Science and Science and Scientific DiscoveryScientific Discovery

Time Series TestTime Series TestWilliam at 6 months, before first Christmas

William at 18 months, after first Christmas

Conclusion: Getting Christmas presents makes children hate Santa. Possible maturation threats, and hatred of dad for letting mom dress him that day. Note that no instrumentation threat indicates Santa is real.

What Counts as Scientific What Counts as Scientific Knowledge?Knowledge?

We “know” many things:We “know” many things: The sun rises in the morningThe sun rises in the morning Its best to treat others as you want to be treatedIts best to treat others as you want to be treated Water boils at 100cWater boils at 100c The working class is exploitedThe working class is exploited Wars are caused by bargaining failuresWars are caused by bargaining failures

Which of these statements count as Which of these statements count as scientific?scientific?

Philosophy of Science is a theory of Philosophy of Science is a theory of knowledge (ontology) and a theory about knowledge (ontology) and a theory about the progress of knowledge (epistemology).the progress of knowledge (epistemology).

Science and Its RivalsScience and Its Rivals

Primary divide between non-science Primary divide between non-science and science:and science: Science explains outcomes in terms of Science explains outcomes in terms of

natural laws, non-science permits natural laws, non-science permits supernatural causes.supernatural causes.

Secondary divide between science Secondary divide between science and pseudo-science.and pseudo-science. Science is falsifiable, pseudo-science is Science is falsifiable, pseudo-science is

not.not.

PopperPopper Science and Pseudo-scienceScience and Pseudo-science

Many systems of thought share a similar Many systems of thought share a similar structure: premises are taken as given and structure: premises are taken as given and implications are derived logically. implications are derived logically.

This is true for theories, as well as ideologies.This is true for theories, as well as ideologies. All can be useful guides for human behavior.All can be useful guides for human behavior.

The key difference between science and The key difference between science and pseudo-science (and non-science) is the pseudo-science (and non-science) is the criterion of criterion of falsifiabilityfalsifiability.. Theories are open to potential refutation. Theories are open to potential refutation.

Ideologies (and religions) are not.Ideologies (and religions) are not.

Hypothetico-Deductive ReasoningHypothetico-Deductive Reasoning

Falsifiability implies that deduction is the only Falsifiability implies that deduction is the only valid form of scientific reasoning.valid form of scientific reasoning. Induction cannot be falsified. Correlation between X Induction cannot be falsified. Correlation between X

and Y stands as “fact.” and Y stands as “fact.” Thus, much of what scientists do – that is, observe – Thus, much of what scientists do – that is, observe –

was classified as non-science.was classified as non-science. Also implies that the task of science is to Also implies that the task of science is to

disconfirm theories. disconfirm theories. Theories can only be supported. Valid theories are Theories can only be supported. Valid theories are

those not yet proven false. those not yet proven false. Scientists immediately reject theories once Scientists immediately reject theories once

disconfirming evidence is found (naïve falsification).disconfirming evidence is found (naïve falsification).

CritiqueCritique Principle of falsification still important.Principle of falsification still important. Tests still aim, in part, to disconfirm theories.Tests still aim, in part, to disconfirm theories. But Popper’s criterion and its implications did not But Popper’s criterion and its implications did not

embody what people who identify themselves as embody what people who identify themselves as scientists actually do.scientists actually do. Scientists typically pursue confirming experiments.Scientists typically pursue confirming experiments. Scientists do not reject theories because they Scientists do not reject theories because they

encounter some disconfirming evidence.encounter some disconfirming evidence. Steven Weinberg (Nobel in Physics): there “is no Steven Weinberg (Nobel in Physics): there “is no

theory that is not contradicted by some experiment.”theory that is not contradicted by some experiment.”

KuhnKuhn

Structure of Scientific Revolutions Structure of Scientific Revolutions (1962).(1962). ParadigmParadigm is a set of generally (if not is a set of generally (if not

universally) shared assumptions that universally) shared assumptions that underlay one or more theories. underlay one or more theories. Represented in “textbook” version of the field.Represented in “textbook” version of the field. Paradigm initiates new entrants to the field Paradigm initiates new entrants to the field

into the dominant set of ideas.into the dominant set of ideas.

