Scientific Progress and Its Problems Verification Falsification or

Scientific Progress and Its Problems Verification, Falsification or What? Lecture 3 1

Introduction The aim of the lecture is n To present the major conceptions of scientific growth n To discuss their respective strong and weak points. Lecture 3 2

Main Topics n n The inductivist model of science Karl Popper’s falsificationism Thomas Kuhn’s structural criterion of science Imre Lakatos, sophisticated falsificationism, and research programmes Lecture 3 3

Main Topics n n n The abandonment of the search for ‘the’ method (Feyerabend) Larry Laudan’s research traditions How to judge the value of a scientific theory? Lecture 3 4

The Inductivist Model of Science (1) n n The facts are observed and recorded. The observed and recorded facts are analysed, compared and categorized. Lecture 3 5

The Inductivist Model of Science (2) n n From this analysis of the facts, generalizations are inductively drawn as to the relations (empirical regularities) between them. Further research is inductive as well as deductive, employing inferences from previously established generalizations. Lecture 3 6

Figure 1: the Inductivist Model Lecture 3 7

Popper’s Falsificationism (1) n Not verification, but falsification ¡ n Reason: the classical problem of induction Observation is always affected by prior theoretical and conceptual commitments: ¡ ¡ it is guided by and presupposes theory (the socalled searchlight theory of knowledge) observation is thus theory-laden Lecture 3 8

Popper’s Falisficationism (2) n n Theories cannot be established as true in the light of observational evidence. Theories are constructed as speculative and tentative conjectures freely created by the human intellect in an attempt to overcome problems encountered by previous theories to give an adequate account of some aspects of the world. ¡ That is why Popper’s epistemology is commonly labelled ‘critical rationalism’. Lecture 3 9

Popper’s Falisficationism (3) n n Once proposed, speculative theories are to be rigorously and ruthlessly tested by observation and experiment Theories that conflict with empirical evidence must be eliminated (falsified) and replaced by new theories Lecture 3 10

Popper’s Falisficationism (4) n n Science thus progresses by trial and error, by conjectures and refutations Only the fittest theories survive and are tentatively and temporarily accepted Lecture 3 11

Popper’s Falisficationism (5) n A theory can never be said to be true ¡ n Of a theory it can only be said that it is the best available in the sense that is better than anything that has come before – at least for the time being. As a consequence ¡ ¡ there is no certainty in science scientific knowledge is always tentative. Lecture 3 12

Kuhn’s Structural Criterion of Science (1) n n Scientists do not in fact falsify theories in the ‘instant’ way specified by Popper While at the level of empirical hypotheses Popperian falsificationism may operate, this cannot be maintained at the level of broader theoretical structures or the evolution of science as a whole Lecture 3 13

Kuhn’s Structural Criterion of Science (2) n According to Kuhn scientific evolution should be understood as the development of complex structures of theories or, as he calls them, ‘paradigms’ Lecture 3 14

Kuhn’s Structural Criterion of Science (3) n n The central concept of Kuhn’s epistemology is ‘paradigm’. Masterman identifies three basic concepts within Kuhn’s notion of paradigm: ¡ ¡ ¡ the ‘metaphysical’ paradigm, the ‘sociological’ paradigm, and. the ‘artefact’ paradigm. Lecture 3 15

Kuhn’s Structural Criterion of Science (4) n The metaphysical paradigm involves the ontological elements of a theory, namely those assumptions that affect the way in which man views the world and his place in it. Lecture 3 16

Kuhn’s Structural Criterion of Science (5) n The sociological paradigm refers to a concrete scientific achievement that functions as a model or framework within which scientific research is conducted. Lecture 3 17

Thomas Kuhn’s Structural Criterion of Science (6) n Finally, the artefact paradigm concerns a distinct set of tools, techniques or instrumentation that are considered relevant to he validation of scientific knowledge. Lecture 3 18

Thomas Kuhn’s Structural Criterion of Science (7) n n n Normal science Crisis Revolutionary science ‘Gestalt’ switch New period of normal science ¡ New paradigm is incommensurable with previous one Lecture 3 19

Thomas Kuhn’s Structural Criterion of Science (8) n A paradigm will never be replaced unless a ‘less problematic or better’ one comes around Lecture 3 20

Thomas Kuhn’s Structural Criterion of Science (9) n Within this general process of development of science Kuhn stresses: ¡ ¡ the importance of the scientific community the role of extra-scientific elements Lecture 3 21

Thomas Kuhn’s Structural Criterion of Science (9) n n This implies a conception of science as a social activity Epistemology is an empirical science Lecture 3 22

Lakatos, Sophisticated Falsificationism, and Research Programmes (1) Naïve falsificationism n A theory is falsified by an observational statement that conflicts with it Lecture 3 23

Lakatos, Sophisticated Falsificationism, and Research Programmes (2) Sophisticated falsificationism n A theory T 1 is falsified if another theory T 2 has been proposed with the following characteristics: ¡ ¡ ¡ T 2 has excess empirical content over T 1: that is, if it predicts novel facts T 2 explains the empirical content of T 1 Some of the excess content of T 2 is corroborated Lecture 3 24

Lakatos, Sophisticated Falsificationism, and Research Programmes (3) Research programmes n Theories are part of broader structures, which Lakatos calls “research programmes” n Within such a programme theories develop in a dynamic way Lecture 3 25

