Preface
• These slides are based on BOOK I at:
– www.philsci.com
and on the e-books:
– Philosophy of Science: An Introduction
and
– Twentieth-Century Philosophy of Science:
A History.
• 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.
Philosophy
of
Science
An Introduction
The ebook
Twentieth
Century
Philosophy
of
Science
the e-book and
BOOK I in
the web site
www.philsci.com
(A free download)
CONTENTS
Chapter I
Overview
Chapter II
Three Modern Philosophies
Chapter III
Philosophy of Language
Chapter IV
Philosophy of Science Topics
Chapter I
Overview
Introduction
• The aim of 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, and then
• to advance contemporary science by application
of the principles.
Section 1.01
Introduction
• Computational philosophy of science:
– Computational philosophy of science is the
design, development and application of
computerized discovery systems that
mechanize and thus proceduralize productive
research practices in the sciences.
• Application of the computer systems gives the
computational philosopher of science a practical,
participatory and consequential role in
contemporary basic scientific research.
Section 1.02
Introduction
• Modern philosophies:
– 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.
Section 1.06
Introduction
• Functional topics:
– Aim of Science.
• The institutionalized aim of basic research.
– Discovery.
• Development of new theories.
– Criticism.
• Criteria for evaluating theories.
– Explanation.
• Scientific explanation - the final result.
Section 1.05
Introduction
• Relation of the three philosophies
and the four topics:
Aim of
Science
Discovery Criticism Explanation
Romanticism
Positivism
Pragmatism
Section 1.05 - 1.06
Introduction
• Perspectives on language:
– Object Language
• Language describing nonlinguistic reality
– Metalanguage
• Language describing language
Section 1.03
Introduction
• Meanings of common metalinguistic
terms differ among the philosophies
Aim of
Science Discovery
Metalinguistic
terms
"theory"
"law"
Romanticism
Positivism
Pragmatism
Section 1.05 - 1.06
Criticism
Explanation
"observation"
"scientific
explanation"
Introduction
• Dimensions of language:
– Syntax.
• The structure of language.
– Semantics.
• The meanings associated with syntax.
– Ontology.
• The reality described by semantics.
– Pragmatics.
• The use of language in science.
Section 1.04
Introduction
• Dimensions are inclusively related:
Pragmatics
Semamtics
Ontology
Syntax
Section 1.04
Chapter II
Three Modern
Philosophies
Introduction
• Romanticism - Aim of Science:
– The aim of the social and cultural sciences is
“interpretative understanding” of “human
action”, by which is meant description of the
culturally shared subjective ideas and motives
that influence the social interactions of social
members.
Section 2.01
Introduction
• Romanticism - Discovery:
– “Theory” is language describing
subjective mental states including notably
culturally shared ideas and motivations.
• The development of theory in social science
may involve the social scientist’s introspective
reflection on his own motivations, to
understand by imputation the subjective
mental states of the social members.
Section 2.01
Introduction
• Romanticism - Criticism:
– The criterion for criticism is “interpretative
understanding”, because the subjective ideas
and motives described in social theory are
deemed to be the causal factors of observed
social behavior.
• Social theory must “make sense” in the particular
investigator’s own subjective personal or
vicarious experience.
Section 2.01
Introduction
• Romanticism - Explanation:
– Only theory describing subjective
motives can “explain” conscious
human action.
• Motives are the causal factors identified
in “theoretical” explanations.
Section 2.01
Introduction
• Positivism - Aim of Science:
– To produce explanations having
objectivity grounded in observation
language.
Section 2.02
Introduction
• Positivism - Discovery:
– Empirical laws are created by inductive
generalization based on repeated observations.
– “Theories” referencing unobservable entities
or phenomena are developed by the scientist’s
creative imagination by processes, which are
unexplained by positivists.
Section 2.02
Introduction
• Positivism - Criticism:
– The criterion for criticism is publicly
accessible observation expressed in
observation language.
– Theories are indirectly and tentatively
warranted by empirical laws, when the
laws can be logically derived from the
theories.
Section 2.02
Introduction
• Positivism - Explanation:
– According to the “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 “deductivenomological model” of explanation.
Section 2.02
Introduction
• Pragmatism - Three fundamental theses
formulated in the 1920’s by the Nobel laureate
physicist Werner Heisenberg that anticipated
the contemporary pragmatism:
– Thesis I: Relativized semantics.
– Thesis II: Empirical underdetermination.
– Thesis III: Ontological relativity.
Section 2.03
Introduction
• Thesis I: Relativized semantics.
– In 1925 Einstein told Heisenberg that
“theory decides what the physicist can
observe”.
