1. Philosophy of Science An Introduction

2. Preface These slides are based on BOOK I at: www.philsci.com (with a PowerPoint display) and on the e-books: Philosophy of Science: An Introduction and Twentieth-Century Philosophy of Science: A History (BOOK I) This slide selection is not a display of all of the book’s sections. The user may edit (add, modify or delete) these slides as desired.

3. Philosophy of Science An Introduction The ebook

4. Twentieth Century Philosophy of Science The ebook and the web site www.philsci.com (with free downloads)

5. CONTENTS Chapter I Overview Chapter II Three Modern Philosophies Chapter III Philosophy of Language Chapter IV Functional Topics in Basic-Science

6. Chapter I Overview

7. Section 1.01 Introduction Basic Science –Creates of new scientific language, e.g.: New Theories New Laws New Explanations Applied Science –Uses tested and nonfalsified scientific explanations to change the real world, e.g.: New Technologies New Social Policies New Therapies

8. Section 1.01 Introduction Preamble: –Both successful basic science and contemporary philosophy of science are pragmatic.

9. Section 1.01 Introduction Aim of contemporary philosophy of science –The aim of contemporary pragmatist philosophy of science is to discover principles –that explain successful practices of basic-science research –by investigating episodes in the history of successful science, –in order to advance contemporary science by application of the principles.

10. Section 1.02 Introduction Computational philosophy of science: –Computational philosophy of science is the design, development and application of computer systems that mechanize and thus proceduralize productive basic-research practices in the sciences. –Application of discovery systems gives the philosopher of science a practical and consequential role in basic-scientific research.

11. Section 1.03 Introduction Perspectives on language: –Object language includes most of everyday discourse together with the language of the sciences, and is about the nonlinguistic domains of reality including domains that the particular sciences investigate. –Metalanguage is language describing language.

12. Section 1.04 Introduction Dimensions of all language: –Syntax. The structure of language. –Semantics. The meanings associated with syntax. –Ontology. The real world as described by semantics. –Pragmatics. The use of language in science.

13. Section 1.04 Introduction Dimensions are inclusively related: Pragmatics Semamtics Ontology Syntax

14. Section 1.05 Introduction Functional topics in basic research: –Aim of Science. The institutionalized aim of basic research. –Discovery. The development of new theories. –Criticism. The criteria for evaluating theories. –Explanation. The nature of scientific explanation.

15. Section 1.06 Introduction Modern philosophies of science: –Romanticism. A philosophy for social and cultural sciences. –Positivism. A philosophy for all sciences based on Newtonian physics. –Contemporary pragmatism. A philosophy for all empirical sciences based on quantum theory.

16. Section 1.05 - 1.06 Introduction Relation of the three philosophies and the four topics:

17. Section 1.05 - 1.06 Introduction Meanings of common metalinguistic terms differ among the philosophies

18. Chapter II Three Modern Philosophies

19. Section 2.01 Introduction Romanticism - Aim of Science: –Romantics maintain that there is a fundamental divide between sciences of nature and sciences of culture. –The aim of the social sciences, the sciences of culture, is “interpretative understanding” of “human action”, by which is meant explanation of social interaction in terms of subjective mental states – ideas and motives – that are culturally shared by members of social groups.

20. Section 2.01 Introduction Romanticism - Discovery: –Romantics define “theory” as language describing subjective mental states, notably culturally shared ideas and motivations. –The discovery of theory in social science may involve the social scientist’s introspective reflection on her/his own motivations that are “convincing” to her/ him for understanding by imputation the subjective mental states of the social members.

21. Section 2.01 Introduction Romanticism - Criticism: –The romantic criterion for criticism is “interpretative understanding” of conscious motivations, which are deemed to be the underlying “causal mechanisms” of observed human action. Social theory must “make sense” or be “convincing” in the particular investigator’s own subjective personal or vicarious experience.

22. Section 2.01 Introduction Romanticism - Explanation: –Romantics maintain that only “theory” that describes subjective motives can “explain” conscious human action. –Motives are the causal factors or “mechanisms” identified in “theoretical” explanations.

23. Section 2.02 Introduction Positivism - Aim of Science: –The positivist view of the aim of science is to produce explanations having objectivity grounded in language describing observations.

