110902 theory of science

Critical thinkingCritical thinking

Sapere Aude:Sapere Aude:

Having determinationHaving determination

and courageand courage

to think independentlyto think independently

Scientific tools for Scientific tools for independent critical thinkingindependent critical thinking

Practical toolsPractical tools

- Methodology and - Methodology and methodsmethods

Theoretical toolsTheoretical tools

- Philosophy and theory of - Philosophy and theory of sciencescience

PositivismPositivism

The idea (analysis based on observation) appears in Ibn al-The idea (analysis based on observation) appears in Ibn al-Haytham's 11th Century text “Book of Optics”Haytham's 11th Century text “Book of Optics”

Positivism - an approach to the philosophy of science, deriving Positivism - an approach to the philosophy of science, deriving from Enlightenment thinkers (Voltaire, Rossaueu, Kant)from Enlightenment thinkers (Voltaire, Rossaueu, Kant)

Logical positivism - a school of philosophy developed in the Logical positivism - a school of philosophy developed in the 1920s by the Vienna Circle (Moritz Schlick)1920s by the Vienna Circle (Moritz Schlick)

Social positivism - in social sciences, an approach to Social positivism - in social sciences, an approach to understanding the world based on science (Auguste Comte)understanding the world based on science (Auguste Comte)

Postpositivism - a philosophical stance following positivismPostpositivism - a philosophical stance following positivism

PositivismPositivism

Positivism is a philosophy that states that the only Positivism is a philosophy that states that the only authentic knowledge is scientific knowledge, and that authentic knowledge is scientific knowledge, and that

such knowledge can only come from positive such knowledge can only come from positive affirmation of theories through strict scientific method. affirmation of theories through strict scientific method. It was developed by Auguste Comte (1798 – 1857). It was developed by Auguste Comte (1798 – 1857).

He was a French thinker who coined the term He was a French thinker who coined the term "sociology." He is remembered for being the first to "sociology." He is remembered for being the first to

apply the scientific method to the social world.apply the scientific method to the social world.

““The law of three stages” The law of three stages”

An idea developed by Auguste Comte. It states that An idea developed by Auguste Comte. It states that knowledge of any subject always begins in theologic knowledge of any subject always begins in theologic

form, passes to the metaphysical form, and finally form, passes to the metaphysical form, and finally becomes positive.becomes positive.

The Theologic form refers to The Theologic form refers to explanation by spirits, explanation by spirits, gods, etc.gods, etc.

The Metaphysical form refers to The Metaphysical form refers to explanation by explanation by abstract philosophical explanation.abstract philosophical explanation.

Positivity refers to scientific Positivity refers to scientific explanation based on explanation based on observation, experiment, and comparison.observation, experiment, and comparison.

Falsificationism Falsificationism

Karl Popper, a well-known critic of logical positivism, Karl Popper, a well-known critic of logical positivism, published the book Logik der Forschung in 1934published the book Logik der Forschung in 1934

In it he presented an influential alternative to the In it he presented an influential alternative to the verifiability criterion of meaning, verifiability criterion of meaning, defining scientific defining scientific statements in terms of falsifiability.statements in terms of falsifiability.

Some key features of modern positivism Some key features of modern positivism (sometimes referred to as “the received view of science”):(sometimes referred to as “the received view of science”):

A focus on science as a product, a linguistic or numerical set A focus on science as a product, a linguistic or numerical set of statements of statements

A concern with demonstrating the logical structure and A concern with demonstrating the logical structure and coherence of these statementscoherence of these statements

An insistence on that statements should be testable, that is An insistence on that statements should be testable, that is amenable to being verified, confirmed, or falsified by the amenable to being verified, confirmed, or falsified by the empirical observation of reality; empirical observation of reality;

The belief that science is markedly cumulative The belief that science is markedly cumulative

The belief that science is transcultural; The belief that science is transcultural;

The belief that science rests on specific results that are The belief that science rests on specific results that are dissociated from the personality and social position of the dissociated from the personality and social position of the investigator; investigator;

The belief that science contains theories or research traditions The belief that science contains theories or research traditions that are largely commensurable; that are largely commensurable;

The belief that science involves the idea of the unity of The belief that science involves the idea of the unity of science, that there is, underlying the various scientific science, that there is, underlying the various scientific disciplines, basically one logic of scientific inquiry about one disciplines, basically one logic of scientific inquiry about one real world.real world.

