Philosophy of Science

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 organisation 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.

Because, generally for every theory there are an infinite number of variations 
which are equally consistent with the current data, but which predict very 
different outcomes in some circumstances, Occam's razor is used implicitly 
in every instance of scientific research. As an examlpe consider Newton's 
famous theory that "for every action there is an equal and oposite reaction." 
An alternative theory would be that "for every action there is an equal and 
opposite reaction, except on the 12 of January 2055 when the reaction will 
be of half intensity." This seemingly absurd addition, violates the Occam's 
Razor principle because it as a gratuitious addition, along with an infinite 
number of other alternative theories. Indeed without a rule like Occam's 
Razor there would never be any philosophical or practical justification for 
scientists to advance any theory over it's infinite competitors, and science 
would have no predictive power at all.

Though Occam's Razor is the most widely used and philosphically understandable 
extra-evidentary theory selection rule, there are now similar 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.


ritiques 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."