24. Section 2.02 Introduction Positivism - Discovery: –Positivists believed that empirical laws are inferentially discovered by inductive generalization based on repeated observations. –Positivists believed that theories are the discovered by creative imagination, but left unexplained the creative process of developing theories.

25. Section 2.02 Introduction Positivism - Criticism: –The criterion for criticism is publicly accessible observation expressed in language containing only “observation terms”. –Empirical laws indirectly and tentatively warrant theories, when the laws can be logically derived from the theories.

26. Section 2.02 Introduction Positivism - Explanation: –According to Hempel’s “covering-law” thesis of explanation, predictions of observable events are derived deductively from observation-language statements together with “covering” universal empirical laws. This form has also been called the “deductive- nomological model” of explanation.

27. Section 2.03 Introduction Pragmatism - Three fundamental theses were formulated in the 1920’s by the Nobel laureate physicists Werner Heisenberg and Albert Einstein, who anticipated the contemporary pragmatism in academic philosophy: –Thesis I: Relativized semantics. –Thesis II: Empirical underdetermination. –Thesis III: Ontological relativity.

28. Section 2.03 Introduction Thesis I: Relativized semantics. –In 1925 Einstein told Heisenberg “the theory decides what the physicist can observe”. His view of observation contradicts the fundamental positivist thesis that there is a dichotomous semantical separation between observation language and theory language.

29. Section 2.03 Introduction Thesis II: Empirical underdetermination. –Empirical underdetermination refers to the limited ability of the semantics of language at any given time to signify reality. –Examples of empirical underdetermination: Conceptual vagueness, which can be reduced but never completely eliminated. Measurement has error, which can be reduced but never completely eliminated.

30. Section 2.03 Introduction Thesis III: Ontological relativity. –Heisenberg wrote that the “decisive step” in Einstein’s special theory of relativity consisted of Einstein’s taking the relativity theory realistically, thus letting his relativity theory characterize the physically real, i.e., physical ontology. –Heisenberg imitated Einstein in his Copenhagen interpretation of quantum theory.

31. Section 2.03 Introduction Pragmatism - Aim of Science : –The aim of basic science is explanation. Explanations contain laws from which descriptions of individual events are logically derived. Laws are former theories that have been tested and not falsified.

32. Section 2.03 Introduction Pragmatism - Discovery: –“Theory” and “observation” language are defined pragmatically instead of semantically. –The pragmatics of theory is empirical testing to discover laws. Theory language is proposed for testing. Test-design language is presumed for testing.

33. Section 2.03 Introduction Pragmatism - Discovery: –Contemporary pragmatists individuate theories semantically. –Two theory expressions are different theories: if the expressions have different test designs so they identify different subjects, or if the expressions make contrary claims about the same subject as defined by the same test design.

34. Section 2.03 Introduction Pragmatism - Discovery: –Contemporary pragmatism is consistent with computerized discovery systems, which aim to proceduralize development of new theories, in order to advance contemporary science.

35. Section 2.03 Introduction Pragmatism - Criticism: –Contemporary pragmatists recognize the empirical criterion as the only valid decision criterion that yields scientific progress. –They recognize the nontruth-functional hypothetical-conditional form of statement-schema for expressing proposed theories. –They recognize the modus tollens falsifying argument for empirical testing of the theories.

36. Section 2.03 Introduction Pragmatism - Explanation: –Explanation describes the occurrence of individual events as caused according to law statements by the occurrence of other described events.

37. Section 2.03 Introduction Pragmatism - Explanation: –Pragmatists recognize the nontruth-functional hypothetical-conditional form of statement- schema for expressing proposed theories. –They recognize the modus tollens falsifying argument for empirical testing of the theories.

38. Chapter III Philosophy of Language

39. Section 3.01 Introduction Types of Linguistic Analysis: –Synchronic - view at a point in time like a photo. –Diachronic: Comparative static - view at two points of time like “before” and “after” photos. Dynamic - view through time like a motion picture.

40. Section 3.03 Introduction Dimensions of all language: –Syntax. The structure of language. –Semantics. The meanings associated with syntax. –Ontology. The real world as described by semantics. –Pragmatics. The use of language in science.

41. Section 3.04 Introduction Syntactical Dimension: –Syntax is the system of symbols in linguistic expressions considered in abstraction from the meanings associated with the symbols.