- the goal of inquiry is to explain and predict. - the goal of inquiry is to explain and predict. scientific knowledge is testable. research can scientific knowledge is testable. research can be proved only by empirical means, not be proved only by empirical means, not argumentationsargumentations

-science does not equal common sense. science does not equal common sense. Researchers must be careful not to let Researchers must be careful not to let common sense bias their research.common sense bias their research.

- relation of theory to practice - science should - relation of theory to practice - science should be as value-free as possible, and the ultimate be as value-free as possible, and the ultimate goal of science is to produce knowledge, goal of science is to produce knowledge, regardless of politics, morals, values, etc. regardless of politics, morals, values, etc. involved in the research.involved in the research.

Positivism

Critique of Positivism

Internal critique

Context stripping

Exclusion of meaning and purpose

Etic (outsider) / Emic (insider) dilemma

General data vs. individual cases

Exclusion of discovery dimension (hyp-ded)

Critique of Positivism

External critique

Facts impregnated by theory/ paradigm/ discourse

Underdetermination of theory

(Facts are always open for different interpretations)

Facts are impregnated by values

Facts dependent on inquirer-inquired interaction

HermeneuticsHermeneutics

Essentially, hermeneutics involves cultivating Essentially, hermeneutics involves cultivating the ability to understand things from the ability to understand things from somebody else's point of view, and to somebody else's point of view, and to appreciate the cultural and social forces that appreciate the cultural and social forces that may have influenced their outlook.may have influenced their outlook.

The word hermeneutics is a term derived from The word hermeneutics is a term derived from 'Ερμηνεύς, (hermeneuo, 'translate' or 'Ερμηνεύς, (hermeneuo, 'translate' or 'interpret‘), related to the name of the Greek 'interpret‘), related to the name of the Greek god Hermes in his role as the interpreter of the god Hermes in his role as the interpreter of the messages of the gods.messages of the gods.


Hermeneutics in the Western world, as a general Hermeneutics in the Western world, as a general science of text interpretation, can be traced back to science of text interpretation, can be traced back to two sources. two sources. One source was the ancient Greek rhetoricians' study One source was the ancient Greek rhetoricians' study of literature, which came to fruition in Alexandria. of literature, which came to fruition in Alexandria. The other source has been the traditions of Biblical The other source has been the traditions of Biblical exegesisexegesis

The discipline of hermeneutics emerged with the new The discipline of hermeneutics emerged with the new humanist education of the 15th century as a historical humanist education of the 15th century as a historical and critical methodology for analyzing texts. and critical methodology for analyzing texts. Thus hermeneutics Thus hermeneutics expandedexpanded from its medieval role from its medieval role explaining the correct analysis of the Bible.explaining the correct analysis of the Bible.


Friedrich SchleiermacherFriedrich Schleiermacher (1768 – 1834) explored (1768 – 1834) explored the nature of understanding in relation not just to the the nature of understanding in relation not just to the problem of deciphering sacred texts, but to all human problem of deciphering sacred texts, but to all human texts and modes of communication. texts and modes of communication.

Wilhelm DiltheyWilhelm Dilthey broadened hermeneutics even more broadened hermeneutics even more by relating interpretation to all historical by relating interpretation to all historical objectifications. Understanding moves from the outer objectifications. Understanding moves from the outer manifestations of human action and productivity to manifestations of human action and productivity to explore their inner meaningexplore their inner meaning

Martin Heidegger's philosophical hermeneutics shifted the focus from interpretation to existential understanding, which was treated more as a direct, non-mediated, thus in a sense more authentic way of being in the world than simply as a way of knowing.


