Science and Scientific Discovery

1. Science and Scientific Discovery

2. Time Series Test William at 18 months, after first Christmas William at 6 months, before 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.

3. What Counts as Scientific Knowledge? • We “know” many things: • The sun rises in the morning • Its best to treat others as you want to be treated • Water boils at 100c • The working class is exploited • Wars are caused by bargaining failures • Which of these statements count as scientific? • Philosophy of Science is a theory of knowledge (ontology) and a theory about the progress of knowledge (epistemology).

4. Science and Its Rivals • Primary divide between non-science and science: • Science explains outcomes in terms of natural laws, non-science permits supernatural causes. • Secondary divide between science and pseudo-science. • Science is falsifiable, pseudo-science is not.

5. Popper • Science and Pseudo-science • Many systems of thought share a similar structure: premises are taken as given and implications are derived logically. • This is true for theories, as well as ideologies. • All can be useful guides for human behavior. • The key difference between science and pseudo-science (and non-science) is the criterion of falsifiability. • Theories are open to potential refutation. Ideologies (and religions) are not.

6. Hypothetico-Deductive Reasoning • Falsifiability implies that deduction is the only valid form of scientific reasoning. • Induction cannot be falsified. Correlation between X and Y stands as “fact.” • Thus, much of what scientists do – that is, observe – was classified as non-science. • Also implies that the task of science is to disconfirm theories. • Theories can only be supported. Valid theories are those not yet proven false. • Scientists immediately reject theories once disconfirming evidence is found (naïve falsification).

7. Critique • Principle of falsification still important. • Tests still aim, in part, to disconfirm theories. • But Popper’s criterion and its implications did not embody what people who identify themselves as scientists actually do. • Scientists typically pursue confirming experiments. • Scientists do not reject theories because they encounter some disconfirming evidence. • Steven Weinberg (Nobel in Physics): there “is no theory that is not contradicted by some experiment.”

8. Kuhn • Structure of Scientific Revolutions (1962). • Paradigm is a set of generally (if not universally) shared assumptions that underlay one or more theories. • Represented in “textbook” version of the field. • Paradigm initiates new entrants to the field into the dominant set of ideas.

9. Normal Science • Normal Science: occurs within a paradigm. • Does not search for disconfirming evidence or anomalies. • Ambition is to extend the paradigm to already known and new phenomena, to explain more phenomena in terms of the theory. • Normal science is puzzle solving according to the rules (assumptions) laid down by the paradigm. • Phenomena that do not fit the paradigm are often not even “seen.”

10. Revolutionary Science • In extending the paradigm, scientists encounter unresolved puzzles or anomalies. • Accumulation of anomalies eventually brings the paradigm into question, but does not lead to the falsification or rejection of the paradigm. • Revolution occurs only when a new and better theory able to resolve the anomalies arises. • Science does not proceed by naïve falsification but by the development of better theory.

11. Role of Assumptions • Assumptions are never “true.” They embody the analogy that informs the theory. Theories are intended to capture the “essence” of a particular setting/event/process. • In normal science, assumptions are treated as unproblematic. They “make sense” given the utility of the prevailing paradigm. • In revolutions, assumptions are called into question and some or all are overthrown. Previous assumptions are now regarded as naïve.

12. Paradigm Change • Science is an inherently social phenomena. “Knowledge” depends on the assent of the community of scholars. • Choice of a new paradigm is dependent on the subjective judgment of the relevant community of scientists. • Tests, anomalies, and explanations only make sense in terms of a particular paradigm. Because they possess incommensurable assumptions, difficult to have “head-to-head” competitions between theories from different paradigms. • There are few decisive tests, since the very meaning of the test typically differs across paradigms. • Adoption of a paradigm is an “all-or-nothing” affair.

13. Paradigm Change continued • Most important, the full problem-solving abilities of new paradigm are not yet demonstrated at the time the paradigm is adopted. • Choice of paradigm, then, is a collective exercise based on beliefs and, in part, on subjective judgments of relevant scholars. Led to charge of science as “mob psychology.” • Kuhn later clarified his position, aruging that new paradigms are accepted because they are more: • Accurate • Consistent • Broad in scope • Simple and elegant • Fruitful of new research findings.

14. Kuhn’s Conception of Science • For Kuhn, science is distinguished from pseudo-science by the existence of a paradigm. • Progress only occurs within the set of assumptions and rules that define what is worth studying, what is known, and what particular observations mean; that is, progress occurs only within paradigms. • Pre-science is found when multiple competing approaches exist. • Ironically, during periods of revolutionary science, scientists are not really “doing” science.

15. Critique • Sociological and subjective nature of paradigm choice has left many philosophers unsettled. • Debate has focused on what objective processes and criteria may guide paradigm choice. • Popper, one of the great defenders of an open society of debate and deliberation, was deeply disturbed by Kuhn’s subjective view of science and the apparent reliance on consensus as the basis of knowledge.

16. Lakatos • The Methodology of Scientific Research Programmes (1970) • Synthesizes Popper and Kuhn by focusing on research programs defined as a series of theories sharing a common “hard core” of assumptions. • Following Popper, Lakatos also emphasizes falsification, but believes this only happens, following Kuhn, when a better theory emerges. • Argued “science” was the progressive falsification of theory.

