positions of the realists and the instrumentalists
INTRODUCTION
Modern science has
transformed the way we think of the world. Nature is no longer taken to be as
our senses indicate it to be. Entities and mechanisms invisible to the naked
eye (DNA, electromagnetic waves, protons, etc.) are said to populate the world,
and to cause observable phenomena. But why should we take scientific theories
to be true or approximately true? Answers to the above question have divided
philosophers of science into two major and conflicting groups. One group, the
realists, believe in the existence of a world independent of the mind of man
(it exists even if it cannot be perceived by the mind). This group also
believes that scientific theories do indeed describe, explain and predict
accurately this mind-independent world. Another group, the instrumentalists,
believe that scientific theories are mere instruments for predicting and
explaining observable phenomena. For them, only the observable world exists.
This
paper basically aims at presenting the positions of the realists and the instrumentalists.
The presentation shall be taken under these sub-headings; Historical
Background, Scientific Realism, Scientific Instrumentalism, Arguments for
Scientific Realism, Arguments against Scientific Realism, Arguments for
Scientific Instrumentalism, Arguments against Scientific Instrumentalism, An
Alternative and Conclusion.
HISTORICAL
BACKGROUND
Pierre Duhem notes that
the position of the instrumentalists could be traced to Plato who suggests that
astronomers ought to devise mathematical models that would serve as instruments
for explaining and predicting the elementary motions. [1] The instruments were to
function no more than to ‘save the phenomena’ (to explain and predict the
mind-independent world). This advice was heeded to by the Greek astronomers,
and in particular, by Claudius Ptolemy in his geometric constructions. Ptolemy
adopted, for instance, the instrumentalists’ position by stating that his
theories in astronomy were no more than fictions that enable him to explain and
predict the position of planetary bodies. Realism, according to Duhem, can be
traced to Aristotle. Theories, as seen by Aristotle, are meant not only to
‘save the phenomena’ but also in accord with the actual nature of things. John
BVL notes that the instrumentalists’ position of Ptolemy was continued by
Procius in the 5th century, Simplicius and John Philoponus in the 6th
century. [2] However, Joannis Votsis
notes that;
Arguably,
the scientific realism debate did not really come into its own…The first quarter
of the century (20th century) was marked by somewhat unsophisticated
general realism, most memorably the critical realism of Ray wood Sellars, formed
in reaction to the rampant idealism of the 19th century. The logical
positivists came to dominate the second quarter of the century. It was not
until the 1960s…that realism entered under the guidance of such figures as Karl
Popper, Grover Maxwell and JJC Stuart. At around this time, the historically
motivated work of Thomas Kuhn and Paul Feyerabend inspired new converts to, and
new versions of anti-realism. The Realists’ view was not kept at hay, however
with Hillary Putnam and Richard Boyd, amongst others keeping the debate alive
in the seventies. In the early eighties, the independent but equally powerful
critique by Bas Van Fraassen and Larry Laudan shaped old problems into new
challenges for the scientific realist. The debate as it is carried out today
owes much to this development, especially those that emerged after 1960.[3]
Stathis Pslilo also notes that
In
the first few decades of the 20th century, the philosophical
argument concerning realism (and instrumentalism) was cast in linguistic
terms-can theoretical terms denote anything? In the last few decades, the
argument has shifted to epistemic issues- can theories reveal truths about
observable (and obstruble) reality, or, should we believe that current theories
or approximately true? [4]
SCIENTIFIC
REALISM
Scientific realism is the
position in philosophy of science that states that the picture which science
gives us of the world is a true one, faithful in details, and the entities
postulated in science really exist. Scientific realism asserts that we can have,
and actually do have some knowledge of the observable and unobservable aspects
of the world. For the scientific realists, there is no sharp distinction
between the so-called ‘observables’ and ‘unobservables’. They both appear
‘observable’ to the eyes of the scientists (especially with the aid of
scientific tools).
Scientific realism also
posits that scientific theories claim true value. That is, claims made by
scientific theories about the observable and unobservable entities are true.