Hans-Georg Gadamer'sHans-Georg Gadamer's hermeneutics is a hermeneutics is a development of the hermeneutics of his teacher, development of the hermeneutics of his teacher, Heidegger.Heidegger.

Paul RicoeurPaul Ricoeur developed a hermeneutics based on developed a hermeneutics based on Heidegger's concepts, although his own work differs in Heidegger's concepts, although his own work differs in many ways from that of Gadamer'smany ways from that of Gadamer's

Jürgen HabermasJürgen Habermas criticized the conservatism of criticized the conservatism of previous hermeneutics, especially Gadamer, because previous hermeneutics, especially Gadamer, because the focus on tradition seemed to undermine the focus on tradition seemed to undermine possibilities for social criticism and transformationpossibilities for social criticism and transformation

Critical theoryCritical theory

Critical theory was defined by Critical theory was defined by Max HorkheimerMax Horkheimer of of the Frankfurt School of social science in his 1937 the Frankfurt School of social science in his 1937 essay “Traditional and Critical Theory”: essay “Traditional and Critical Theory”: Critical theory is a social theory oriented toward Critical theory is a social theory oriented toward critiquing and changing society as a whole, in critiquing and changing society as a whole, in contrast to traditional theory oriented only to contrast to traditional theory oriented only to understanding or explaining it.understanding or explaining it.

Jürgen Habermas in 1968 in his Erkenntnis und Jürgen Habermas in 1968 in his Erkenntnis und Interesse (Knowledge and Human Interests), critical Interesse (Knowledge and Human Interests), critical social theory is social theory is a form of self-reflective knowledge a form of self-reflective knowledge involving both understanding and theoretical involving both understanding and theoretical explanation to reduce entrapment in systems of explanation to reduce entrapment in systems of domination or dependence, obeying the domination or dependence, obeying the emancipatory interest in expanding the scope of emancipatory interest in expanding the scope of autonomy and reducing the scope of domination.autonomy and reducing the scope of domination.

Critical theoryCritical theory

Core concepts are: Core concepts are: (1)(1)That critical social theory should be That critical social theory should be directed at the directed at the

totality of society in its historical specificitytotality of society in its historical specificity (i.e. how (i.e. how it came to be configured at a specific point in time), it came to be configured at a specific point in time), and and

(2)(2)That critical theory should That critical theory should improve understanding improve understanding of society by integrating all the major social of society by integrating all the major social sciences, including economics, sociology, history, sciences, including economics, sociology, history, political science, anthropology, and psychology. political science, anthropology, and psychology.

Although this conception of critical theory Although this conception of critical theory originated with the Frankfurt School, it also prevails originated with the Frankfurt School, it also prevails among other recent social scientists, such as Pierre among other recent social scientists, such as Pierre Bourdieu, Louis Althusser, Michel Foucault, Norman Bourdieu, Louis Althusser, Michel Foucault, Norman Fairclaugh as well as critical feminist social Fairclaugh as well as critical feminist social scientists.scientists.

InductionInduction(or inductive reasoning, sometimes called inductive logic), (or inductive reasoning, sometimes called inductive logic),

Induction or inductive reasoning, sometimes called Induction or inductive reasoning, sometimes called inductive logic, is the process of reasoning in which inductive logic, is the process of reasoning in which the premises of an argument are believed to the premises of an argument are believed to support the conclusion but do not entail it; i.e. they support the conclusion but do not entail it; i.e. they do not ensure its truth. do not ensure its truth.

Induction is a form of reasoning that makes Induction is a form of reasoning that makes generalizations based on individual instancesgeneralizations based on individual instances

Types of inductive reasoningTypes of inductive reasoning

GeneralisationGeneralisationA generalisation (more accurately, an inductive A generalisation (more accurately, an inductive generalisation) proceeds from a premise about a sample to a generalisation) proceeds from a premise about a sample to a conclusion about the population.conclusion about the population.

The proportion (p) of the sample has attribute A. The proportion (p) of the sample has attribute A. Therefore: Therefore: The proportion (P) of the population has attribute A. The proportion (P) of the population has attribute A.