42. Section 3.05 Introduction Syntactical formation rules: –Expressions in metalanguage that regulate construction of grammatical sentences out of more elementary symbols. E.g., combining words into sentences.

43. Section 3.05 Introduction Generative grammar discovery system: –A system that applies formation rules to more elementary syntactical symbols, to construct grammatical sentences or well-formed mathematical expressions that are new theories. –A discovery system is a computerized generative grammar that generates and may empirically test scientific theories as its output.

44. Section 3.07 Introduction Logical quantification in mathematics –Mathematical expressions in science are universally quantified, when descriptive variables have no associated numerical values, and are particularly quantified when numeric values are associated empirically with any of the expression’s descriptive variables.

45. Section 3.08 Introduction Semantical Dimension: –Semantics is the meanings associated with syntactical symbols.

46. Section 3.10 Introduction Natural vs artifactual semantics: –Naturalistic semantics - the meanings of descriptive terms are causally and fully determined ostensively by perception. –Artifactual semantics - the meanings of descriptive terms are determined contextually in universally quantified statements believed true. Then ontology, semantics and belief are mutually determined.

47. Section 3.11 Introduction Romantic semantics: –The semantics for the social sciences explaining human action must include description of the culturally shared subjective meaning that the human action has for the social-group members. Romantics call the resulting subjective meaning “interpretative understanding”.

48. Section 3.12 Introduction Positivist semantics: –Observation semantics is causally determined by nature and acquired ostensively by perception. The ostensively acquired meanings of descriptive terms used for reporting observations are primitive, simple and fully determined by nature and perception.

49. Section 3.12 Introduction Positivist semantical theses: –Meaning invariance. –Analytic-synthetic dichotomy. –Observation-theory dichotomy.

50. Section 3.13 Introduction Meaning invariance thesis: –Nature determines the semantics of observation terms to be the same for all persons who have the same perceptual stimuli that occasioned their having acquired their semantics ostensively in the same circumstances.

51. Section 3.14 Introduction Analytic-synthetic dichotomy thesis: –Analytic statements are true a priori due to the interdependent meanings of the constituent terms. E.g., “All bachelors are unmarried.” –Synthetic statements are true a posteriori due to the independent meanings of the constituent terms. E.g., “All ravens are black.”

52. Section 3.15 Introduction Observation-theory dichotomy thesis: –Observation terms on the positivist view reference or describe observable entities and phenomena. E.g., “raven” and “black”. –Theoretical terms on the positivist view do not reference or describe observable entities or phenomena. E.g., “electron” and “virus”.

53. Section 3.18 Introduction Pragmatists reject the observation- theory dichotomy. –Pragmatists reject natural semantics for identifying language used for observational reporting. So-called theoretical terms are merely more empirically underdetermined than so-called observation terms. Thus there is no qualitatively separate subclass of theoretical terms.

54. Section 3.19 Introduction Pragmatists reject meaning invariance. –The semantics of every descriptive term is determined by the term’s linguistic context consisting of a set of universally quantified statements believed to be true, such that a change in any of those contextual beliefs changes some component parts of the constituent terms’ meanings. Thus a change in any of those beliefs changes some parts of the constituent terms’ meanings.

55. Section 3.19 Introduction Pragmatists reject meaning invariance. –In science the linguistic context consisting of universally quantified statements believed to be true may include both theories and law statements including test-design statements, which jointly contribute to the semantics of their shared constituent descriptive terms.

56. Section 3.20 Introduction Pragmatists reject the analytic- synthetic dichotomy. –All universally quantified affirmations believed to be true are both analytic and synthetic. They may be called “analytical hypotheses”.

57. Section 3.21 Introduction Semantical rule: –A semantical rule is a universally quantified affirmation accepted as true and viewed in logical supposition in the metalinguistic perspective, such that the meaning of the predicate term displays some component part or parts of the meaning of the subject term.

58. Section 3.22 Introduction Componential semantics: –The meanings of descriptive terms are complex and have component parts. Componential semantics has been overlooked in philosophy. Componential semantics has been recognized in linguistics.

59. Section 3.22 Introduction Semantical change in science: –When there is a transition from an old theory to a new theory having the same test design, for advocates of the old theory there occurs a semantical change in the two theories’ shared descriptive terms due to the replacement of the meaning parts from the old theory with meaning parts from the new theory. But the meaning parts contributed by the test-design language remain unaffected.

