From Wikipedia, the free encyclopedia.
The philosophy of science is the branch of philosophy
which studies the philosophical foundations, presumptions
and implications of science
both of the natural
sciences like physics
and biology
and the social
sciences such as psychology
and economics.
In this respect, the philosophy of science is closely
related to epistemology
and ontology.
It seeks to explain such things as: the nature of
scientific statements and concepts; the way in which they
are produced; how science explains, predicts and harnesses
nature; the means for determining the validity of
information; the formulation and use of the scientific
method; the types of reasoning used to arrive at
conclusions; and the implications of scientific methods
and models for the larger society, and for the sciences
themselves.
One view is that all sciences have an underlying
philosophy regardless of claims to the contrary:
- There is no such thing as philosophy-free
science; there is only science whose philosophical
baggage is taken on board without examination. —Daniel
Dennett, Darwin's
Dangerous Idea, 1995.
This article, as any, is not exhaustive, yet covers
arguably the most common ground in the Philosophy of
Science.
Nature of scientific statements and concepts
Science makes assumptions about the way the world is,
and the way in which theory relates to the world.
Empiricism
A central concept in the philosophy of science is empiricism,
or dependence on evidence. Empiricism is the view that
knowledge derives from experience of the world. In this
sense, scientific statements are subject to and derived
from our experiences or observations. Scientific theories
are developed and tested through experiments
and observations,
via empirical
methods. Once reproduced widely enough this
information counts as evidence, upon which the
scientific community bases its explanations
of how things work.
Observations involve perception,
and so are themselves cognitive acts. That is,
observations are themselves embedded in our understanding
of the way in which the world works; as this understanding
changes, the observations themselves may apparently
change.
Scientists attempt to use induction,
deduction
and quasi-empirical
methods, and invoke key conceptual
metaphors to work observations into a coherent,
self-consistent structure.
Scientific realism and instrumentalism
Scientific
realism, or naïve
empiricism, is the view that the universe really is as
explained by scientific statements. Realists hold that
things like electrons and magnetic fields actually exist.
It is naïve in the sense of taking scientific models at
face value, and is the view that most scientists adopt.
In contrast to realism, instrumentalism
holds that our perceptions, scientific ideas and theories
do not necessarily reflect the real world accurately, but
are useful instruments to explain, predict and control our
experiences. To an instrumentalist, electrons and magnetic
fields are convenient ideas that may or may not actually
exist. For instrumentalists, empirical method is used to
do no more than show that theories are consistent with
observations. Instrumentalism is derived in part from John
Dewey's pragmatism.
Social constructivism
One area of interest among historians, philosophers,
and sociologists of science is the extent to which
scientific theories are shaped by their social and
political context. This approach is usually known as social
constructivism. Social constructivism is in one sense
an extension of instrumentalism that incorporates the
social aspects of science. In its strongest form, it sees
science as merely a discourse between scientists, with
objective fact playing a small role if any. A weaker form
of the constructivist position might hold that social
factors play a large role in the acceptance of new
scientific theories.
On the stronger account, the existence of Mars the
planet is irrelevant, since all we really have are the
observations, theories and myths, which are all themselves
constructed by social interaction. On this account,
scientific statements are about each other, and an
empirical test is no more than checking the consistency
between different sets of socially constructed theories.
This account rejects realism. It becomes difficult, then,
to explain how science differs from any other discipline;
equally, however, it becomes difficult to give an account
of the extraordinary success of science in producing
usable technology.
On the weaker account, Mars the planet might be said to
have a real existence, separate and distinct from our
observations, theories and myths about it. Although
theories and observations are socially constructed, part
of the construction process involves ensuring a
correspondence of some sort with this reality. On this
account, scientific statements 'are' about the real world.
The crucial issue for this account is explaining this
correspondence. What justification is there for claiming
that photos from the latest probe are in some sense more
real than the Roman
myths about Mars? It is important, therefore, for
Social Constructivists to consider how scientific
statements are justified.
Analysis and reductionism
Analysis
is the activity of breaking an observation or theory down
into simpler concepts in order to understand it. Analysis
is as essential to science as it is to all rational
enterprises. It would be impossible, for instance, to
describe mathematically the motion of a projectile
without separating out the force of gravity,
angle of projection and initial velocity. Only after this
analysis is it possible to formulate a suitable theory of
motion.
Reductionism
in science can have several different senses. One type of
reductionism is the belief that all fields of study are
ultimately amenable to scientific explanation. Perhaps an
historical event might be explained in sociological and
psychological terms, which in turn might be described in
terms of human physiology, which in turn might be
described in terms of chemistry and physics. The
historical event will have been reduced to a physical
event. This might be seen as implying that the historical
event was 'nothing but' the physical event, denying the
existence of emergent phenomena.