Normal ScienceNormal Science Normal Science: occurs within a paradigm.Normal Science: occurs within a paradigm. Does not search for disconfirming evidence or Does not search for disconfirming evidence or

anomalies.anomalies. Ambition is to extend the paradigm to already Ambition is to extend the paradigm to already

known and new phenomena, to explain more known and new phenomena, to explain more phenomena in terms of the theory.phenomena in terms of the theory.

Normal science is Normal science is puzzle solvingpuzzle solving according to according to the rules (assumptions) laid down by the the rules (assumptions) laid down by the paradigm.paradigm.

Phenomena that do not fit the paradigm are Phenomena that do not fit the paradigm are often not even “seen.” often not even “seen.”

Revolutionary ScienceRevolutionary Science

In extending the paradigm, scientists encounter In extending the paradigm, scientists encounter unresolved puzzles or unresolved puzzles or anomaliesanomalies..

Accumulation of anomalies eventually brings the Accumulation of anomalies eventually brings the paradigm into question, but does not lead to the paradigm into question, but does not lead to the falsification or rejection of the paradigm.falsification or rejection of the paradigm.

Revolution occurs only when a new and better Revolution occurs only when a new and better theory able to resolve the anomalies arises.theory able to resolve the anomalies arises.

Science does not proceed by naïve falsification Science does not proceed by naïve falsification but by the development of better theory.but by the development of better theory.

Role of AssumptionsRole of Assumptions Assumptions are never “true.” They embody the Assumptions are never “true.” They embody the

analogy that informs the theory. Theories are analogy that informs the theory. Theories are intended to capture the “essence” of a particular intended to capture the “essence” of a particular setting/event/process. setting/event/process.

In normal science, assumptions are treated as In normal science, assumptions are treated as unproblematic. They “make sense” given the unproblematic. They “make sense” given the utility of the prevailing paradigm.utility of the prevailing paradigm.

In revolutions, assumptions are called into In revolutions, assumptions are called into question and some or all are overthrown. question and some or all are overthrown. Previous assumptions are now regarded as Previous assumptions are now regarded as naïve.naïve.

Paradigm ChangeParadigm Change Science is an inherently social phenomena. Science is an inherently social phenomena.

“Knowledge” depends on the assent of the “Knowledge” depends on the assent of the community of scholars.community of scholars.

Choice of a new paradigm is dependent on the Choice of a new paradigm is dependent on the subjective judgment of the relevant community subjective judgment of the relevant community of scientists.of scientists. Tests, anomalies, and explanations only make sense Tests, anomalies, and explanations only make sense

in terms of a particular paradigm. Because they in terms of a particular paradigm. Because they possess incommensurable assumptions, difficult to possess incommensurable assumptions, difficult to have “head-to-head” competitions between theories have “head-to-head” competitions between theories from different paradigms.from different paradigms.

There are few decisive tests, since the very meaning There are few decisive tests, since the very meaning of the test typically differs across paradigms.of the test typically differs across paradigms.

Adoption of a paradigm is an “all-or-nothing” affair.Adoption of a paradigm is an “all-or-nothing” affair.

Paradigm Change continuedParadigm Change continued Most important, the full problem-solving abilities Most important, the full problem-solving abilities

of new paradigm are not yet demonstrated at the of new paradigm are not yet demonstrated at the time the paradigm is adopted. time the paradigm is adopted.

Choice of paradigm, then, is a collective Choice of paradigm, then, is a collective exercise based on beliefs and, in part, on exercise based on beliefs and, in part, on subjective judgments of relevant scholars. Led to subjective judgments of relevant scholars. Led to charge of science as “mob psychology.” charge of science as “mob psychology.”

Kuhn later clarified his position, aruging that new Kuhn later clarified his position, aruging that new paradigms are accepted because they are more:paradigms are accepted because they are more: AccurateAccurate ConsistentConsistent Broad in scopeBroad in scope Simple and elegantSimple and elegant Fruitful of new research findings.Fruitful of new research findings.

