- SCIENTIFIC REALISM – the doctrine which believes that our best scientific theories tell us
about the unobservable structures of the world
10.2. A BRIEF HISTOR OF SCIENTIFIC REALISM
- P. Duhem argued for instrumentalism – the doctrine that theories are merely instruments
for generating reliable, empirically testable predictions
- Also defended a strong realist claim that physical theories reflect the true ontological order
of unobservables
- Logical empiricists, such as Schlick and Carnap, took different positions regarding realism
o Schlick was a kind of scientific realist
He argued that a verification theory of meaning does not lead to the claim
that only what we experience with our senses is real
He thought that we are able to penetrate the underlying structures of the
world
‘everything is real that the non-philosophizing scientist declares to be real’
o Carnap, on the other hand, was more of an anti-realist (empiricist)
He made a distinction between internal and external questions
Internal = questions about the existence of certain entities posed
within a certain framework
External = questions concerning the existence or reality of the
framework itself
There is no room for undecidable questions within a framework once the
framework is given and a concept (or term) has been assigned an empirical
meaning within that framework
The problem occurs since we are no longer sure if we can accept the
frameworks themselves (do we accept them because we think they are true
or because we see them as convenient devices for reaching some other goal
than truth?)
Carnap said that ‘an alleged statement of the reality of the
framework of entities is a pseudo-statement without cognitive
content’
the reasons for accepting the framework are not the reasons for
believing in the existence of the entities
He also made a distinction between pragmatic and epistemic reasons
Pragmatic = They refer to the reasons we have for using the
framework and one accepts a framework because of them
Epistemic = the reasons that make the assertion that something
exists more likely to be true
- E. Nagel argued that the problem of scientific realism is a linguistic confusion over
expressions
- Van Fraassen, on the other hand, claimed that the problem is does the science give us a true
picture of the world, unobservables, entities, processes etc. or does it stay on the surface
o Also, he thinks that there is no need to believe unobservables really exists in order
to be able to conduct science the way we normally do
o This position is incompatible with the scientific realism he developed his
constructive empiricism
, - Hempel (a logical positivist and empiricist) argued that theoretical terms are unnecessary if
the sole purpose of a theory is to establish deductive connections among observation
sentences
o He also claimed that science only needs observational terms and empirical
generalization
o Theoretical formulations cannot be replaced by expressions in terms of observables
only
- Many philosophers praised the high reliability of empirical predictions, which can only be
explained if we assume scientific realism to be true
10.3. PROBLEMS OF SCIENTIFIC REALISM
- The core argument of scientific realism is an inference of the only explanation which claims
that we grant the truth of a hypotheses since it is the only satisfactory explanation
o If we accept the fact that nothing can touch or be touched except the body, then
only the hypothesis of atoms can explain the various observable phenomena
- A. Fine claimed that we should accept and believe whatever scientists themselves believe
and accept
o There is no more evidence for the truth or falsehood of theories than what scientists
themselves present
- Another option is to defend entity realism – even if theories turn out to be false, the entities
they refer to might still exist
- Or we can turn to the structural realism – it is not the reference to entities which constitutes
enough continuity in science to justify being a realist, but rather the mathematical structures
or mathematical content of superseded theories
o This position depends upon the distinction between the nature and the structure of
unobservables
o Shortly, the best of our theories tells us about the structure of the unobservables
- Van Fraassen argues that the proper epistemic attitude towards theories postulating
unobservables is not one of believing in the existence of them
o He supports agnosticism Unobservable might exist but we cannot know that
(since we cannot observe them)
o Accepting a scientific theory involves as belief only that the theory is empirically
adequate
o ** he does not believe in the existence of electrons, but does believe in the
existence of Jupiter’s moons because he can see them
o He holds that theories have a truth value