Some scientists however maintain that these claims are not typically or wholly
true, but rather approximately true. This is because the best scientific
theories are somewhat not completely capable of predicting future occurrences. Alexander Bird notes that for realists, scientific
theories;
a)
Can
be evaluated in terms of their truth or nearness to truth,
b)
Reasonably
aim at truth or nearness to truth,
c)
Have
success evidence in favour of being true,
d)
If
true, the unobservable entities they hypothesize should genuinely exist.
e)
If
true, they would explain the observable phenomena. [5]
Psillo notes that scientific realism
incorporates three thesis or stances, namely;
a)
The
metaphysical stance
b)
The
semantic stance
c)
The
episteme stance.[6]
The metaphysical stance asserts that the world has a definite and
mind-independent natural structure. The semantic
stance maintains that scientific theories are truth-centred descriptions of
their intended domains, both observable and unobservable. They are capable of
being true in value. The episteme stance
posits that entities posited by scientific theories do exist in the world, and
we can know them.
A.F. Chalmers
re-emphasizing the above-mentioned ideas notes that the objects of scientific
knowledge exist independently of the minds or acts of scientists, and that
scientific theories are true of that objective mind-independent world.[7] Chalmers identifies two
pivotal points of take-off for scientific realism. They are the metaphysical (independent existence of
certain entities) and epistemological
(we can know what exist and find out the truth of the theories that govern
them). Pierre Cruse maintains that scientific realism is assuredly the most
sensible position, noting that most of us would positively affirm that
scientific theories accurately describe the world, following from the fact that
scientists have evidence for the claims they make about the world. [8] For example, to hold that
electrons exist, scientists posit that if one places an ‘anode’ and a ‘cathode’
(two metal terminals connected to a wire carrying an electric current) inside a
vacuum tube, one can create a visible ‘ray’ that travels to the anode and the
cathode. This experiment shows the presence of electron, even though they are
not visible to the naked eyes. Cruse notes that J.J. Thompson was able to show
that these visible ‘rays’ consist of negatively charged particles. He also
measured successfully the mass/charge ratio of these particles.
Furthermore, Joanis
Votsis posits that the debate between realism and instrumentalism arouse the
following claims by realists,
a)
There
exists a mind-independent world
b)
Scientific
claims/theories have truth values
c)
Their
truth or falsity is determinable by recourse to the mind-independent world. [9]
Larry Laudan gives us a list of the major
claims of scientific realism, which are;
a)
Scientific
theories are typically (wholly) or approximately true.
b)
More
recent theories are closer to the truth than the earlier ones.
c)
All
the terms (observational and theoretical) of theories in modern science genuinely
refer,
d)
Scientific
theories in modern science ‘preserve’ the theoretical relations and referents
of earlier theories.
e)
New
theories explain the success of the predecessors. [10]
James Ladyman introduced the concept of
metaphysical realism to explain the fact that our ordinary language refer to,
and sometimes, say true things about a mind-independent world. [11] The aim of science for
scientific realism is to give us in its theories, a literally true story of
what the world is. However, the acceptance of a scientific theory involves the
belief that it is true.
Nonetheless, John Losse
identifies two types of realism, viz truth realism and entity realism.[12] By truth realism, he means that the theories scientists formulate are
true. He notes that scientists strive to formulate true theories that represent
the world. There is a world, independent of our mind, and theories sought to
explain and predict the world. Entity
realism posits that at least some of the cognitive objects discussed in
scientific theories do exist. Rom Hare notes the existence of three realms of
cognitive objects, viz;
Realm
One:
This denotes the existence of observable entities, entities observable by the
naked eye. For example, sun, moon, etc.
Realm
Two:
This denotes the existence of entities not presently observable, except with
the use of instruments, e.g. micro-organisms, veins, arteries, etc.
Realm
Three: This denotes the existence of entities that cannot be
detected by even the best devices, e.g. neutrinos. They can only be detected by
observing what they do.
In summary, for
scientific realism, science aims at producing and has succeeded in producing
true/approximately true claims about the observable and unobservable aspects of
the world.
SCIENTIFIC
INSTRUMENTALISM
It is important to state
here that instrumentalism is a type of anti-realism. Anti-realism is the
position that we cannot know whether any of the claims made by scientific
theories about the mind-independent world is true or approximately true.