60. Section 3.24 Introduction Semantic Values: –Semantic values are the elementary component parts distributed among the meaning complexes associated with the descriptive terms of a language at a point in time.

61. Section 3.25 Introduction Equivocal and univocal terms: –A descriptive term’s use is univocal, if no universally quantified negative statement accepted as true can relate any of the predicates in any of the several universal affirmations functioning as semantical rules for the same subject term. Otherwise the descriptive term’s use is equivocal.

62. Section 3.26 Introduction Supposition: –S upposition reveals ambiguity in the description of ontology by univocal terms due to different roles the terms have in statements.

63. Section 3.26 Introduction Real supposition: –The subject-term role in a sentence in object language has personal supposition, because it references individual entities. –The predicate-term role in a sentence in object language has simple supposition, because it describes attributes but does not reference entities. Thus predicates are not quantified.

64. Section 3.26 Introduction Logical supposition: –In logical supposition the meaning of a term is referenced specifically as a meaning. Semantical rules are in the metalinguistic perspective and in logical supposition.

65. Section 3.27 Introduction Metaphor: –A metaphor is a predication to a subject term that is intended to include only selected parts of the meaning complex conventionally associated with the predicate term, so the metaphorical predication is a true statement, while excluding the remaining parts in the predicate’s meaning complex that would make the metaphorical predication a false statement.

66. Section 3.28 Introduction Clear and vague meanings: –Meanings are more or less clear and vague, such that the greater the clarity, the less the vagueness.

67. Section 3.28 Introduction Clarity enhancement: –Clarity is increased by adding one or several universal statements believed to be true to the list of semantical rules for the given univocal subject term. The universal statements may be either affirmative or negative.

68. Section 3.28 Introduction Coherence enhancement: –Clarity is also increased by adding universally quantified affirmations believed to be true, which relate some of the predicates occurring in the various semantical rules for the given subject term. The coherence enhancement is due to the resulting deductive system, which adds structure to the meaning parts.

69. Section 3.29 Introduction Semantics of Mathematics: –The semantics for a descriptive mathematical variable is determined by its context consisting of universally quantified statements including mathematical expressions, which are believed to be true.

70. Section 3.30 Introduction Semantical state description: –A synchronic display of the semantical composition of the various meanings of the partially equivocal descriptive terms in the alternative theories functioning as semantical rules and addressing a single problem defined by a shared test design. Each theory’s advocates believe that empirical testing will validate their theory preference.

71. Section 3.31 Introduction Diachronic comparative-statics: –Consists of two state descriptions representing two chronologically successive language states sharing a common subset of descriptive terms in a shared test design. –The comparison is made to exhibit semantical change especially between discovery-system input and output state descriptions.

72. Section 3.32 Introduction Diachronic dynamic analysis: –Consists of two state descriptions representing: (1) two chronologically successive language states sharing a common subset of descriptive terms including those in a shared test design, and (2) a process of change between the state descriptions. –A discovery-system design describes a process of linguistic change from an initial state description to a later one.

73. Section 3.33 Introduction Computational philosophy of science: –The development of computerized discovery systems that proceduralize explicitly the past achievements of successful scientists, in order to apply the successful mechanized procedures to the current state description of a science and thereby develop a new state description containing one or several new and superior theories.

74. Section 3.34 Introduction Interpretations of discovery systems: –Cognitive psychology approach. a.k.a. “artificial intelligence”. –Linguistic analysis approach.

75. Section 3.34 Introduction Cognitive psychology approach: –Computer systems are hypotheses about intuitive human problem-solving processes. –Difficulties: In practice computer procedures have not been compared with human cognitive processes to test psychological hypotheses. Successful systems are known to operate differently from intuitive thinking by historical discoverers.

76. Section 3.34 Introduction Linguistic analysis approach: –Computer systems are generative grammars. No psychological claims are made about intuitive thinking processes. –State descriptions represent the ideas in a language community,i.e., a scientific profession. Like the profession, the system produces and tests a diversity of new theories.

77. Section 3.34 Introduction Linguistic systems analysis: –Computer discovery systems are generative grammars that generate and test theories. The system inputs and outputs are both object- language state descriptions. The instructional code of the computer system is in the metalinguistic perspective, and exhibits the diachronic dynamic procedures for theory development.