Kuhn’s Conception of ScienceKuhn’s Conception of Science

For Kuhn, science is distinguished from pseudo-For Kuhn, science is distinguished from pseudo-science by the existence of a paradigm.science by the existence of a paradigm.

Progress only occurs within the set of Progress only occurs within the set of assumptions and rules that define what is worth assumptions and rules that define what is worth studying, what is known, and what particular studying, what is known, and what particular observations mean; that is, progress occurs only observations mean; that is, progress occurs only within paradigms.within paradigms.

Pre-science is found when multiple competing Pre-science is found when multiple competing approaches exist.approaches exist.

Ironically, during periods of revolutionary Ironically, during periods of revolutionary science, scientists are not really “doing” science.science, scientists are not really “doing” science.

CritiqueCritique Sociological and subjective nature of Sociological and subjective nature of

paradigm choice has left many paradigm choice has left many philosophers unsettled.philosophers unsettled.

Debate has focused on what objective Debate has focused on what objective processes and criteria may guide processes and criteria may guide paradigm choice.paradigm choice.

Popper, one of the great defenders of an Popper, one of the great defenders of an open society of debate and deliberation, open society of debate and deliberation, was deeply disturbed by Kuhn’s subjective was deeply disturbed by Kuhn’s subjective view of science and the apparent reliance view of science and the apparent reliance on consensus as the basis of knowledge.on consensus as the basis of knowledge.

LakatosLakatos The Methodology of Scientific Research The Methodology of Scientific Research

ProgrammesProgrammes (1970) (1970) Synthesizes Popper and Kuhn by focusing on Synthesizes Popper and Kuhn by focusing on

research programsresearch programs defined as a series of defined as a series of theories sharing a common “hard core” of theories sharing a common “hard core” of assumptions.assumptions.

Following Popper, Lakatos also emphasizes Following Popper, Lakatos also emphasizes falsification, but believes this only happens, falsification, but believes this only happens, following Kuhn, when a better theory emerges.following Kuhn, when a better theory emerges.

Argued “science” was the progressive Argued “science” was the progressive falsification of theory.falsification of theory.

LakatosLakatos““A scientific theory T is falsified if and only if A scientific theory T is falsified if and only if

another theory T’ has been proposed with the another theory T’ has been proposed with the following characteristics: (1) T’ has excess following characteristics: (1) T’ has excess empirical content over T: that is, it predicts empirical content over T: that is, it predicts novelnovel facts, that is, facts improbable in the light of, or facts, that is, facts improbable in the light of, or even forbidden, by T; (2) T’ explains the even forbidden, by T; (2) T’ explains the previous success of T, that is, all the unrefuted previous success of T, that is, all the unrefuted content of T is included (within the limits of content of T is included (within the limits of observational error) in the content of T’; and (3) observational error) in the content of T’; and (3) some of the excess content of T’ is some of the excess content of T’ is corroborated.”corroborated.”

LakatosLakatos

Thus, “no experiment, experimental report, Thus, “no experiment, experimental report, observation statement or well-corroborated low-observation statement or well-corroborated low-level falsifying hypothesis can lead to level falsifying hypothesis can lead to falsification. There is no falsification before the falsification. There is no falsification before the emergence of a better theory.” emergence of a better theory.” Unlike Popper, Lakatos is a sophisticated Unlike Popper, Lakatos is a sophisticated

falsificationist. falsificationist. Unlike Kuhn, Lakatos argues for an objective criterion Unlike Kuhn, Lakatos argues for an objective criterion

of progress: the prediction of new facts.of progress: the prediction of new facts.

Lakatos’ HeuristicsLakatos’ Heuristics For Lakatos, a research program is defined by For Lakatos, a research program is defined by

its key assumptions. These form the “hard core” its key assumptions. These form the “hard core” of the scientific research program (SRP).of the scientific research program (SRP).

This hard core is protected by a This hard core is protected by a negative negative heuristic,heuristic, the rule that forbids scholars working the rule that forbids scholars working within a SRP from contradicting the hard core.within a SRP from contradicting the hard core.