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

18. Lakatos • Thus, “no experiment, experimental report, observation statement or well-corroborated low-level falsifying hypothesis can lead to falsification. There is no falsification before the emergence of a better theory.” • Unlike Popper, Lakatos is a sophisticated falsificationist. • Unlike Kuhn, Lakatos argues for an objective criterion of progress: the prediction of new facts.

19. Lakatos’ Heuristics • For Lakatos, a research program is defined by its key assumptions. These form the “hard core” of the scientific research program (SRP). • This hard core is protected by a negative heuristic, the rule that forbids scholars working within a SRP from contradicting the hard core. • To deal with inconsistent evidence, Lakatos argues that SRPs develop a positive heuristic or “protective belt” of auxiliary hypotheses. • Such auxiliary hypotheses can include additional assumptions or restrictions on scope that make the theory consistent with observed facts. • Roughly equivalent to Kuhn’s problem solving.

20. Progressive v. Degenerative SRPs • The key question is whether these auxiliary hypotheses are progressive or degenerative. • If anomalies are reconciled with the hard core and produce novel facts that are then corroborated, the intra-paradigm problem shift is progressive. • If the amendment is ad hoc, the SRP is degenerative. • A degenerative SRP can, in conjunction with the rise of a new theory, lead to falsification and the replacement of T by T’.

22. Science and Progress • For Lakatos, as for Popper, the prediction of new facts is central to the concept of science and scientific progress. • Contrary to Popper, however, for Lakatos it is not falsification per se, but the ability to uncover new facts that separates science from pseudo-science.

23. So, what is “science”? • Theory must be founded on natural laws. • Theory must be falsifiable. • Theory must produce hypotheses that are corroborated by evidence. • Disconfirmation is “overblown.” Most research progresses by solving puzzles using the ideas within the hard core of a research program. • Rewards go to those who solve particularly hard puzzles.

24. Conditions of Science continued • Predictions of new facts that are then corroborated by evidence is the ideal. • Scientific revolutions or paradigm shifts are rare. Challenging or amending the hard core is not what science is usually about. • Changing “how we think about the universe” occurs at several levels, from resolving particularly difficult puzzles to developing a new paradigm.

25. Political science is on the cusp of becoming a science. • American politics is probably already a science, if by that we mean (following Kuhn and Lakatos) that there is a shared paradigm or SRP (largely rational choice). Research is conducted with broad agreement on assumptions, what constitutes knowledge, what are the puzzles worth solving. • International relations and comparative politics are still pre-scientific, but well on their way to becoming a science by adopting the hard core of rational choice theory as well.

26. Lessons for Your Research • Since science is a social enterprise, your work counts only by how it is received by the scientific community. This reception is partly subjective. You must argue your case in the face of sometimes conflicting and ambiguous criteria. • Even though we may agree on the conditions that make a theory “better,” we can still disagree and, therefore, argue over which particular theory best fits those conditions.

27. Valid Scientific Arguments • You are solving a genuine and significant puzzle within the field. • The evidence corroborates your theory and hypotheses. • This is a question of research design. The better your research design, the stronger your argument will be. • Your amendment to the hard core is progressive. Resolving the puzzle uncovers additional implications that are also empirically corroborated.

28. Scientific Arguments continued • Since multiple theories may exist in the protective belt or positive heuristic, your theory is more elegant, broader in the range of phenomena its predicts/explains, and supported better by the evidence than its plausible rivals. • In rare cases, you have sufficiently altered the hard core that you have created a new research program.

29. Guide to Writing a Scientific Paper • The Point (one and only one): one sentence. • The Argument: the point is your conclusion here. • The Purpose: • An argument: demonstrate the plausibility of your assumptions and the deductive validity of your conclusion • An empirical paper: exploration, counterexamples, correlation, causal test • Steps can be approached through the scientific method: • Observe • Explain/hypothesize • Construct a test • Draw inferences • Update • These steps are distinct from the process of writing your paper

30. Writing the Paper 1) Introduction (1 page or 3 paragraphs): states puzzle, summarizes two sides to debate, makes the point. 2) Literature Review (2 pages or less): outlines the two sides to debate, the major issues, and why you take one side or the other. 3) Your Argument/Explanation: state your argument and core analogy.

31. Writing the Paper 4) Your constructs and construct validity. 5) Your test/correlation/exploration: state your research design explicitly and clearly. 6) Describe your data. 7) Discuss potential econometric concerns and resolutions. 8) Present results, interpreting them in light of theory/hypotheses. 9) Conclusion: discuss external validity, with attention to the limits of your findings.

32. Final Suggestions • Cite the major pieces in the literature, be generous. • Proofread. Style, punctuation, spelling matters! • Share with colleagues in ever enlarging circles. Feedback is important because we don’t know which analogies, presentation strategies, etc., will work. After getting reactions from friends and mentors, distribute more widely to participants in the debate. • Criticism is always helpful – be grateful that someone took the time to read and comment on your work.