed members of group G have hadattribute A.Therefore:There is a probability corresponding to (p) that othermembers of group G will have attribute A when observedin the (near) future.
  • 26. Types of inductive reasoningCausal inferenceA causal inference draws a conclusion about a causalconnection based on the conditions of the occurrence of aneffect.The two factors (or variables) X and Y co-variatessystematicallyTherefore:X is the cause of YPremises about the correlation of two things can indicate acausal relationship between them, but additional factorsmust be confirmed to establish the exact form of the causalrelationship.
  • 27. Induction - criticismHistorically, Sextus Empiricus (c. 160-210 AD), questionedhow the truth of the Universals can be established byexamining some of the Particulars. Examining all theparticulars is difficult as they are infinite in number.David Hume (1711 – 1776) denied the logical admissibilityof inductive reasoning, in particular concerning causality.During the twentieth century, Karl Popper (1902-1994)have disputed the existence, necessity and validity of anyinductive reasoning, including probabilistic reasoning.Scientists still rely on induction nevertheless.That, however, is exactly what Popper and dispute.Scientists cannot rely on induction simply because it doesnot exist, he is arguing.
  • 28. Deductive reasoningis the kind of reasoning where the conclusion isnecessitated by previously known premises.If the premises are true then the conclusion must be true.For instance, beginning with the premises "sharks are fish"and "all fish have fins", you may conclude that "sharkshave fins".This is distinguished from inductive reasoning andabductive reasoning where inferences can be made withsome likelihood but never with complete certainty.Deductive reasoning is dependent on its premises.That is, a false premise can possibly lead to a false result,and inconclusive premises will also yield an inconclusiveconclusion.
  • 29. Deductive reasoningAll men are mortal (major premise),Socrates is a man (minor premise),Therefore Socrates is mortal. Note that replacing "mortal" with any nonsensical property will not affect the (logical) validity of the argument:All men are idiots,Socrates is a man,Therefore Socrates is an idiot
  • 30. Deductive reasoningFalsifiability (or refutability or testability)is the logical possibility that an assertion can be shownfalse by an observation or a physical experiment."Falsifiable" does not mean false; rather, it means thatsomething is capable of disproof.When an assertion has been shown to be false, then somecontrary examples or exceptions to the assertion have beendemonstrated, observed or shown. Falsifiability is animportant concept in science and the philosophy of science.Some philosophers and scientists, most notably KarlPopper, have asserted that a hypothesis, proposition ortheory is scientific only if it is falsifiable.
  • 31. Falsifiability - the criterion of demarcation?Popper uses falsification as a criterion of demarcation to drawa sharp line between those theories that are scientific and thosethat are unscientific. Popper claimed that, if a theory isfalsifiable, then it is scientific; if it is not falsifiable, then it isnot open to scientific investigation.We may agree with this or not but it is always useful toknow if a statement or theory is (potentially) falsifiable,if for no other reason than that it provides us with anunderstanding of the ways in which one might assess thetheory. One might at the least be saved from attempting tofalsify a non-falsifiable theory, or come to see anunfalsifiable theory as unsupportable.
  • 32. Abductionor inference to the best explanation, is a method of reasoningin which one chooses the hypothesis that would, if true,best explain the relevant evidence.Abductive reasoning starts from a set of accepted (oftencounter-intuitive) facts and infers to their most likely, orbest, explanations.
  • 33. AbductionThe philosopher Charles Peirce introduced abduction intomodern logic. In his works before 1900, he mostly uses theterm to mean the use of a known rule to explain anobservation, e.g., “if it rains the grass is wet” is a knownrule used to explain that the grass is wet. In other words, itwould be more technically correct to say, "If the grass iswet, the most probable explanation is that it recentlyrained."He later used the term to mean creating new hypothesis toexplain new observations, emphasizing that abduction is theonly logical process that actually creates anything new.http://www.youtube.com/watch?v=ltP2t9nq9fI
  • 34. Methods for comparative causal analysisMethod of agreement (Comparing most different cases)"If two or more instances of the phenomenon under investigation have only one circumstance in common, the circumstance in which alone all the instances agree, is the cause (or effect) of the given phenomenon."For a property to be a necessary condition it must always be present if the effect is present. Since this is so, then we are interested in looking at cases where the effect is present and taking note of which properties, among those considered to be possible necessary conditions are present and which are absent. Obviously, any properties which are absent when the effect is present cannot be necessary conditions for the effect.Symbolically, the method of agreement can be represented as: A B C D occur together with w x y z A E F G occur together with w t u v —————————————————— Therefore A is the cause, the effect, or part of the cause of w.
  • 35. Methods for comparative causal analysisMethod of difference (Comparing most similar cases)“If an instance in which the phenomenon under investigation occurs, and an instance in which it does not occur, have every circumstance in common save one, that one occurring only in the former; the circumstance in which alone the two instances differ, is the effect, or the cause, or an indispensable part of the cause, of the phenomenon.”A B C D occur together with w x y zB C D occur together with w y z——————————————————Therefore A is the cause, or the effect, or a part of the cause of x.