Transcript Document

Scientific Progress and Its
Problems
Verification, Falsification or
What?
Lecture 3
1
Introduction
The aim of the lecture is
 To present the major conceptions of
scientific growth
 To discuss their respective strong and
weak points.
Lecture 3
2
Main Topics


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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



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)


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)

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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
Laws and
theories
Deduction
Induction
Facts acquired
through
observation
Predictions and
explanations
Lecture 3
7
Popper’s Falsificationism (1)

Not verification, but falsification


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)


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)


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)


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)

A theory can never be said to be true


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)

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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)

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)

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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)

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
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Kuhn’s Structural Criterion of
Science (5)

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)

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
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Thomas Kuhn’s Structural
Criterion of Science (7)
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Normal science
Crisis
Revolutionary science
‘Gestalt’ switch
New period of normal science

New paradigm is incommensurable with
previous one
Lecture 3
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Thomas Kuhn’s Structural
Criterion of Science (8)

A paradigm will never be replaced
unless a ‘less problematic or better’
one comes around
Lecture 3
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Thomas Kuhn’s Structural
Criterion of Science (9)

Within this general process of
development of science Kuhn
stresses:


the importance of the scientific
community
the role of extra-scientific elements
Lecture 3
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Thomas Kuhn’s Structural
Criterion of Science (9)


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
 A theory is falsified by an observational
statement that conflicts with it
Lecture 3
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Lakatos, Sophisticated Falsificationism,
and Research Programmes (2)
Sophisticated falsificationism

A theory T1 is falsified if another theory T2
has been proposed with the following
characteristics:

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T2 has excess empirical content over T1: that is, if
it predicts novel facts
T2 explains the empirical content of T1
Some of the excess content of T2 is corroborated
Lecture 3
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Lakatos, Sophisticated Falsificationism,
and Research Programmes (3)
Research programmes
 Theories are part of broader structures,
which Lakatos calls “research
programmes”
 Within such a programme theories
develop in a dynamic way
Lecture 3
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Lakatos, Sophisticated Falsificationism,
and Research Programmes (4)

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
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Lakatos, Sophisticated Falsificationism,
and Research Programmes (5)

Such a sequence of interrelated theories
is what Lakatos calls a scientific
research programme
Lecture 3
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Lakatos, Sophisticated Falsificationism,
and Research Programmes (6)

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
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Lakatos, Sophisticated Falsificationism,
and Research Programmes (7)

Whenever observations do not fit
smoothly into this framework and
objections are raised the rational
response is


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)

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
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Lakatos, Sophisticated Falsificationism,
and Research Programmes (9)
When is a research programme falsified?
 A research programme R1 is falsified
when there is an alternative research
programme R2 that
1.
2.
can explain and predict as much as
research programme R1 does
predicts novel facts, some of which are
corroborated
Lecture 3
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Feyerabend: the Abandonment for the
Search of ‘The’ Method

Feyerabend’s key points are:

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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)
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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
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Laudan’s Research Traditions
(2)

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 the
theories in that domain
(epistemology and methodology).
Lecture 3
34
Laudan’s Research Traditions
(3)

Contrary to Lakatos these general
assumptions (hard core assumptions if
you wish) may change
Lecture 3
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Laudan’s Research Traditions (4):
Empirical and Conceptual Problems

For Laudan science is


not only about empirical problems
but also about conceptual problems
Lecture 3
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Laudan’s Research Traditions (5):
Nature of Empirical Problems
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Empirical problems are problems
about the world
Empirical problems are theory-laden
as they are generated within a
certain theoretical structure
Lecture 3
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Laudan’s Research Traditions (6):
Nature of Empirical Problems

He distinguishes three kind of
empirical problems:



solved problems
unsolved problems
anomalous problems
Lecture 3
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Laudan’s Research Traditions (7):
Nature of Conceptual Problems

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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
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Laudan’s Research Traditions (8):
Sources of Conceptual Problems
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Intra-scientific difficulties
Normative difficulties
Worldview (ontological) difficulties
Lecture 3
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Laudan’s Research Traditions (9):
Core Assumptions


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

The first and essential test for any
theory is whether

it provides acceptable answers to
interesting questions:

whether, in other words, it provides satisfactory
solutions to important problems
Lecture 3
42
Larry Laudan’s Research Traditions
(11): Evaluation of Theories

In appraising the merits of theories, it is more
important to ask



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
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Larry Laudan’s Research Traditions (11):
Evaluation of Theories

The overall effectiveness of a theory is
determined by


assessing the number and importance of the
empirical problems, which the theory solves,
and
deducting thereof the number and
importance of the anomalies and conceptual
problems, which the theory generates,
determine the overall effectiveness of a
theory
Lecture 3
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How to Judge the Value of a Scientific
Theory or Model? A Few Rules of Thumb
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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
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How to Judge the Value of a Scientific
Theory or Model? A Few Rules of Thumb

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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
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How to Judge the Value of a Scientific
Theory or Model? A Few Rules of Thumb

To which extent does it lead to the
construction of a new and better
model?
Lecture 3
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