To deal with inconsistent evidence, Lakatos To deal with inconsistent evidence, Lakatos argues that SRPs develop a argues that SRPs develop a positive heuristicpositive heuristic or or “protective belt” of auxiliary hypotheses. “protective belt” of auxiliary hypotheses. Such auxiliary hypotheses can include additional Such auxiliary hypotheses can include additional

assumptions or restrictions on scope that make the assumptions or restrictions on scope that make the theory consistent with observed facts.theory consistent with observed facts.

Roughly equivalent to Kuhn’s problem solving.Roughly equivalent to Kuhn’s problem solving.

Progressive v. Degenerative SRPsProgressive v. Degenerative SRPs The key question is whether these auxiliary The key question is whether these auxiliary

hypotheses are progressive or degenerative. hypotheses are progressive or degenerative. If anomalies are reconciled with the hard core If anomalies are reconciled with the hard core

and produce novel facts that are then and produce novel facts that are then corroborated, the intra-paradigm problem shift is corroborated, the intra-paradigm problem shift is progressive.progressive.

If the amendment is ad hoc, the SRP is If the amendment is ad hoc, the SRP is degenerative.degenerative.

A degenerative SRP can, in conjunction with the A degenerative SRP can, in conjunction with the rise of a new theory, lead to falsification and the rise of a new theory, lead to falsification and the replacement of T by T’.replacement of T by T’.

Science and ProgressScience and Progress For Lakatos, as for Popper, the prediction For Lakatos, as for Popper, the prediction

of new facts is central to the concept of of new facts is central to the concept of science and scientific progress.science and scientific progress.

Contrary to Popper, however, for Lakatos Contrary to Popper, however, for Lakatos it is not falsification per se, but the ability it is not falsification per se, but the ability to uncover new facts that separates to uncover new facts that separates science from pseudo-science. science from pseudo-science.

So, what is “science”?So, what is “science”?

Theory must be founded on natural laws.Theory must be founded on natural laws. Theory must be falsifiable.Theory must be falsifiable. Theory must produce hypotheses that are Theory must produce hypotheses that are

corroborated by evidence.corroborated by evidence. Disconfirmation is “overblown.” Most Disconfirmation is “overblown.” Most

research progresses by solving puzzles research progresses by solving puzzles using the ideas within the hard core of a using the ideas within the hard core of a research program. research program. Rewards go to those who solve particularly Rewards go to those who solve particularly

hard puzzles.hard puzzles.

Conditions of Science continuedConditions of Science continued Predictions of new facts that are then Predictions of new facts that are then

corroborated by evidence is the ideal.corroborated by evidence is the ideal. Scientific revolutions or paradigm shifts Scientific revolutions or paradigm shifts

are rare. Challenging or amending the are rare. Challenging or amending the hard core is not what science is usually hard core is not what science is usually about.about.

Changing “how we think about the Changing “how we think about the universe” occurs at several levels, from universe” occurs at several levels, from resolving particularly difficult puzzles to resolving particularly difficult puzzles to developing a new paradigm.developing a new paradigm.

Political science is on the cusp Political science is on the cusp of becoming a science.of becoming a science.

American politics is probably already a science, American politics is probably already a science, if by that we mean (following Kuhn and Lakatos) if by that we mean (following Kuhn and Lakatos) that there is a shared paradigm or SRP (largely that there is a shared paradigm or SRP (largely rational choice). Research is conducted with rational choice). Research is conducted with broad agreement on assumptions, what broad agreement on assumptions, what constitutes knowledge, what are the puzzles constitutes knowledge, what are the puzzles worth solving.worth solving.

International relations and comparative politics International relations and comparative politics are still pre-scientific, but well on their way to are still pre-scientific, but well on their way to becoming a science by adopting the hard core of becoming a science by adopting the hard core of rational choice theory as well.rational choice theory as well.

Lessons for Your ResearchLessons for Your Research Since science is a social enterprise, your Since science is a social enterprise, your

work counts only by how it is received by work counts only by how it is received by the scientific community. This reception is the scientific community. This reception is partly subjective. You must argue your partly subjective. You must argue your case in the face of sometimes conflicting case in the face of sometimes conflicting and ambiguous criteria.and ambiguous criteria.