How great the support which the premises provide for the How great the support which the premises provide for the conclusion is dependent on conclusion is dependent on

(a)(a) the number of individuals in the sample group compared to the number of individuals in the sample group compared to the number in the population; and the number in the population; and

(b)(b) the randomness of the sample.the randomness of the sample. The The hasty generalisationhasty generalisation and and biased samplebiased sample are fallacies are fallacies related to generalisation.related to generalisation.


Statistical syllogismStatistical syllogismA statistical syllogism proceeds from a A statistical syllogism proceeds from a generalization to a conclusion about an individual.generalization to a conclusion about an individual.

A proportion (p) of population P has attribute A. A proportion (p) of population P has attribute A. An individual I is a member of P. An individual I is a member of P. Therefore: Therefore: There is a probability which corresponds to (p) that I There is a probability which corresponds to (p) that I has A. has A.


Simple inductionSimple inductionSimple induction proceeds from a premise about a Simple induction proceeds from a premise about a sample group to a conclusion about another sample group to a conclusion about another individual.individual.

Proportion (p) of the known instances of population Proportion (p) of the known instances of population P has attribute A. P has attribute A. Individual I is another member of P. Individual I is another member of P. Therefore: Therefore: There is a probability corresponding to (p) that I has There is a probability corresponding to (p) that I has A.A.

This is a combination of a This is a combination of a generalizationgeneralization and a and a statistical syllogism,statistical syllogism, where the conclusion of the where the conclusion of the generalization is also the first premise of the generalization is also the first premise of the statistical syllogism.statistical syllogism.


AnalogyAnalogyAn (inductive) analogy proceeds from known An (inductive) analogy proceeds from known similarities between two things to a conclusion similarities between two things to a conclusion about an additional attribute common to both about an additional attribute common to both things.things.

P is similar to Q. P is similar to Q. P has attribute A. P has attribute A. Therefore: Therefore: Q has attribute A.Q has attribute A.

An analogy relies on the inference that the properties known An analogy relies on the inference that the properties known to be shared (the similarities) imply that A is also a shared to be shared (the similarities) imply that A is also a shared property. The support which the premises provide for the property. The support which the premises provide for the conclusion is dependent upon the relevance and number of conclusion is dependent upon the relevance and number of the similarities between P and Q. The fallacy related to this the similarities between P and Q. The fallacy related to this process is false analogy.process is false analogy.


PredictionPredictionA prediction draws a conclusion about a future A prediction draws a conclusion about a future individual from a past sample.individual from a past sample.

Proportion (p) of observed members of group G Proportion (p) of observed members of group G have had attribute A. have had attribute A.

Therefore: Therefore: There is a probability corresponding to (p) that There is a probability corresponding to (p) that other members of group G will have attribute A other members of group G will have attribute A

when observed in the (near) future.when observed in the (near) future.


Causal inferenceCausal inferenceA causal inference draws a conclusion about a A causal inference draws a conclusion about a causal connection based on the conditions of the causal connection based on the conditions of the occurrence of an effect. occurrence of an effect.

The two factors (or variables) X and Y co-variates The two factors (or variables) X and Y co-variates systematicallysystematicallyTherefore:Therefore:X is the cause of YX is the cause of Y

Premises about the correlation of two things can Premises about the correlation of two things can indicate a causal relationship between them, but indicate a causal relationship between them, but additional factors must be confirmed to establish additional factors must be confirmed to establish the exact form of the causal relationship.the exact form of the causal relationship.

Induction - criticismInduction - criticism

Historically, Historically, Sextus EmpiricusSextus Empiricus (c. 160-210 AD), (c. 160-210 AD), questioned how the truth of the Universals can be questioned how the truth of the Universals can be established by examining some of the Particulars. established by examining some of the Particulars. Examining all the particulars is difficult as they are Examining all the particulars is difficult as they are infinite in number. infinite in number. David HumeDavid Hume (1711 – 1776) denied the logical (1711 – 1776) denied the logical admissibility of inductive reasoning, in particular admissibility of inductive reasoning, in particular concerning causality. During the twentieth century, concerning causality. During the twentieth century, Karl PopperKarl Popper (1902-1994) have disputed the (1902-1994) have disputed the existence, necessity and validity of any inductive existence, necessity and validity of any inductive reasoning, including probabilistic reasoning. reasoning, including probabilistic reasoning. Scientists still rely on induction nevertheless. Scientists still rely on induction nevertheless. That, however, is exactly what Popper and dispute. That, however, is exactly what Popper and dispute. Scientists cannot rely on induction simply because Scientists cannot rely on induction simply because it does not exist, he is arguing.it does not exist, he is arguing.