78. Section 3.35 Introduction Ontological dimension: –Ontology consists in the semantically revealed aspects of mind-independent reality. Semantics is description of reality Ontology is reality as described.

79. Section 3.36 Introduction Metaphysical realism: –Metaphysical realism is the thesis that there exists mind-independent reality that is accessible to and accessed by human cognition. –When metaphysical realism is joined with relativized semantics, the result is ontological relativity.

80. Section 3.36 Introduction Scientific realism: –Scientific realism is the thesis that the most critically tested and currently nonfalsified theory, which is thus accepted as a scientific law, offers the most empirically adequate and most realistic description of reality at the current time. A scientific law is a tested and nonfalsified universally quantified statement that prior to its empirical testing was a proposed theory.

81. Section 3.37 Introduction Ontological relativity: –Ontological relativity in science is the thesis that the semantics of a scientific law and its constituent descriptive terms describe reality.

82. Section 3.37 Introduction Scientific laws: –A scientific law is a tested and nonfalsified universally quantified statement that prior to its decisive testing had been a theory.

83. Section 3.38 Introduction More or less realistic ontology: –There is no semantically interpreted syntax that does not reveal some more or less realistic ontology. –There is no semantically interpreted syntax that is utterly devoid of ontological significance.

84. Section 3.41 Introduction Pragmatic dimension: –Pragmatics is the uses or functions of language consisting of semantically interpreted syntax and described ontology.

85. Section 3.43 Introduction Pragmatic definition of theory: –Scientific theories are universally quantified statements including mathematical expressions (or “models”) that are proposed for empirical testing. –Testing is the pragmatics of theories. Thus theory is a special use of language rather than a special type of language.

86. Section 3.43 Introduction Theories are relatively hypothetical: –Theories are hypothetical because scientists believe that theory statements are more likely to be productively revised than the test-design statements, if a falsifying test outcome shows that revision is needed.

87. Section 3.43 Introduction Pragmatic vs archival meanings for “theory”: –On the pragmatic definition “theory” identifies the temporary status of language for testing. E.g., Einstein’s tested theory no longer has theory status. It is the currently tested and nonfalsified law of gravitation. –On the archival definition “theory” is a permanent status of the language as in an historical archive. E.g., Einstein’s tested theory like Newton’s is still often called a “theory” of gravitation.

88. Section 3.44 Introduction Pragmatic definition of test-designs: –Pragmatically theory is universally quantified language that is proposed for testing, and test-design language is universally quantified language that is presumed for testing.

89. Section 3.45 Introduction Pragmatic definition of observation language: –Observation sentences are test-design and test-outcome sentences given particular logical quantification for describing an individual test execution including the reporting of a test outcome.

90. Section 3.46 Introduction Observation and test execution: –Statements predicting test outcomes have semantics defined by universally quantified theory statements with their logical quantification made particular for the individual test execution. –Statements reporting observed test outcomes have semantics defined by universally quantified test- design statements with their logical quantification made particular for the individual test execution.

91. Section 3.47 Introduction Scientific profession: –For computational philosophy of science a scientific profession is the researchers who at a given time are attempting to solve the same scientific problem as defined by a test design.

92. Section 3.48 Introduction Theories are individuated semantically. –Theory language is defined pragmatically, but theories are individuated semantically.

93. Section 3.48 Introduction Theory individuation principles: –Different theory expressions are different theories either because: They address different subjects, or Each makes contrary claims about the same subject.

94. Chapter IV Functional Topics in Basic-Science

95. Section 4.01 Introduction The institutionalized aim of science: –The institutionalized aim of science is the cultural value system that regulates scientists’ performance of basic research. –The value system is summarily expressible as a statement of the aim of science.

96. Section 4.02 Introduction Positivist aim of science: –Early positivists aimed to create explanations having objective basis in observations and in empirical generalizations summarizing individual observations. –Later neopositivists aimed to justify theories for explanations by logically relating the theoretical terms in the theories to observation terms that they believed are a foundational reduction base.

97. Section 4.03 Introduction Romantic aim of science: –The aim of the social sciences is to develop explanations in terms of subjective social- psychological motives, in order to explain observed social interaction in terms of purposeful human action in society. Sciences of culture thus differ fundamentally in their aim from the sciences of nature.