• Thus contrary to positivists observational
description is not independent of theory.
Section 2.03
Introduction
• Thesis II: Empirical underdetermination.
– A plurality of alternative but empirically
adequate theories can be consistent with the
same observational description.
– Examples of empirical underdetermination:
• Vagueness, which can be reduced but never
completely eliminated.
• Measurement has error, which in nontrivial cases can
be reduced but never completely eliminated.
Section 2.03
Introduction
• Thesis III: Ontological relativity.
– The semantics of language accepted as true
describes ontology.
• Einstein construed his relativity theory as a
realistic description of physical reality.
• Heisenberg imitated Einstein by construing his
quantum theory as a realistic description of
physical reality.
Section 2.03
Introduction
• Pragmatism - Aim of Science:
– The aim of basic science is
explanation.
• Explanations contain laws from which
descriptions of concrete events are
logically derived.
• Laws are former theories that have been
tested and not falsified.
Section 2.03
Introduction
• Pragmatism - Discovery:
– “Theory” and “observation” language are
defined pragmatically instead of semantically.
– The pragmatics of theory is empirical testing.
• Theories are individuated semantically.
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.
Section 2.03
Introduction
• Pragmatism - Criticism:
– Empirical testing is the only valid decision
criterion for theory evaluation.
• Theories can be logically schematized as
nontruth-functional hypothetical-conditional
statements.
• The modus tollens deductive logic is used for
empirical testing.
Section 2.03
Introduction
• Pragmatism - Explanation:
– Scientific laws can be logically schematized as
nontruth-functional hypothetical-conditional
statements.
• The modus ponens deductive logic is used for
explanation.
Section 2.03
Chapter III
Philosophy of
Language
Introduction
• Dimensions of Language:
–
–
–
–
Syntax - forms of language.
Semantics - meanings of language.
Ontology - reality as described by language.
Pragmatics - uses of language.
Section 3.03
Introduction
• Syntactical Dimension:
– Syntax is the system of symbols in
linguistic expressions considered
in abstraction from the meanings
associated with the symbols.
Section 3.04
Introduction
• Syntactical formation rules:
– Expressions in metalanguage that
regulate construction of grammatical
sentences out of more elementary
symbols.
• E.g., combining words into sentences.
Section 3.05
Introduction
• Generative grammar discovery system:
– A generative grammar is a system that applies
formation rules to more elementary syntactical
symbols, to produce grammatical sentences or
well-formed mathematical expressions.
• A computerized discovery system is a generative
grammar that constructs and empirically tests scientific
theories as its output.
Section 3.05
Introduction
• Semantical Dimension:
– Semantics is the meanings
associated with syntactical
symbols.
Section 3.08
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 to be true.
Section 3.10
Introduction
• Romantic semantics:
– Social-theory semantics that describes
the subjective meanings and motives
of the social members investigated by
the social scientist.
Section 3.11
Introduction
• Positivist semantics:
– Observation semantics as causally
determined by nature and acquired
ostensively by perception.
Section 3.12
Introduction
• Positivist semantical theses:
– Meaning invariance.
– Analytic-synthetic dichotomy.
– Observation-theory dichotomy.
Section 3.12
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.
Section 3.13
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.”
Section 3.14
Introduction
• Observation-theory dichotomy thesis:
– Observation terms reference or describe
observable entities and phenomena.
• E.g., “raven” and “black”.
– Theoretical terms do not reference or describe
observable entities or phenomena.
• E.g., “electron” and “virus”.
Section 3.15
Introduction
• Pragmatists reject meaning invariance.
– Pragmatists say that semantics of every descriptive
term is determined by the term’s linguistic context
consisting of universally quantified statements
believed to be true.
• Thus a change in any of those beliefs changes some
parts of the constituent terms’ meanings.
Section 3.19
Introduction
• Pragmatists reject the
analytic-synthetic dichotomy.
– All universally quantified affirmations
believed to be true are both analytic
and synthetic.
• They are called “analytical hypotheses”.
Section 3.20
Introduction
• Pragmatists reject the
observation-theory dichotomy.
– Pragmatists reject natural semantics for
identifying language used for
observational reporting.
• Thus there is no separate class of theoretical
terms.
Section 3.18
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 one or several
component parts of the meaning complex
associated with the subject term.
Section 3.21
Introduction
• Componential semantics:
– The meanings of descriptive terms are
complex and have component parts.
• Componential semantics is recognized in
linguistics.
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, there
occurs a semantical change in the theories’
shared descriptive terms due to the replacement
of the meaning parts from the old theory with
meaning parts from the new theory.