o We never have sufficient epistemic reason to believe in the existence of
unobservables postulated in current successful scientific theories
o Empiricism explains everything realism explains but without implying any
metaphysical theories
o He offers a new theory of rationality according to which it can be rational to believe
in unobservables
o His view is called constructive empiricism
- There are other arguments that undermine scientific realism:
o The history of science illustrates that many of the once postulated unobservables do
not exist from the point of view of current science
, E.g. in the past, people believed that some objects burn because they
release phlogiston (unobservable substance), but today, no one believes in
phlogiston, but we believe that things burn because of oxygen
o The instrumental or empirical success of a theory does not necessarily provide truth
regarding existential claims about unobservables, and a lack of success cannot rule
out the truth of a theory’s ontology
o The pessimistic induction from the history of science – if so many successful theories
turn out to be ontologically false, then current successful theories may turn out to
be ontologically false too
o The final argument against the scientific realism is the thesis of underdetermination,
or the Duhem-Quine thesis
At any time there exist (or may exist) an infinite number of logically
incompatible but empirically equivalent theories
If that is true, there is no reason to believe that one ontology is better than
another
10.4. THE DEFENSE OF SCIENTIFIC REALISM
- According to Smart, a scientific realist and logical positivist, there are cosmic coincidences,
such as the fact that, if electrons did not exist, our predictions will still be true based on our
belief in their existence
o Therefore, we can choose to believe that:
1) the instrumental success of a theory is a cosmic coincidence
2) the theory depicts the unobservables of the world faithfully
- McMullin used the history of science to defend scientific realism
o The only way of explaining why the models of science function successfully in the
overcoming of anomalies is that they approximate in some way the structure of the
object
o scientific theories are successful since they have some relationship with parts of
the world they attempt to carve out scientific theories are often successful even
though they are about unobservables, and that must mean that they are true
o Only if we assume hypothesis to be true can we understand the success of science
we accept all that is not "falsified"
- H. Putnam talked about the indispensability argument when attacking fictionalism
o Fictionalism is a doctrine that although some concepts may be indispensable in the
scientific explanation of the behavior of observables, that does not mean that their
entities really exist because they can just be useful fictions
o He tried to prove scientific realism with two arguments:
the miracle argument – scientific realism is the only philosophy which does
not see the existence of science as a miracle
the indispensability argument – if something is true in one case, it doesn’t
have to be true in all cases
10.5. CONSTRUCTIVE EMPIRICISM
- Van Fraassen, in his Scientific Image, formulated the new philosophy of science – the
constructive empiricism
about the unobservable structures of the world
10.2. A BRIEF HISTOR OF SCIENTIFIC REALISM
- P. Duhem argued for instrumentalism – the doctrine that theories are merely instruments
for generating reliable, empirically testable predictions
- Also defended a strong realist claim that physical theories reflect the true ontological order
of unobservables
- Logical empiricists, such as Schlick and Carnap, took different positions regarding realism
o Schlick was a kind of scientific realist
He argued that a verification theory of meaning does not lead to the claim
that only what we experience with our senses is real
He thought that we are able to penetrate the underlying structures of the
world
‘everything is real that the non-philosophizing scientist declares to be real’
o Carnap, on the other hand, was more of an anti-realist (empiricist)
He made a distinction between internal and external questions
Internal = questions about the existence of certain entities posed
within a certain framework
External = questions concerning the existence or reality of the
framework itself
There is no room for undecidable questions within a framework once the
framework is given and a concept (or term) has been assigned an empirical
meaning within that framework
The problem occurs since we are no longer sure if we can accept the
frameworks themselves (do we accept them because we think they are true
or because we see them as convenient devices for reaching some other goal
than truth?)