Deductive reasoningDeductive reasoning

is the kind of reasoning where the conclusion is is the kind of reasoning where the conclusion is necessitated by previously known premises. necessitated by previously known premises. If the premises are true then the conclusion If the premises are true then the conclusion must must be truebe true. For instance, beginning with the premises . For instance, beginning with the premises "sharks are fish" and "all fish have fins", you may "sharks are fish" and "all fish have fins", you may conclude that "sharks have fins". conclude that "sharks have fins". This is distinguished from This is distinguished from inductive reasoninginductive reasoning and and abductive reasoningabductive reasoning where inferences can where inferences can be made with some likelihood but never with be made with some likelihood but never with complete certainty.complete certainty.

Deductive reasoning Deductive reasoning is dependent on its is dependent on its premisespremises. . That is, a false premise can possibly lead to a false That is, a false premise can possibly lead to a false result, and inconclusive premises will also yield an result, and inconclusive premises will also yield an inconclusive conclusion.inconclusive conclusion.


All men are mortal (major premise), All men are mortal (major premise), Socrates is a man (minor premise), Socrates is a man (minor premise), Therefore Socrates is mortal. Therefore Socrates is mortal.

Note that replacing "mortal" with any nonsensical Note that replacing "mortal" with any nonsensical property will not affect the (logical) validity of the property will not affect the (logical) validity of the argument:argument:

All men are idiots, All men are idiots, Socrates is a man, Socrates is a man, Therefore Socrates is an idiotTherefore Socrates is an idiot


Falsifiability (or refutability or testability) Falsifiability (or refutability or testability)

is the logical possibility that an assertion can be is the logical possibility that an assertion can be shown false by an observation or a physical shown false by an observation or a physical experiment. "Falsifiable" does not mean false; experiment. "Falsifiable" does not mean false; rather, it means that something is capable of rather, it means that something is capable of disproof.disproof.

When an assertion has been shown to be false, then When an assertion has been shown to be false, then some contrary examples or exceptions to the some contrary examples or exceptions to the assertion have been demonstrated, observed or assertion have been demonstrated, observed or shown. Falsifiability is an important concept in shown. Falsifiability is an important concept in science and the philosophy of science.science and the philosophy of science.

Some philosophers and scientists, most notably Karl Some philosophers and scientists, most notably Karl Popper, have asserted that a hypothesis, Popper, have asserted that a hypothesis, proposition or theory is scientific only if it is proposition or theory is scientific only if it is falsifiable.falsifiable.

Falsifiability - the criterion of demarcation?Falsifiability - the criterion of demarcation?

Popper uses falsification as a Popper uses falsification as a criterion of criterion of demarcation to draw a sharp line between those demarcation to draw a sharp line between those theories that are scientific and those that are theories that are scientific and those that are unscientific.unscientific. Popper claimed that, if a theory is Popper claimed that, if a theory is falsifiable, then it is scientific; if it is not falsifiable, falsifiable, then it is scientific; if it is not falsifiable, then it is not open to scientific investigation.then it is not open to scientific investigation.

We may agree with this or not but it is always We may agree with this or not but it is always useful to know if a statement or theory is useful to know if a statement or theory is (potentially) falsifiable, (potentially) falsifiable, if for no other reason than that it provides us with if for no other reason than that it provides us with an understanding of the ways in which one might an understanding of the ways in which one might assess the theory. One might at the least be saved assess the theory. One might at the least be saved from attempting to falsify a non-falsifiable theory, from attempting to falsify a non-falsifiable theory, or come to see an unfalsifiable theory as or come to see an unfalsifiable theory as unsupportable.unsupportable.