Section 3.22
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.
Section 3.25
Introduction
• Supposition:
– Supposition is ambiguity in the
description of ontology by univocal
terms due to different roles the
terms have in statements.
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.
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.
Section 3.26
Introduction
• Clear and vague meanings:
– Terms are either univocal or equivocal.
– Meanings are more or less clear and
vague, such that the greater the clarity,
the less the vagueness.
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 statement may be either
affirmative or negative.
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.
Section 3.28
Introduction
• Analytical views:
– Synchronic view exhibits a single point in
time - like a photograph. It is static.
– Diachronic view exhibits change over a
time interval.
• Comparative-static view exhibits two points in
time - like “before” and “after” photos.
• Dynamic view exhibits a transitional process
of change through time - like a motion picture.
Section 3.01
Introduction
• Semantical state description:
– A synchronic display of the semantical
composition of the meanings of the
descriptive terms contained in a set of
alternative theories addressing the same
problem defined by a common test design.
• Each theory’s advocates believes that empirical
testing will make his/her theory definitive.
Section 3.30
Introduction
• Diachronic comparative-statics:
– Consists of two state descriptions representing
two chronologically successive language states
sharing a common subset of descriptive terms
including those in a shared test design.
– The comparison is made to exhibit semantical
change between discovery system input and
output state descriptions.
Section 3.31
Introduction
• Diachronic dynamic analysis:
– Comparison of two state descriptions representing
two chronologically successive language states
sharing a common subset of descriptive terms
including those in a shared test design, and a
process of change between the state descriptions.
– A discovery system design describes a process of
linguistic change over a period of time from one
language state to a later one.
Section 3.32
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 mechanized procedures to the current
state description of a science, in order to develop
a new state description containing one or several
new and superior theories.
Section 3.33
Introduction
• Interpretations of discovery systems:
– Cognitive psychology approach.
• a.k.a. “artificial intelligence”.
– Linguistic analysis approach.
Section 3.34
Introduction
• Cognitive psychology approach:
– Computer systems are hypotheses about
human problem-solving processes.
– Difficulties:
• In practice computer procedures have not been
compared with human cognitive processes to
test psychological hypotheses to corroborate
psychological claims.
• Systems are known to operate differently from
intuitive thinking by discoverers.
Section 3.34
Introduction
• Linguistic analysis approach:
– Computer systems are language processing
systems, viewed instrumentally.
• 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 a
diversity of theories.
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.
Section 3.34
Introduction
• Ontological dimension:
– Ontology is the aspects of reality
described by semantically
interpreted syntax.
Section 3.35
Introduction
• Metaphysical realism:
– The thesis that there exists mind-independent
reality accessible to human cognition.
Section 3.36
Introduction
• Scientific realism:
– The thesis that the most critically tested and
currently nonfalsified theory offers the most
empirically adequate description of reality
at the current time.
Section 3.36
Introduction
• Ontological relativity:
– The thesis that the semantics of a scientific
law and its constituent descriptive terms
describe reality.
• A scientific law is a tested and nonfalsified
universally quantified statement that prior to its
empirical testing was a proposed theory.
Section 3.37
Introduction
• Pragmatic dimension:
– Pragmatics is the use or functions of
semantically interpreted syntax and
described ontology.
Section 3.41
Introduction
• Pragmatic definition of theory:
– Empirical testing is the pragmatics of theories.
– Scientific theories are universally quantified
statements that are proposed for testing.
• Theories are proposed for testing because they are
deemed more hypothetical.
• They are deemed more hypothetical because, if
falsified they are presumed more likely to need
revision than other beliefs including notably the
test design.
Section 3.43
Introduction
• Pragmatic vs archival meanings for
“theory”:
– On the pragmatic definition “theory” identifies the
temporary status of language awaiting testing.
• E.g., Einstein’s tested theory no longer has theory status.
It is the current law of gravitation.
– On the archival definition “theory” is a permanent
status as in a historical archive.
• E.g., Einstein’s tested theory like Newton’s is still a
theory of gravitation.
Section 3.43
Introduction
• Pragmatic definition of test-designs:
– Theory language is universally quantified
statements or equations that are proposed for
testing.
– Test-design language is universally quantified
statements or equations that are presumed for
testing.
Section 3.44
Introduction
• Pragmatic definition of observation
language:
– Observation sentences are test-design
sentences and test-outcome sentences with
particular logical quantification for describing
an individual test execution including
reporting the test outcome.
Section 3.45
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 testdesign statements with their logical quantification
made particular for the individual test execution.
Section 3.45
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.
Section 3.47
Introduction
• Theories are individuated semantically.