Carnap said that ‘an alleged statement of the reality of the
framework of entities is a pseudo-statement without cognitive
content’
the reasons for accepting the framework are not the reasons for
believing in the existence of the entities
He also made a distinction between pragmatic and epistemic reasons
Pragmatic = They refer to the reasons we have for using the
framework and one accepts a framework because of them
Epistemic = the reasons that make the assertion that something
exists more likely to be true
- E. Nagel argued that the problem of scientific realism is a linguistic confusion over
expressions
- Van Fraassen, on the other hand, claimed that the problem is does the science give us a true
picture of the world, unobservables, entities, processes etc. or does it stay on the surface
o Also, he thinks that there is no need to believe unobservables really exists in order
to be able to conduct science the way we normally do
o This position is incompatible with the scientific realism he developed his
constructive empiricism
, - Hempel (a logical positivist and empiricist) argued that theoretical terms are unnecessary if
the sole purpose of a theory is to establish deductive connections among observation
sentences
o He also claimed that science only needs observational terms and empirical
generalization
o Theoretical formulations cannot be replaced by expressions in terms of observables
only
- Many philosophers praised the high reliability of empirical predictions, which can only be
explained if we assume scientific realism to be true
10.3. PROBLEMS OF SCIENTIFIC REALISM
- The core argument of scientific realism is an inference of the only explanation which claims
that we grant the truth of a hypotheses since it is the only satisfactory explanation
o If we accept the fact that nothing can touch or be touched except the body, then
only the hypothesis of atoms can explain the various observable phenomena
- A. Fine claimed that we should accept and believe whatever scientists themselves believe
and accept
o There is no more evidence for the truth or falsehood of theories than what scientists
themselves present
- Another option is to defend entity realism – even if theories turn out to be false, the entities
they refer to might still exist
- Or we can turn to the structural realism – it is not the reference to entities which constitutes
enough continuity in science to justify being a realist, but rather the mathematical structures
or mathematical content of superseded theories
o This position depends upon the distinction between the nature and the structure of
unobservables
o Shortly, the best of our theories tells us about the structure of the unobservables
- Van Fraassen argues that the proper epistemic attitude towards theories postulating
unobservables is not one of believing in the existence of them
o He supports agnosticism Unobservable might exist but we cannot know that
(since we cannot observe them)
o Accepting a scientific theory involves as belief only that the theory is empirically
adequate
o ** he does not believe in the existence of electrons, but does believe in the
existence of Jupiter’s moons because he can see them
o He holds that theories have a truth value
o We never have sufficient epistemic reason to believe in the existence of
unobservables postulated in current successful scientific theories
o Empiricism explains everything realism explains but without implying any
metaphysical theories
o He offers a new theory of rationality according to which it can be rational to believe
in unobservables
o His view is called constructive empiricism
- There are other arguments that undermine scientific realism:
o The history of science illustrates that many of the once postulated unobservables do
not exist from the point of view of current science
, E.g. in the past, people believed that some objects burn because they
release phlogiston (unobservable substance), but today, no one believes in
phlogiston, but we believe that things burn because of oxygen
o The instrumental or empirical success of a theory does not necessarily provide truth
regarding existential claims about unobservables, and a lack of success cannot rule
out the truth of a theory’s ontology
o The pessimistic induction from the history of science – if so many successful theories
turn out to be ontologically false, then current successful theories may turn out to
be ontologically false too
o The final argument against the scientific realism is the thesis of underdetermination,
or the Duhem-Quine thesis
At any time there exist (or may exist) an infinite number of logically
incompatible but empirically equivalent theories
If that is true, there is no reason to believe that one ontology is better than
another
10.4. THE DEFENSE OF SCIENTIFIC REALISM
- According to Smart, a scientific realist and logical positivist, there are cosmic coincidences,
such as the fact that, if electrons did not exist, our predictions will still be true based on our
belief in their existence
o Therefore, we can choose to believe that:
1) the instrumental success of a theory is a cosmic coincidence
2) the theory depicts the unobservables of the world faithfully
- McMullin used the history of science to defend scientific realism
o The only way of explaining why the models of science function successfully in the
overcoming of anomalies is that they approximate in some way the structure of the
object
o scientific theories are successful since they have some relationship with parts of
the world they attempt to carve out scientific theories are often successful even
though they are about unobservables, and that must mean that they are true
o Only if we assume hypothesis to be true can we understand the success of science
we accept all that is not "falsified"
- H. Putnam talked about the indispensability argument when attacking fictionalism
o Fictionalism is a doctrine that although some concepts may be indispensable in the
scientific explanation of the behavior of observables, that does not mean that their
entities really exist because they can just be useful fictions
o He tried to prove scientific realism with two arguments:
the miracle argument – scientific realism is the only philosophy which does
not see the existence of science as a miracle
the indispensability argument – if something is true in one case, it doesn’t
have to be true in all cases
10.5. CONSTRUCTIVE EMPIRICISM
- Van Fraassen, in his Scientific Image, formulated the new philosophy of science – the
constructive empiricism