Daniel
Dennett invented the term greedy
reductionism to describe the assumption that such
reductionism was possible. He claims that it is just 'bad
science', seeking to find explanations which are
appealing or eloquent, rather than those that are of use
in predicting natural phenomena.
Arguments made against greedy reductionism through
reference to emergent
phenomena rely upon the fact that self-referential systems
can be said to contain more information
than can be described through individual analysis of their
component parts. Examples include systems that contain strange
loops, fractal
organization and strange
attractors in phase
space. Analysis of such systems is necessarily
information-destructive because the observer must select a
sample of the system that can be at best partially
representative. Information
theory can be used to calculate the magnitude of
information loss and is one of the techniques applied by Chaos
theory.
The justification of scientific statements
The most powerful statements in science are those with
the widest applicability. Newton's Third Law — "for
every action there is an opposite and equal reaction"
— is a powerful statement because it applies to every
action, anywhere, and at any time.
But it is not possible for scientists to have tested
every incidence of an action, and found a reaction. How is
it, then, that they can assert that the Third Law is in
some sense true? They have, of course, tested many, many
actions, and in each one have been able to find the
corresponding reaction. But can we be sure that the next
time we test the Third Law, it will be found to hold true?
Induction
One solution to this problem is to rely on the notion
of induction.
Inductive reasoning maintains that if a situation holds in
all observed cases, then the situation holds in all such
cases. So, after completing a series of experiments that
support the Third Law, one is justified in maintaining
that the Law holds in all cases.
Explaining why induction commonly works has been
somewhat problematic. One cannot use deduction, the usual
process of moving logically from premise to conclusion,
because there is simply no syllogism that will allow such
a move. No matter how many times 17th Century biologists
observed white swans,
and in how many different locations, there is no deductive
path that can lead them to the conclusion that all swans
are white. This is just as well, since, as it turned out,
that conclusion would have been wrong. Similarly, it is at
least possible that an observation will be done tomorrow
that shows an occasion in which an action is not
accompanied by a reaction; the same is true of any
scientific law.
One answer has been to conceive of a different form of
rational argument, one that does not rely on deduction.
Whereas deduction allows one to formulate a specific truth
from a general truth (all crows are black; this is a crow;
therefore this is black), induction merely allows one to
formulate a probability of truth from a series of specific
observations (this is a crow and it is black; that is a
crow and it is black; therefore our sample shows crows are
black in general).
The problem
of induction is one of considerable debate and
importance in the philosophy of science: is induction
indeed justified, and if so, how?
Falsifiability
Another way to use logic to justify scientific
statements, first formally discussed by Karl
Popper, is falsifiability.
This principle states that in order to be useful (or even
scientific at all), a scientific statement ('fact',
theory, 'law', principle, etc) must be falsifiable,
i.e. able to be proven wrong. Without this property, it
would be difficult (if not impossible) to test a
scientific statement against the evidence. Falsification's
aim is to re-introduce deductive reasoning into the
debate. It is not possible to deduce a general statement
from a series of specific ones, but it is possible for one
specific statement to prove that a general statement is
false. Finding a black
swan might be sufficient to show that the general
statement 'all swans are white' is false.
Falsifiability neatly avoids the problem of induction,
because it does not make use of inductive reasoning.
However, it introduces its own difficulties. When an
apparent falsification occurs, it is always possible to
introduce an addition to a theory that will render it
unfalsified. So, for instance, ornithologists might have
simply argued that the large black bird found in Australia
was not a member of the genus Cygnus, but of some other,
or perhaps some new, genus.
The problem with falsificationism is that scientific
theories are simply never falsifiable. That is, it is
always possible to add ad hoc hypotheses to a
theory to save it from falsification. A value judgment is
therefore involved in the rejection of any theory.
Coherentism
Induction and Falsification both attempt to justify
scientific statements by reference to other specific
scientific statements. Both must avoid the problem
of the criterion, in which any justification must in
turn be justified, resulting in an infinite regress. The regress
argument has been used to justify one way out of the
infinite regress, foundationalism.
Foundationalism claims that there are some basic
statements that do not require justification. Both
induction and falsification are forms of foundationalism
in that they rely on basic statements that derive directly
from observations.
The way in which basic statements are derived from
observation complicates the problem. Observation is a
cognitive act; that is, it relies on our existing
understanding, our set of beliefs. An observation of a transit
of Venus requires a huge range of auxiliary beliefs,
such as those that describe the optics of telescopes, the
mechanics of the telescope mount, and an understanding of
celestial mechanics. At first sight, the observation does
not appear to be 'basic'.