– Theory language is defined pragmatically.
– Theories are individuated semantically.
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.
Section 3.48
Chapter IV
Philosophy of
Science Topics
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.
Section 4.01
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.
Section 4.02
Introduction
• Romantic aim of science:
– The aim of the social sciences is to develop
explanations in terms of subjective socialpsychological 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.
Section 4.03
Introduction
• Pragmatist aim of science:
– The contemporary pragmatist statement
of the aim of basic science:
• To create explanations by the development
and empirical testing of theories, which
become laws, when the tested theories are
not falsified.
Section 4.06
Introduction
• Change of the institution of science:
– Institutional change is the evolution of
scientific practices involving revision of the
aim of science or its criteria for criticism.
Section 4.07
Introduction
• Change in the institution of science:
– Change within the institution of science is
change made under the regulation of the
institutionalized aim of science.
Section 4.07
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.
Section 4.10
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.
Section 4.11
Introduction
• Types of theory development:
– Theory extension
– Theory elaboration
– Theory revision
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 for a new
problem.
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.
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.
Section 4.12
Introduction
• Scientific criticism:
– Criticism pertains to the criteria for the
acceptance or rejection of theories.
– The only criterion acknowledged by
the contemporary pragmatists is the
empirical criterion.
Section 4.14
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.
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 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.
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.
Section 4.15
Introduction
• Nontruth-functional conditional logic for
scientific criticism:
Truth-Functional
Truth Table
A
B
AB
T
T
T
T
F
F
F
T
T
F
F
T
Nontruth-Functional
Truth Table
A
B
If A, then B.
T
T
Not Falsified
T
F
Falsified
F
T
Invalid Test
F
F
Invalid Test
Section 4.15
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.
Section 4.17
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 testdesign language and theory language.
Section 4.18
Introduction
• Conclusiveness 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.
Section 4.18
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.
Section 4.19
Introduction
• Scientific pluralism:
– Scientific pluralism is the recognition of the
coexistence of alternative yet empirically
adequate explanations for the same problem
due to undecidability among the alternative
laws, which in turn is due to excessive
empirical underdetermination.
Section 4.20
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.
Section 4.21
Introduction
• Empirical constraint:
– The empirical constraint is the
institutionalized value that regulates theory
acceptance or rejection.
– It is the constraint that is respected as the
condition for scientific progress.
– All other constraints must be overcome for
science to progress.
Section 4.24
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.
Section 4.22
Introduction
• “Best explanation” nonempirical criteria:
– Thagard’s simulations of past episodes in the history of
science with his system ECHO indicate that the most
important nonempirical criteria for “best explanation”.
– They are:
• Firstly, breadth of explanation, followed by
• Secondly, simplicity of explanation, and then
• Thirdly, analogy with previously accepted explanations.
Section 4.23
Introduction
• Nonempirical linguistic constraints:
– Two nonempirical constraints inherent in
language that must be overcome are:
• The “cognition constraint” and
• The “communication constraint”.
Section 4.24
Introduction
• Principle of linguistic constraints:
– Meanings of terms are determined by beliefs.
– Conversely given the established meaning of a
descriptive term, certain beliefs are determined
and are reinforced by habitual linguistic fluency
with the result that the conventionality of the
term’s meaning impedes a change in those
beliefs.
Section 4.24
Introduction
• The cognition constraint:
– The cognition constraint is the impediment to
a scientist’s ability to construct new theories.
• In the discovery process the scientist must
cognitively restructure the meaning complexes
associated with the descriptive terms in the
currently accepted theory, if there is one.
Section 4.25
Introduction
• The communication constraint:
– The communication constraint is the impediment
to understanding a new theory relative to those
currently conventional.
• The scientist must cognitively learn the new theory well
enough to restructure the composite meaning complexes
associated with the descriptive terms common both to
the old theory he already knows and to the new theory
to which he is exposed.
Section 4.26
Introduction
• Scientific explanation:
– A scientific explanation is a modus ponens
deduction with one or several universally quantified
explanatory law statements expressible in the
nontruth-functional hypothetical-conditional schema
together with particularly quantified antecedent
language describing initial conditions, which jointly
conclude to particularly quantified consequent
language describing the explained event.
Section 4.27
Introduction
• Hypothetico-deductive explanation:
– The explanation is a modus ponens type of argument.
– Tested and nonfalsified laws have been accepted as true
by virtue of 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.
Section 4.27
Introduction
• The explanation:
– The tested and nonfalsified laws together with
statements of initial conditions are called the
explicans or explanans.
– The statement of explained outcome is called the
explicandum or explanandum.
Section 4.27