Instrumentalism shares the same view as presented by the general field,
anti-realism. Instrumentalism regards theories not as attempts to describe or
explain the world, but as instruments of making predictions. Bird regards it as
a category mistake to ask about the truth of a theory. He maintains that what
we should be asking is about its empirical adequacy. A theory is empirically
adequate when everything it asserts about the observable world is true.
Bird uses the analogy of a black box to
illustrate what instrumentalism is;
One
puts into the box information regarding observed background conditions, and the
box generates predictions regarding what we will observe. What he wants from
such a black box is that if the input information is accurate then the
prediction or yield will be accurate. We are not especially concerned with the
mechanism inside the box. That can be nothing so long as it …In particular;
there is no requirement that it depicts what the world is. Indeed, it does not
make use of this mechanism to say that it does or does not depict the world. It
is merely an instrument. [13]
Input
(observational----------Theory-------Output (observable phenomena)
John Losse maintains that
instrumentalists see scientific theories as no more than calculating devices
that facilitate the organisation and prediction of statements about
observables.[14]
It is pertinent to note that instrumentalists posit the existence of only the
observables, that is, only those entities which are determinable by the unaided
human senses. Chalmers maintains that instrumentalism distinguishes
‘observables’ from ’theoreticals’.[15] He notes that for the
instrumentalists, science is concerned with providing theories that serve as
instruments for connecting or linking two or more sets of observable situations.
In summary,
instrumentalism holds that scientific theories and models of the world are
valued only in the sense that they are useful in predicting events, and
explaining data consistently making no claim that anything they describe
actually exist: scientific theories should be thought of primarily as tools for
solving practical problems rather than as meaningful description of the actual
world. Instrumentalism is the opinion that we can only observe the world from
our natural way of perception, and that we lack the appropriate language to
describe it. We therefore resort to the use of theories. Science,
instrumentalists contend, cannot explain the world with the use of language;
therefore scientists make use of theories, which are nothing more than vehicles
which they employ to convey the idea concerning the realities they aim to
explain. The aim of science, for the instrumentalist, is to postulate theories
that are devices/instruments for relating situations that are observable to
man.
Instrumentalists view
theories postulated by science as nothing but rules that enable us link an
observable entity to another. For the instrumentalists, observable things like
iron fillings, planets and light rays are real, thus they exist, but consider
magnetic, electric and gravitational fields as fictions. Therefore, the goal of
science for the instrumentalists, is not concerned with establishing what may
be existing outside or beyond the field of observation; science lacks the means
to bridge the gap between the observables and unobservable.
ARGUMENTS
FOR REALISM
The literature in
scientific realism presents two major arguments in support of the positions of
realists. They include; (a) The ‘No-Miracle Argument’ (NMA), and (b) Inference
to the Best Explanation (IBE).
THE
‘NO-MIRACLE ARGUMENT’ (NMA): This was proposed by J.J.C
Smart and Hilary Putnam. Putnam states that “scientific realism is the only
philosophy of science that does not make the success of science a miracle.”[16] He argued that it would
be a miracle, for instance, if given the empirical success of scientific
theories, there are at least no approximately true theories. Furthermore, the
‘NMA’ aims to defend the realists’ claim that successful scientific theories
should be accepted as true (or approximately true) description of the world, in
both its observable and unobservable spheres. Furthermore, J.J.C Smart,
presenting his ‘cosmic coincidence and the success of science’ (this position
is essentially the same as the ‘NMA’, thus they are mostly considered as one in
literature of scientific realist), states that instrumentalists must believe in
cosmic coincidence.[17]
The NMA can be captured
thus: suppose that a friend tells you in confidence that the chairman of your company
has sacked two workers. This supposes that eventually these two workers were
sacked. In that case, it is possible that your friend’s theory was false, that
the workers were sacked by chance and not because he was actually privy to the
information that led to their sack. However, a more reasonable conclusion seems
to be that your friend’s theory is actually true. It is important to note that
the realists posit that many scientific theories throughout history have led to
further surprising and novel predictions, which in fact are true. Thus, the NMA
urges us to conclude from the fact that some certain theories in science have
been successful in predicting phenomena, they are necessarily true, and that
the entities they postulate exist.