98. Section 4.06 Introduction Pragmatist aim of science: –The successful outcome of basic-science research is an explanation, which is achieved by developing theories that satisfy the most critically empirical tests that can be applied to the theories at the current time, and which are thereby regarded as scientific laws that function as premises in deductive explanations of particular events.

99. Section 4.07 Introduction Change of the institution of science: –Institutional change is the evolution of scientific practices involving revision of the aim of science including its criteria for criticism, its discovery practices, or its concept of explanation. –Institutional changes are historically unique developments recognized retrospectively after they have become conventionalized in science.

100. Section 4.07 Introduction Change within the institution of science: –Change within the institution of science is change made under the regulation of the institutionalized aim of science. –It consists of new theories, new test designs, new laws or new explanations.

101. Section 4.10 Introduction Scientific discovery: –The topic of scientific discovery pertains to the creation of new theories. Contemporary pragmatism is consistent with use of computerized discovery systems.

102. Section 4.11 Introduction Computerized discovery systems: –A computerized discovery system produces a transition from one language state description to another by generating and empirically testing new theories.

103. Section 4.12 Introduction Types of theory development: –Theory extension –Theory elaboration –Theory revision

104. Section 4.12 Introduction Theory extension: –The use of a currently tested and nonfalsified explanation to address a new scientific problem. E.g. Thagard’s system PI that uses analogy with existing explanations applied to a new problem.

105. Section 4.12 Introduction Theory elaboration: –The correction of a currently falsified theory to create a new theory by the addition of new factors or variables. E.g. Langley’s system BACON that is a sequential application of theory elaboration using Simon’s “heuristic search” algorithm.

106. Section 4.12 Introduction Theory revision: –The reorganization of currently existing information to create a new theory. E.g. Hickey’s METAMODEL system that is a “generate-and-test” design.

107. Section 4.14 Introduction Scientific criticism: –Criticism pertains to the criteria for the acceptance or rejection of theories. –The only criterion for scientific criticism that is acknowledged by the contemporary pragmatist is the empirical criterion.

108. Section 4.15 Introduction Hypothetical-conditional statement form: –The form is: If “A”, then “C”. “A” is the antecedent discourse. “C” is the consequent discourse. The conditional form asserts a dependency of “C” upon “A”, a causal relation. The form does not assert a truth-functional relation, as does the Russellian “material implication” symbol . The form does not assert merely a Humean constant conjunction.

109. Section 4.15 Introduction Rules for hypothetical-conditional logic: –Modus tollens: One can deny the consequent clause, and then either deny the antecedent clause or deny the hypothetical-conditional statement. Modus tollens argument is used for falsification in empirical testing. –Modus ponens: If the hypothetical-conditional statement is true, one can affirm the antecedent clause, and then validly affirm the consequent clause. Modus ponens argument is used in explanation.

110. Section 4.15 Introduction Empirical test defined: –An empirical test is a decision procedure consisting of a modus tollens deduction from a set of one or several universally quantified theory statements expressible jointly in a nontruth-functional hypothetical-conditional schema proposed for testing together with an antecedent particularly quantified description of the initial test conditions. These statements jointly conclude to a consequent particularly quantified description of a predicted test outcome event.

111. Section 4.15 Introduction Modus tollens argument in criticism: –Test execution: Theory predicting C - “If A, then C.” Initial conditions A -“A” is true. Test outcome C -“C” is not true. –Therefore the theory “If A, then C” is falsified.

112. Section 4.15 Introduction Nontruth-functional conditional logic operative in scientific criticism: Truth-Functional Nontruth-Functional Truth Table Truth Table ABA  BABIf A, then B. TT TTT Not Falsified TF F TF Falsified FT TFT Invalid Test FF TFF Invalid Test

113. Section 4.17 Introduction Ordinary semantics of empirical testing: –A nonfalsifying test outcome leaves the semantics unchanged for the advocates of the tested theory. –But a falsifying test outcome changes semantics: The parts of the meanings contributed by the falsified theory statements are excluded from the semantics of the terms common to the theory and the test-design. The test-design statements continue to contribute their meaning parts to the meaning complexes of the terms common to the test design and theory terms.

114. Section 4.18 Introduction Hypothetical Status of Theory: –Theory language is relatively more hypothetical than test-design language, because the interested scientists agree that in the event of a falsifying test outcome, revision of the theory will likely be more productive than revision of the test-design language.