Lakatos, Sophisticated Falsificationism, and Research Programmes (4) n A theory that is shown to be inadequate is replaced by a better one but typically one which belongs to the same family ¡ We have a sequence of theories, T(1), T(2), T(3) and so on, each of which explains more than its predecessor and thus supersedes it Lecture 3 26

Lakatos, Sophisticated Falsificationism, and Research Programmes (5) n Such a sequence of interrelated theories is what Lakatos calls a scientific research programme Lecture 3 27

Lakatos, Sophisticated Falsificationism, and Research Programmes (6) n The family relationship is carried on by the negative heuristic or hard core, which will not be doubted, at least during the course of the programme. Lecture 3 28

Lakatos, Sophisticated Falsificationism, and Research Programmes (7) n Whenever observations do not fit smoothly into this framework and objections are raised the rational response is n n not to forego the hard-core assumptions but to protect them by a set of auxiliary hypotheses that ¡ ¡ aim at increasing the predictive power of the programme and in this way ‘protect’ the hard core Lecture 3 29

Lakatos, Sophisticated Falsificationism, and Research Programmes (8) n The part of the research programme containing the auxiliary hypotheses is thus called the protective belt or positive heuristic ¡ It indicates what needs to be done in order to increase the explanatory and predictive power of the programme. Lecture 3 30

Lakatos, Sophisticated Falsificationism, and Research Programmes (9) When is a research programme falsified? n A research programme R 1 is falsified when there is an alternative research programme R 2 that 1. 2. can explain and predict as much as research programme R 1 does predicts novel facts, some of which are corroborated Lecture 3 31

Feyerabend: the Abandonment for the Search of ‘The’ Method n Feyerabend’s key points are: ¡ ¡ All methods have their limitations ‘The’ method of science does not exist Therefore, the most reasonable position is that of methodological pluralism The importance of creativity in science: anything goes Lecture 3 32

Laudan’s Research Traditions (1) n n Laudan argues that Lakatos’ criteria for falsifying research programmes, namely theoretical and empirical progressiveness, are too strict and do not stand the test of the history of science. In essence his position boils down to a pragmatic interpretation and integration of Kuhnian and Lakatosian concepts. Lecture 3 33

Laudan’s Research Traditions (2) n A research tradition is a set of general assumptions about ¡ ¡ the entities and the processes in a domain of study (ontology), and about the appropriate principles and methods to be used for investigating the problems and constructing theories in that domain (epistemology and methodology). Lecture 3 34

Laudan’s Research Traditions (3) n Contrary to Lakatos these general assumptions (hard core assumptions if you wish) may change Lecture 3 35

Laudan’s Research Traditions (4): Empirical and Conceptual Problems n For Laudan science is ¡ ¡ not only about empirical problems but also about conceptual problems Lecture 3 36

Laudan’s Research Traditions (5): Nature of Empirical Problems n n Empirical problems are problems about the world Empirical problems are theory-laden as they are generated within a certain theoretical structure Lecture 3 37

Laudan’s Research Traditions (6): Nature of Empirical Problems n He distinguishes three kind of empirical problems: ¡ ¡ ¡ solved problems unsolved problems anomalous problems Lecture 3 38

Laudan’s Research Traditions (7): Nature of Conceptual Problems n n Internal conceptual problems: when T exhibits certain internal inconsistencies, or when its basic categories of analysis are vague and unclear External conceptual problems: when T is in conflict with another theory, T’, which proponents of T rationally believe to be well founded Lecture 3 39

Laudan’s Research Traditions (8): Sources of Conceptual Problems n n n Intra-scientific difficulties Normative difficulties Worldview (ontological) difficulties Lecture 3 40

Laudan’s Research Traditions (9): Core Assumptions n n The solved problem – empirical or conceptual – is the base of scientific progress (pragmatism) The aim of science is to maximise the scope of solved empirical problems, while minimising the scope of anomalous and conceptual problems Lecture 3 41

Laudan’s Research Traditions (10): Evaluation of Theories n The first and essential test for any theory is whether ¡ it provides acceptable answers to interesting questions: n whether, in other words, it provides satisfactory solutions to important problems Lecture 3 42

Larry Laudan’s Research Traditions (11): Evaluation of Theories n In appraising the merits of theories, it is more important to ask ¡ ¡ n whether they constitute adequate solutions to significant problems than it is to ask whether they are “true”, “corroborated”, “well confirmed” or otherwise justifiable within the framework of contemporary epistemology This is a kind of judgemental rationalism (Bhaskar) Lecture 3 43

Larry Laudan’s Research Traditions (11): Evaluation of Theories n The overall effectiveness of a theory is determined by n n assessing the number and importance of the empirical problems, which theory solves, and deducting thereof the number and importance of the anomalies and conceptual problems, which theory generates, determine the overall effectiveness of a theory Lecture 3 44

How to Judge the Value of a Scientific Theory or Model? A Few Rules of Thumb n n To which degree does it tackle the problems for which it was designed, compared to others that are applicable to the same problems? To what extent can one relax its assumptions and still retain a coherent model? Lecture 3 45

How to Judge the Value of a Scientific Theory or Model? A Few Rules of Thumb n n To which extent events that do not conform to the model’s predictions can be explained by a manageable examination of its conditions? To which extent it is able to generate propositions about the real world that are not attainable through simple observation and common sense? Lecture 3 46

How to Judge the Value of a Scientific Theory or Model? A Few Rules of Thumb n To which extent does it lead to the construction of a new and better model? Lecture 3 47