INFERENCE
TO THE BEST EXPLANATION (I.B.E): Joannis notes that this
argument is attributed to C.S. Pierce.[18] The argument goes thus;
let us suppose that we have evidence E, and we consider several hypotheses, H
and H1. IBE says that we should infer H rather H1 exactly if H is a better
explanation of E than H1 is. Simply put, we observe evidence E, theory H is the
best explanation of evidence E, and therefore theory H is true. Thus, realists
maintain that scientific theories do truly (or approximately) infer the real
world, observed from evidence.
ARGUMENTS
AGAINST REALISM
Bas Van Fraassen objects
the NMA.[19]
He maintains that NMA poses an unfair dilemma. NMA preaches that we either
uphold scientific realism or consider the success of science a miracle. He
notes further that we might need to account for the success of science but denies
that scientific realism is the only or best account. He argues, using the
evolution analogy, that scientific theories struggle for survival. Those once
accepted as true are replaced by newer ones, as could be found in Aristotle’s
science of the planets. Thus, for Fraassen, theories need not to be true or
approximately true but empirically successful or adequate. A theory is
successfully adequate when everything it asserts about the observable world is
true.
According to Alexander, Conte
criticised realism thus: if science holds that there are unobservable or hidden
entities, it is borrowing from faith, thus relating science to theology.[20] Furthermore, he says that
Sir Benjamin Broide shares similar stance with Conte. He notes that scientists
(chemists) see by the chemical reaction what quantities of substances mixed
together exhibit during experiment. Furthermore, Larry Laudan criticising the
IBE notes that the claim held by realists that successful prediction is truth,
should not be accepted, for it does not serve as an indicator for truth. Laudan
writes, criticising realists’ idea of truth,
No
one has been able even to say what it would mean to be ‘closer to the truth’,
let alone to offer criteria for determining how we could assess such proximity.[21]
Jarret Leplin notes that
the recent direction of theoretical physics creates difficulties for scientific
realism. He is of the opinion that what can be done in case of molecules and
electrons cannot be done in the case of entities such as gravitons, magnetrons
and quarks.[22]
ARGUMENTS
FOR SCIENTIFIC INSTRUMENTALISM
UNDER
DETERMINATION OF THEORY BY EVIDENCE: This argument asserts
that for any given body of evidence, they are infinite competing theories that
can explain it, so that no one evidence can uniquely determine a scientific
theory. Simply put, the reference from the evidence to the theory is not
deductively valid.[23] David Hume, for instance,
argued that no matter how many occurrences of an event we observe, we still
cannot draw universal statements from it. This view holds that no matter how
much evidence we have, we will always have infinity many theories to choose
from, thus we will never be able to uphold any one theory as the true one. It
can be put thus: for any given body of observational evidence there are
infinite empirical equivalent theories that diverge in their theoretical
claims.
THE
DAMNING HISTORICAL RECORD OF SCIENCE: Laudan notes that
history of science is punctuated by the withdrawal of hitherto successful
theories.[24]
The argument maintains that it is impossible to compare the paradigms or
concepts across history. This shows that there is no continuity between them. This
change involves radical shifts in which essential theoretical components are
thrown away, thus rendering scientific knowledge a cumulative nature, rather
than progressiveness towards the truth.
In
summary, this argument claims that scientific theories in modern science do not
preserve at least some of the theoretical relations and referents of earlier
theories. Some examples cited by instrumentalists to advance this argument
include the claims by Galen that blood was provided in the liver, pumped by the
heart, and the body then simply consumes it. Another is the scientific claim by
Aristotle that the sun moves around the earth.
ARGUMENTS
AGAINST SCIENTIFIC INSTRUMENTALISM
Chalmers notes that instrumentalism can be
criticised for making a wrong distinction between observational entities and
theoretical concepts.[25] Instrumentalists assert
that theoretical concepts/entities do not exist because they are unobservable. However,
Chalmers notes that for the fact that new scientific discoveries have been made
from theories and the so called ‘theoretical fiction’ must have been a great
surprise for instrumentalists. For example, in Chemistry, Kekule posited that
benzene consist of closed rings of atoms. Today, these closed rings of atoms
can be seen with the electron microscope.