115. Section 4.18 Introduction Semantics of test-design revision: –If a scientist rejects a test design in response to a falsifying test outcome, he has made the theory’s semantics define the subject of the test and the problem under investigation. This is a role reversal in the pragmatics of theory language and test-design language.

116. Section 4.18 Introduction Decidability of an empirical test: –Empirical tests are conclusive decision procedures only for those scientists who: Agree upon which language is proposed theory and which language is presumed test design, Accept the test-design, and Accept the test execution outcomes with the accepted test design.

117. Section 4.19 Introduction Empirical underdetermination: –Vagueness and measurement error are manifestations of empirical underdetermination. –Empirical underdetermination can be reduced indefinitely but never completely eliminated. –Empirical tests are conclusive only when empirical underdetermination is small relative to the effect predicted in an test.

118. Section 4.20 Introduction Scientific pluralism: –Scientific pluralism is recognition of the coexistence of empirically adequate alternative explanations due to undecidability permitted by test-design language that is too underdetermined empirically.

119. Section 4.21 Introduction Scientific truth: –Truth and falsehood are properties of statements, and admit to more or less. Tested and nonfalsified statements are more empirically adequate, have more truth and have more realistic ontologies than falsified ones. Falsified statements have recognized error, and may simply be rejected unless they are still useful for their lesser realism and lesser truth.

120. Section 4.24 Introduction Empirical constraint: –The empirical constraint is the institutionalized value that regulates theory acceptance or rejection. –It is the unique constraint that is respected as the condition for scientific progress. –All other constraints must be overcome for science to progress.

121. Section 4.22 Introduction Nonempirical criteria: –Philosophers and scientists have proposed nonempirical criteria for choosing among multiple alternative empirically adequate explanations permitted by empirical underdetermination. But no nonempirical criterion enables predicting reliably which alternative nonfalsified explanation will survive new empirical testing, when the degree of underdetermination is reduced by improved test design.

122. Section 4.23 Introduction “Best explanation” nonempirical criteria: –Thagard’s simulations of past episodes in the history of science with his system ECHO indicate important nonempirical criteria for “best explanation” are: Firstly, breadth of explanation, followed by Secondly, simplicity of explanation, and then Thirdly, analogy with previously accepted explanations.

123. Section 4.24 Introduction Nonempirical linguistic constraints: –Two nonempirical constraints inherent in language that must be overcome are: The “cognition constraint” and The “communication constraint”.

124. Section 4.26 Introduction Principle of linguistic constraints to theory change: –Given a conventionalized meaning for a descriptive term, certain beliefs defining the meaning of the term are reinforced by habitual linguistic fluency with the result that the meaning’s conventionality impedes change in those beliefs.

125. Section 4.25 Introduction The cognition constraint: –The cognition constraint is the impediment to a scientist’s ability to construct new theories. In the intuitive discovery process the scientist must cognitively restructure the meaning complexes associated with the descriptive terms in the currently accepted theory, if there is one. Computerized discovery systems have no cognition constraints.

126. Section 4.26 Introduction The communication constraint: –The communication constraint is the impediment to understanding a new theory relative to those currently conventional. The scientist must learn the new theory to restructure the composite meaning complexes associated with the descriptive terms common both to the old theory and a new theory to which he is exposed. Scientists will experience the communication constraint in attempting to learn the new theories in a computer outputted state description.

127. Section 4.27 Introduction Hypothetico-deductive explanation: –The explanation is a modus ponens type of argument. –Tested and nonfalsified laws are accepted as true by virtue of their demonstrated empirical adequacy. –Then the laws and logic have the form: Tested & nonfalsified law - “If A, then C.” is true. Realized initial conditions - “A” is true. Explained outcome - Thus “C” is true.

128. Section 4.27 Introduction Scientific explanation: –A scientific explanation is a discourse consisting of a modus ponens deduction with a set of one or several related universally quantified law statements expressible jointly in a nontruth-functional hypothetical-conditional schema together with particularly quantified antecedent description of initial conditions, which together conclude to particularly quantified consequent description of the occurrence of the explained event.

129. Section 4.27 Introduction The explanation: –The tested and nonfalsified laws together with statements of initial conditions are called the explanans. –The statement of explained outcome is called the explanandum.