HOME

TheInfoList



OR:

Models of scientific inquiry have two functions: first, to provide a descriptive account of ''how'' scientific inquiry is carried out in practice, and second, to provide an explanatory account of ''why'' scientific inquiry succeeds as well as it appears to do in arriving at genuine knowledge. The philosopher Wesley C. Salmon described scientific inquiry:
The search for scientific knowledge ends far back into antiquity. At some point in the past, at least by the time of Aristotle, philosophers recognized that a fundamental distinction should be drawn between two kinds of scientific knowledge—roughly, knowledge ''that'' and knowledge ''why''. It is one thing to know ''that'' each planet periodically reverses the direction of its motion with respect to the background of fixed stars; it is quite a different matter to know ''why''. Knowledge of the former type is descriptive; knowledge of the latter type is explanatory. It is explanatory knowledge that provides scientific understanding of the world. (Salmon, 2006, pg. 3)
According to the National Research Council (United States): "Scientific inquiry refers to the diverse ways in which scientists study the natural world and propose explanations based on the evidence derived from their work."


Accounts of scientific inquiry


Classical model

The classical model of scientific inquiry derives from
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
, who distinguished the forms of approximate and exact reasoning, set out the threefold scheme of
abductive Abductive reasoning (also called abduction,For example: abductive inference, or retroduction) is a form of logical inference formulated and advanced by American philosopher Charles Sanders Peirce beginning in the last third of the 19th centu ...
,
deductive Deductive reasoning is the mental process of drawing deductive inferences. An inference is deductively valid if its conclusion follows logically from its premises, i.e. if it is impossible for the premises to be true and the conclusion to be fals ...
, and inductive inference, and also treated the compound forms such as reasoning by
analogy Analogy (from Greek ''analogia'', "proportion", from ''ana-'' "upon, according to" lso "against", "anew"+ ''logos'' "ratio" lso "word, speech, reckoning" is a cognitive process of transferring information or meaning from a particular subject ( ...
.


Pragmatic model


Logical empiricism

Wesley Salmon Wesley Charles Salmon (August 9, 1925 – April 22, 2001) was an American philosopher of science renowned for his work on the nature of scientific explanation. He also worked on confirmation theory, trying to explicate how probability theory vi ...
(1989) began his historical survey of scientific explanation with what he called the ''received view'', as it was received from Hempel and
Oppenheim Oppenheim () is a town in the Mainz-Bingen district of Rhineland-Palatinate, Germany. The town is a well-known wine center, being the home of the German Winegrowing Museum, and is particularly known for the wines from the Oppenheimer Krötenbru ...
in the years beginning with their ''Studies in the Logic of Explanation'' (1948) and culminating in Hempel's ''
Aspects of Scientific Explanation ''Aspects of Scientific Explanation and other Essays in the Philosophy of Science'' is a 1965 book by the philosopher Carl Gustav Hempel. It is regarded as one of the most important works in the philosophy of science written after World War II. R ...
'' (1965). Salmon summed up his analysis of these developments by means of the following Table. In this classification, a
deductive-nomological The deductive-nomological model (DN model) of scientific explanation, also known as Hempel's model, the Hempel– Oppenheim model, the Popper–Hempel model, or the covering law model, is a formal view of scientifically answering questions asking ...
(D-N) explanation of an occurrence is a valid deduction whose conclusion states that the outcome to be explained did in fact occur. The deductive argument is called an ''explanation'', its premisses are called the ''explanans'' ( L: ''explaining'') and the conclusion is called the ''explanandum'' ( L: ''to be explained''). Depending on a number of additional qualifications, an explanation may be ranked on a scale from ''potential'' to ''true''. Not all explanations in science are of the D-N type, however. An ''inductive-statistical'' (I-S) explanation accounts for an occurrence by subsuming it under statistical laws, rather than categorical or universal laws, and the mode of subsumption is itself inductive instead of deductive. The D-N type can be seen as a limiting case of the more general I-S type, the measure of certainty involved being complete, or
probability Probability is the branch of mathematics concerning numerical descriptions of how likely an Event (probability theory), event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and ...
1, in the former case, whereas it is less than complete, probability < 1, in the latter case. In this view, the D-N mode of reasoning, in addition to being used to explain particular occurrences, can also be used to explain general regularities, simply by deducing them from still more general laws. Finally, the ''deductive-statistical'' (D-S) type of explanation, properly regarded as a subclass of the D-N type, explains statistical regularities by deduction from more comprehensive statistical laws. (Salmon 1989, pp. 8–9). Such was the ''received view'' of scientific explanation from the point of view of
logical empiricism Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, is a movement in Western philosophy whose central thesis was the verification principle (also known as the verifiability criterion of ...
, that Salmon says "held sway" during the third quarter of the last century (Salmon, p. 10).


