Philosophy of science
The philosophy of science is the branch of philosophy which deals with the study of science (in the sense of "natural science"). Key topics include the motivation for scientific approaches; 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.
This article is not exhaustive; it covers only those topics that are seen as central by all of the major philosophies of science. As with the philosophy of mathematics, there tend to be 'schools' of scientific thought, each of which adheres to its own principles. 'Each of these in future deserves its own article(s)'.
One of the most central principles in the philosophy of science is that of empiricism, or dependence on evidence. Some claim that empiricism is necessary for science -- perhaps most notably the British empirical school. Essentially, we gather information in ways that ultimately lead back to our senses, via empirical methods that many humans are capable of experiencing. Once reproduced widely enough by many scientists, this information becomes evidence, upon which we base our explanations of how things work.
Given enough reliable evidence, one can then use the principles of reason and logic (and other quasi-empirical methods which complement the strictly empirical structure of experiment but which lead back to our sense of truth and invoke key conceptual metaphors) to work these explanations into a coherent, self-consistent structure. The degree to which one can trust such methods is a major concern of the philosophy of science. Modern definitions of reason and logic certainly have not been applied through the entire history of the scientific method, but results achieved by those earlier methods are still valid, and are very rarely invalidated. This suggests that our unchanged conceptual metaphors (such as the ideas of similarity and sufficiency that drive counting and measuring) may be more deeply rooted than any of our explanations of our thinking processes as humans, and as scientists.
Another central, but increasingly challenged, premise in the philosophy of science is the principle of falsifiability, first formally discussed by Karl Popper. 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.
Critics of this principle tend to follow one of two lines of argument. Firstly, they argue that theories are often accepted and built upon as a result of their eloquence and elegance, e.g. mathematical simplicity, and that experimental evidence rarely 'falsifies' but rather limits the application of such theories. These arguments tend to focus on the weaknesses of the logical law of excluded middle, i.e. 'no gray areas', on which the principle of falsifiability depends.
The second criticism is that many scientific theories are simply not so falsifiable, e.g. those in the social sciences which are still called 'sciences', and very abstract models, e.g. string theory, Standard model in particle physics which can only be empirically tested by very expensive tests and specialized apparatus, and so are amenable to a great deal of cultural pressure and groupthink all pushing the scientists to agree, and not to test the central tenets of a theory, if such tests are feasible at all. These arguments tend to focus on the trust of the general public in the scientific community and its works, and the degree to which falsifiability actually drives what is called 'science' in the academies, research labs, textbooks, and governments.
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.
The idea of reductionism continues to recur in the philosophy of science - essentially, it refers to the limits of the process of breaking up phenomena or processes into smaller and smaller parts and assuming that the whole can be understood in this way.
A high degree of such reduction is essential to science itself, else it would be impossible to determine significant versus not significant measurements, differences between apparatus and of experiments, etc.. What is more, it would be impossible to rely on mathematics if one refused to reduce phenomena to elementary concepts such as sets, numbers, or points.
It should be noted however that networks contain more information than the sum of their component parts. Division of networked phenomena into subcomponents through analytic choice is necessarily information-destructive. Information theory can be used to calculate the magnitude of information loss.
Most objections to reductionism are in fact references to what Daniel Dennett calls greedy reductionism, which he claims is just 'bad science', seeking to find explanations which are appealing or eloquent, rather than those that are of use in predicting natural phenomena. It is hard to separate the issues involved with objections to falsifiability or misuse of Occam's Razor, from those which arise due to over-reduction of a complex set of phenomena. All such errors of method or choice of theories could be said to actually be errors of greedy reduction.
A critical theme 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 worls in which we live. The acceptance of knowledge as if it were absolutely 'true' and unquestionable (in the sense of theology or ideology) is rejected by scientists.
However, it is common for members of the public to have precisely the opposite view of science; many lay people seem certain that scientists are making claims of infallibility. Some in the scientific and skeptical community are converned about the wide disaprity between how scientists work, and how their work is perceived. Many scientists are thus involved in public education campaigns to educate lay people in high schools and colleges about scientific skepticism and the scientific method.
It is often stated that the natural sciences in our society owe their success to the diligent application of the scientific method. Its proponents claim that it is rational and logical. However, among some social scientists and writers there is some debate as to the nature and utility of science.
Imre Lakatos believes that people studying the natural world have not actually produced reliable scientific knowledge; rather, they have only constructed historical accounts to suit their pet philosophies and methods. This "rational reconstruction" of the history of science is then used to justify certain ideological assumptions, producing what might tentatively be called a mythology of science. His work is rejected as invalid by the majority of scientists, engineers and historians.
Philosopher Paul Feyerabend argued that descriptions of the scientific method often do not match how scientific discoveries have actually occurred in history. Feyerabend objected to any single prescriptive scientific method on the grounds that science has no single aim. Without a fixed ideology, or the introduction of religious tendencies, the only approach which does not inhibit progress (using whichever definition of progress you see fit) is "anything goes".
See also: History of science and technology -- sociology of science -- scientific method -- epistemology -- philosophy of mathematics -- scientism -- science studies
causation --
duality --
faith and rationality --
free will and determinism --
philosophy of mathematics --
problem of the criterion --
scientific explanation --
the reality of unobservables --
Empiricism
Falsifiability
Occam's Razor
Reductionism
Perception versus reality
History
Criticisms of science
Philosophy of Science topics
References
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