Coherentism
offers an alternative by claiming that statements can be
justified by their being a part of a coherent system. In
the case of science, the system is usually taken to be the
complete set of beliefs of an individual or of the
community of scientists. W.
V. Quine argued for a Coherentist approach to science.
An observation of a transit of Venus is justified by its
being coherent with our beliefs about optics, telescope
mounts and celestial mechanics. Where this observation is
at odds with one of these auxiliary beliefs, an adjustment
in the system will be required to remove the
contradiction.
Occam's Razor
Occam's
Razor is another notable touchstone in the philosophy
of science. William
of Occam (or Ockhegm or several other spellings)
suggested that the simplest account which 'explains'
the phenomenon is to be preferred. He did not suggest that
it would be true, or even more likely to be true, though
'simpler' has very often turned out to be more likely to
be right (in hindsight) than 'more complex'.
Occam's Razor has usually been used just as a rule
of thumb for choosing between equally 'explanatory'
hypotheses (ie, theories) about one or more observed
phenomena. However, it is rare that two theories explain equally,
so its use has been limited. There are now mathematical
approaches based on information
theory that balance explanatory power with simplicity.
One such is minimum
message length inference.
Occam's Razor is often abused and cited where it is
inapplicable. It does not say that the simplest account is
to be preferred regardless of its capacity to explain
outliers, exceptions, or other phenomena in question. The
principle of falsifiability requires that any exception
that can be reliably reproduced should invalidate the
simplest theory, and that the next-simplest account which
can actually incorporate the exception as part of the
theory should then be preferred to the first.
Social accountability
Scientific infallibility
A critical question in science is, to what degree the
current body of scientific knowledge can be taken as an
indicator of what is actually 'true' about the physical
world in which we live. The acceptance of knowledge as if
it were absolutely 'true' and unquestionable (in the sense
of theology
or ideology)
is called scientism.
However, it is common for members of the public to have
the opposite view of science — many lay people believe
that scientists are making claims of infallibility.
Science serves in the process of consensus
decision making by which people of varying moral and
ethical views come to agree on 'what is real'. In secular
and technological societies, without any stronger
conception of reality based on other shared ethical or
moral or religious grounds, science has come to serve as
the primary arbiter in disputes. This leads to the abuse
of scientific dialogue for political or commercial ends.
Concerned about the wide disparity between how
scientists work, and how their work is perceived has led
to public campaigns to educate lay people about scientific
skepticism
and the scientific
method.
Critiques of science
Paul
Feyerabend argued that no description of scientific
method could possibly be broad enough to encompass all the
approaches and methods used by scientists. Feyerabend
objected to prescriptive scientific method on the grounds
that any such method would stifle and cramp scientific
progress. Feyerabend claimed, "the only principle
that does not inhibit progress is: anything goes."
See also
History
Philosophy of science topics
References
- Snyder, Paul, Toward One Science: The
Convergence of Traditions, St Martin's Press,
1977, cloth ISBN
0-312-81011-3, paper ISBN
0-312-81012-1.
- Van Fraassen, Bas C., The Scientific Image,
Oxford: Clarendon Press, 1980, ISBN
0-198-24427-4.
- Boyd, R.; Paul Gasper; J. D. Trout, Ed. (1991) The
Philosophy of Science. Cambridge, Massachusetts,
Blackwell Publishers.
- Harre, R. (1972) The Philosophies of Science: An
Introductory Survey. London, Oxford University Press.
- Klemke, E. et. al. Ed. (1998). Introductory Readings
in The Philosophy of Science. Amherst, New York,
Prometheus Books.
- Losee, J. (1998). A Historical Introduction to The
Philosophy of Science. Oxford, Oxford University
Press.
- Pap, A. (1962). An Introduction to the Philosophy of
Science. New York, The Free Press.
- Papineau, D. Ed. (1997). The Philosophy of Science.
Oxford Readings in Philosophy. Oxford, Oxford
University Press.
- Rosenberg, A. (2000). Philosophy of Science: A
Contemporary Introduction. LOndon, Routledge.
- Salmon, M. H. et. al. (1999). Introduction to the
Philosophy of Science: A Text By Members of the
Department of the History and Philosophy of Science of
the University of Pittsburgh. Indianapolis, Hacket
Publishing Company.
- Newton-Smith, W. H. Ed. (2001). A Companion To The
Philosophy of Science. Blackwell Companions To
Philosophy. Malden, Massachusetts, Blackwell
Publishers.
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