Abduction Abduction

or or inference to the best explanation,inference to the best explanation, is a method of is a method of reasoning in which one chooses the hypothesis that reasoning in which one chooses the hypothesis that would, if true, best explain the relevant evidence.would, if true, best explain the relevant evidence.

Abductive reasoning starts from a set of accepted Abductive reasoning starts from a set of accepted (often counter-intuitive) facts and infers to their (often counter-intuitive) facts and infers to their most likely, or best, explanations. most likely, or best, explanations.

Abduction Abduction

The philosopher Charles Peirce introduced The philosopher Charles Peirce introduced abduction into modern logic. In his works before abduction into modern logic. In his works before 1900, he mostly uses the term to mean the use of a 1900, he mostly uses the term to mean the use of a known rule to explain an observation, e.g., “if it known rule to explain an observation, e.g., “if it rains the grass is wet” is a known rule used to rains the grass is wet” is a known rule used to explain that the grass is wet. In other words, it explain that the grass is wet. In other words, it would be more technically correct to say, "If the would be more technically correct to say, "If the grass is wet, the most probable explanation is that grass is wet, the most probable explanation is that it recently rained."it recently rained."

He later used the term to mean creating new He later used the term to mean creating new hypothesis to explain new observations, hypothesis to explain new observations, emphasizing that emphasizing that abduction is the only logical abduction is the only logical process that actually creates anything newprocess that actually creates anything new..http://www.youtube.com/watch?v=ltP2t9nq9fI

http://www.youtube.com/watch?v=ltP2t9nq9fI

Methods for comparative causal analysisMethods for comparative causal analysis

Method of agreement (Comparing most different Method of agreement (Comparing most different cases)cases)

"If two or more instances of the phenomenon under investigation "If two or more instances of the phenomenon under investigation have only one circumstance in common, the circumstance in have only one circumstance in common, the circumstance in which alone all the instances agree, is the cause (or effect) of which alone all the instances agree, is the cause (or effect) of the given phenomenon."the given phenomenon."

For a property to be a For a property to be a necessary condition it must always be condition it must always be present if the effect is present. Since this is so, then we are present if the effect is present. Since this is so, then we are interested in looking at cases where the effect is present and interested in looking at cases where the effect is present and taking note of which properties, among those considered to be taking note of which properties, among those considered to be 'possible necessary conditions' are present and which are 'possible necessary conditions' are present and which are absent. Obviously, any properties which are absent when the absent. Obviously, any properties which are absent when the effect is present cannot be necessary conditions for the effect.effect is present cannot be necessary conditions for the effect.

Symbolically, the method of agreement can be represented as:Symbolically, the method of agreement can be represented as:A B C D occur together with w x y z A B C D occur together with w x y z A E F G occur together with w t u v 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.Therefore A is the cause, the effect, or part of the cause of w.

http://en.wikipedia.org/wiki/Necessary_and_sufficient_conditions

Methods for comparative causal analysisMethods for comparative causal analysis

Method of difference (Comparing most similar Method of difference (Comparing most similar cases)cases)

““If an instance in which the phenomenon under If an instance in which the phenomenon under investigation occurs, and an instance in which it does investigation occurs, and an instance in which it does not occur, have every circumstance in common save not occur, have every circumstance in common save one, that one occurring only in the former; the one, that one occurring only in the former; the circumstance in which alone the two instances differ, is circumstance in which alone the two instances differ, is the effect, or the cause, or an indispensable part of the the effect, or the cause, or an indispensable part of the cause, of the phenomenon.”cause, of the phenomenon.”

A B C D occur together with w x y zA B C D occur together with w x y zB C D occur together with w y zB C D occur together with w y z————————————————————————————————————Therefore A is the cause, or the effect, or a part of the Therefore A is the cause, or the effect, or a part of the

cause of x.cause of x.

110902 theory of science

Documents

Transcript of 110902 theory of science