No miracles argument One of the main arguments for scientific realism centers on the notion that scientific knowledge is progressive in nature, and that it is able to predict phenomena successfully. Many scientific realists (e.g.,
Ernan McMullin,
Richard Boyd) think the operational success of a theory lends credence to the idea that its more unobservable aspects exist, because they were how the theory reasoned its predictions. For example, a scientific realist would argue that science must derive some
ontological support for atoms from the outstanding phenomenological success of all the theories using them. Arguments for scientific realism often appeal to
abductive reasoning or "inference to the best explanation" (Lipton, 2004). For instance, one argument commonly used—the "miracle argument" or "no miracles argument"—starts out by observing that scientific theories are highly successful in predicting and explaining a variety of phenomena, often with great accuracy. Thus, it is argued that the best explanation—the only explanation that renders the success of science to not be what
Hilary Putnam calls "a miracle"—is the view that our scientific theories (or at least the best ones) provide true descriptions of the world, or approximately so.
Bas van Fraassen replies with an evolutionary analogy: "I claim that the success of current scientific theories is no miracle. It is not even surprising to the scientific (Darwinist) mind. For any scientific theory is born into a life of fierce competition, a jungle red in tooth and claw. Only the successful theories survive—the ones which in fact latched on to actual regularities in nature." (
The Scientific Image, 1980) It has been argued that the no miracles argument commits the
base rate fallacy.
Pessimistic induction Pessimistic induction, one of the main arguments against realism, argues that the history of science contains many theories once regarded as empirically successful but which are now believed to be false. Additionally, the history of science contains many empirically successful theories whose unobservable terms are not believed to genuinely refer. For example, the effluvium theory of static electricity (a theory of the 16th Century physicist
William Gilbert) is an empirically successful theory whose central unobservable terms have been replaced by later theories. Realists reply that replacement of particular realist theories with better ones is to be expected due to the progressive nature of scientific knowledge, and when such replacements occur only superfluous unobservables are dropped. For example,
Albert Einstein's theory of
special relativity showed that the concept of the
luminiferous ether could be dropped because it had contributed nothing to the success of the theories of
mechanics and
electromagnetism. On the other hand, when theory replacement occurs, a well-supported concept, such as the concept of
atoms, is not dropped but is incorporated into the new theory in some form. These replies can lead scientific realists to
structural realism.
Constructivist epistemology Social constructivists might argue that scientific realism is unable to account for the rapid change that occurs in
scientific knowledge during periods of
scientific revolution. Constructivists may also argue that the success of theories is only a part of the construction. However, these arguments ignore the fact that many scientists are not realists. During the development of
quantum mechanics in the 1920s, the dominant philosophy of science was
logical positivism. The alternative realist
Bohm interpretation and
many-worlds interpretation of quantum mechanics do not make such a revolutionary break with the concepts of
classical physics.
Underdetermination problem Another argument against scientific realism, deriving from the
underdetermination problem, is not so historically motivated as these others. It claims that observational data can in principle be explained by multiple theories that are mutually incompatible. Realists might counter by saying that there have been few actual cases of underdetermination in the history of science. Usually the requirement of explaining the data is so exacting that scientists are lucky to find even one theory that fulfills it. Furthermore, if we take the underdetermination argument seriously, it implies that we can know about only what we have directly
observed. For example, we could not theorize that
dinosaurs once lived based on the
fossil evidence because other theories (e.g., that the fossils are clever hoaxes) can account for the same data.
Incompatible models argument According to the incompatible models argument, in certain cases the existence of diverse models for a single phenomenon can be taken as evidence of anti-realism. One example is due to
Margaret Morrison, who worked to show that the
shell model and the
liquid-drop model give contradictory descriptions of the
atomic nucleus, even though both models are predictive. ==See also==