Even though we may agree on the Even though we may agree on the conditions that make a theory “better,” we conditions that make a theory “better,” we can still disagree and, therefore, argue can still disagree and, therefore, argue over which particular theory best fits those over which particular theory best fits those conditions.conditions.

Valid Scientific ArgumentsValid Scientific Arguments You are solving a genuine and significant You are solving a genuine and significant

puzzle within the field.puzzle within the field. The evidence corroborates your theory The evidence corroborates your theory

and hypotheses. and hypotheses. This is a question of research design. The This is a question of research design. The

better your research design, the stronger your better your research design, the stronger your argument will be.argument will be.

Your amendment to the hard core is Your amendment to the hard core is progressive. Resolving the puzzle progressive. Resolving the puzzle uncovers additional implications that are uncovers additional implications that are also empirically corroborated.also empirically corroborated.

Scientific Arguments continuedScientific Arguments continued

Since multiple theories may exist in the Since multiple theories may exist in the protective belt or positive heuristic, your protective belt or positive heuristic, your theory is more elegant, broader in the theory is more elegant, broader in the range of phenomena its predicts/explains, range of phenomena its predicts/explains, and supported better by the evidence than and supported better by the evidence than its plausible rivals.its plausible rivals.

In rare cases, you have sufficiently altered In rare cases, you have sufficiently altered the hard core that you have created a new the hard core that you have created a new research program.research program.

Guide to Writing a Guide to Writing a Scientific PaperScientific Paper

The Point (one and only one): one sentence.The Point (one and only one): one sentence. The Argument: the point is your conclusion here.The Argument: the point is your conclusion here. The Purpose: The Purpose:

An argument: demonstrate the plausibility of your An argument: demonstrate the plausibility of your assumptions and the deductive validity of your conclusionassumptions and the deductive validity of your conclusion

An empirical paper: exploration, counterexamples, An empirical paper: exploration, counterexamples, correlation, causal testcorrelation, causal test

Steps can be approached through the scientific Steps can be approached through the scientific method:method: ObserveObserve Explain/hypothesizeExplain/hypothesize Construct a testConstruct a test Draw inferencesDraw inferences UpdateUpdate

These steps are distinct from the process of writing These steps are distinct from the process of writing your paperyour paper

Writing the PaperWriting the Paper

1) Introduction (1 page or 3 1) Introduction (1 page or 3 paragraphs): states puzzle, paragraphs): states puzzle, summarizes two sides to debate, summarizes two sides to debate, makes the point.makes the point.

2) Literature Review (2 pages or less): 2) Literature Review (2 pages or less): outlines the two sides to debate, the outlines the two sides to debate, the major issues, and why you take one major issues, and why you take one side or the other.side or the other.

3) Your Argument/Explanation: state 3) Your Argument/Explanation: state your argument and core analogy.your argument and core analogy.

Writing the PaperWriting the Paper4) Your constructs and construct validity.4) Your constructs and construct validity.5) Your test/correlation/exploration: state 5) Your test/correlation/exploration: state

your research design explicitly and your research design explicitly and clearly.clearly.

6) Describe your data.6) Describe your data.7) Discuss potential econometric concerns 7) Discuss potential econometric concerns

and resolutions.and resolutions.8) Present results, interpreting them in 8) Present results, interpreting them in

light of theory/hypotheses. light of theory/hypotheses. 9) Conclusion: discuss external validity, 9) Conclusion: discuss external validity,

with attention to the limits of your with attention to the limits of your findings.findings.

Final SuggestionsFinal Suggestions Cite the major pieces in the literature, be Cite the major pieces in the literature, be

generous.generous. Proofread. Style, punctuation, spelling Proofread. Style, punctuation, spelling

matters!matters! Share with colleagues in ever enlarging Share with colleagues in ever enlarging

circles. Feedback is important because we circles. Feedback is important because we don’t know which analogies, presentation don’t know which analogies, presentation strategies, etc., will work. After getting strategies, etc., will work. After getting reactions from friends and mentors, distribute reactions from friends and mentors, distribute more widely to participants in the debate.more widely to participants in the debate.

Criticism is always helpful – be grateful that Criticism is always helpful – be grateful that someone took the time to read and comment someone took the time to read and comment on your work.on your work.