Again, Chalmers gives
another criticism, in that, it is wrong to call scientific theories as mere
instruments, and thus rejecting that they are true or approximately true. Many
scientific theories have been postulated which actually and truly describe the
world and make accurate predictions. Examples include the possibility of using
electron microscope to observe electrons and how they operate.
AN
ALTERNATIVE TO REALISM AND INSTRUMENTALISM
Arthur Fine has suggested
an alternative to both scientific realism and instrumentalism.[26] He calls it the Natural Ontological Attitude (NOA),
which he describes as non-realism. NOA does not impose a general interpretive
scheme in science. It does not set any aim for science. The NOA argues that a
realist’s or an instrumentalist’s aim for science is not natural because they
add metaphysical touch to science, and this is unacceptable.
Fine asserts that both
realists and anti-realists share a basic position about everyday things and
scientific statements. (Instrumentalism is a form of anti-realism). Realists
and anti-realists both trust the evidence of their senses that tables, chairs
and other people are present before us and in some sense exist. They also trust
the assertion of science that protons and electrons exist and have the size,
mass and charge science assigns them. Fine writes
It
seems to me that when we contrast the realist and the anti-realist in terms of
what they each want to add to the core position, a third alternative
emerges—and an attractive one at that. It is the core position itself, and all
by itself…at heart, the grip of realism only extends to the homely connection
of everyday truths with scientific truths, and that good sense dictates our
acceptance of the one on the same basis as our acceptance of the other, then
the homely line makes the core position, all by itself, a compelling one....[27]
Fine rejected realism
because of the realist's desire to connect truths about an entity (say the mass
or charge of an electron) to an actual, existing entity (electron). It is
permissible to believe in the properties of an electron, Arthur argues, but not
in the electron itself as the bearer of those properties. That is the mistake
realists make. Yet Fine admits that the working scientist believes that those
things which the theories refer to actually exist. In addition, Fine concedes
that practitioners of science do not need the goals, interpretations or
justifications of science that theorists can provide. And although scientists
may discover more and more properties/facts about an entity, Fine insists that
we should not confuse successive advances in our knowledge of an entity with
closer approximations as to what that entity actually is.
Fine also criticised
anti-realists. For him, they make the same basic mistake as the realists since
they rely on metaphysical or epistemological hearing aids to hear the voice of
science. Only NOA is immune from these delusions and distractions. Fine posits
that truth is a semantical concept and not an ontological or metaphysical
concept. He argues that those who wish to ground "truth" in realism
and antirealism are all making the same fundamental mistake. Fine urges us to
embrace NOA, and be non-judgmental and heuristic in our pursuit of knowledge.
He also urges us to reject the concept of "truth" as a gold standard
to which all knowledge must be compared or evaluated.
CONCLUSION
Given the above
positions, it follows that realism and
instrumentalism debates about two things: the aim of science and the nature of
scientific theories/entities. For the realists, science should provide us with
truths or approximate truths, while for the instrumentalists, science should be
effective, efficient and pragmatic (extremely empirical). Furthermore, realists
posit that theories are true and unobservable entities are real. However, instrumentalists
posit that theories are mere instruments and that only observable entities are
real. Again, if these unobservable entities are real, they should be able to
explain phenomenon; its effective interaction with reality.
[4] Cf. Stathis Pslilo, Scientific realism,:How science tracks truth
(New York: Routledge, 1999), p. 16
[7] Cf. A. F Chalmers, What is this thing called science?
(Cambridge: Hackett Publishing Company Inc, 1999), pp. 230-235
[11]Cf. James Ladyman, Understanding philosophy of science,
(New York: Routledge, 2002), pp. 158-160
[12] Cf. John Losse, A historical introduction to the philosophy
of science, (New York: Oxford university press, 2001), pp.252-256
[14] Cf. John Losse, A historical introduction to the philosophy
of science, (New York, Oxford university press, 2001), pp.253
[26]Cf.
Arthur Fine, The Shakey Game (Chicago:
University of Chicago Press, 1986), pp. 112-50,
[27]Arthur
Fine, The Shakey Game, pp. 129-130
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