Choice of a theory

During the course of history, one theory has succeeded another, and some have suggested further work while others have seemed content just to explain the phenomena. The reasons why one theory has replaced another are not always obvious or simple. The philosophy of science includes the question: ''What criteria are satisfied by a 'good' theory''. This question has a long history, and many scientists, as well as philosophers, have considered it. The objective is to be able to choose one theory as preferable to another without introducing
cognitive bias A cognitive bias is a systematic pattern of deviation from norm or rationality in judgment. Individuals create their own "subjective reality" from their perception of the input. An individual's construction of reality, not the objective input, m ...
. Several often proposed criteria were summarized by Colyvan. A good theory: # contains few arbitrary elements (simplicity/parsimony); # agrees with and explains all existing observations (unificatory/
explanatory power Explanatory power is the ability of a hypothesis or theory to explain the subject matter effectively to which it pertains. Its opposite is ''explanatory impotence''. In the past, various criteria or measures for explanatory power have been prop ...
) and makes detailed predictions about future observations that can disprove or
falsify Falsifiability is a standard of evaluation of scientific theories and hypotheses that was introduced by the philosopher of science Karl Popper in his book ''The Logic of Scientific Discovery'' (1934). He proposed it as the cornerstone of a so ...
the theory if they are not borne out; # is fruitful, where the emphasis by Colyvan is not only upon prediction and falsification, but also upon a theory's seminality in suggesting future work; # is elegant (formal elegance; no ''ad hoc'' modifications). Stephen Hawking supported items 1, 2 and 4, but did not mention fruitfulness. On the other hand, Kuhn emphasizes the importance of seminality. The goal here is to make the choice between theories less arbitrary. Nonetheless, these criteria contain subjective elements, and are
heuristics A heuristic (; ), or heuristic technique, is any approach to problem solving or self-discovery that employs a practical method that is not guaranteed to be optimal, perfect, or rational, but is nevertheless sufficient for reaching an immediate, ...
rather than part of
scientific method The scientific method is an empirical method for acquiring knowledge that has characterized the development of science since at least the 17th century (with notable practitioners in previous centuries; see the article history of scientific m ...
. Also, criteria such as these do not necessarily decide between alternative theories. Quoting Bird: It also is debatable whether existing scientific theories satisfy all these criteria, which may represent goals not yet achieved. For example, explanatory power over all existing observations (criterion 3) is satisfied by no one theory at the moment. The
desiderata "Desiderata" (Latin: "things desired") is an early 1920s prose poem by the American writer Max Ehrmann. Although he copyrighted it in 1927, he distributed copies of it without a required copyright notice during 1933 and , thereby forfeiting his ...
of a "good" theory have been debated for centuries, going back perhaps even earlier than Occam's razor, which often is taken as an attribute of a good theory. Occam's razor might fall under the heading of "elegance", the first item on the list, but too zealous an application was cautioned by
Albert Einstein Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...
: "Everything should be made as simple as possible, but no simpler." It is arguable that ''parsimony'' and ''elegance'' "typically pull in different directions". The falsifiability item on the list is related to the criterion proposed by Popper as demarcating a scientific theory from a theory like astrology: both "explain" observations, but the scientific theory takes the risk of making predictions that decide whether it is right or wrong:
Thomas Kuhn Thomas Samuel Kuhn (; July 18, 1922 – June 17, 1996) was an American philosopher of science whose 1962 book ''The Structure of Scientific Revolutions'' was influential in both academic and popular circles, introducing the term '' paradigm ...
argued that changes in scientists' views of reality not only contain subjective elements, but result from group dynamics, "revolutions" in scientific practice which result in
paradigm shift A paradigm shift, a concept brought into the common lexicon by the American physicist and philosopher Thomas Kuhn, is a fundamental change in the basic concepts and experimental practices of a scientific discipline. Even though Kuhn restricted t ...
s. As an example, Kuhn suggested that the
heliocentric Heliocentrism (also known as the Heliocentric model) is the astronomical model in which the Earth and planets revolve around the Sun at the center of the universe. Historically, heliocentrism was opposed to geocentrism, which placed the Earth at ...
"
Copernican Revolution The Copernican Revolution was the paradigm shift from the Ptolemaic model of the heavens, which described the cosmos as having Earth stationary at the center of the universe, to the heliocentric model with the Sun at the center of the Solar Sys ...
" replaced the
geocentric In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most geocentric models, the Sun, Moon, stars, an ...
views of
Ptolemy Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
not because of empirical failures, but because of a new "paradigm" that exerted control over what scientists felt to be the more fruitful way to pursue their goals.


Aspects of scientific inquiry


Deduction and induction

Deductive reasoning Deductive reasoning is the mental process of drawing deductive inferences. An inference is deductively valid if its conclusion follows logically from its premises, i.e. if it is impossible for the premises to be true and the conclusion to be fals ...
and inductive reasoning are quite different in their approaches.


Deduction

Deductive reasoning is the reasoning of proof, or
logical implication Logical consequence (also entailment) is a fundamental concept in logic, which describes the relationship between statements that hold true when one statement logically ''follows from'' one or more statements. A valid logical argument is one ...
. It is the logic used in mathematics and other
axiomatic system In mathematics and logic, an axiomatic system is any set of axioms from which some or all axioms can be used in conjunction to logically derive theorems. A theory is a consistent, relatively-self-contained body of knowledge which usually contains ...
s such as formal logic. In a deductive system, there will be
axiom An axiom, postulate, or assumption is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments. The word comes from the Ancient Greek word (), meaning 'that which is thought worthy or f ...
s (postulates) which are not proven. Indeed, they cannot be proven without circularity. There will also be primitive terms which are not defined, as they cannot be defined without circularity. For example, one can define a line as a set of points, but to then define a point as the intersection of two lines would be circular. Because of these interesting characteristics of
formal system A formal system is an abstract structure used for inferring theorems from axioms according to a set of rules. These rules, which are used for carrying out the inference of theorems from axioms, are the logical calculus of the formal system. A form ...
s, Bertrand Russell humorously referred to mathematics as "the field where we don't know what we are talking about, nor whether or not what we say is true". All theorems and corollaries are proven by exploring the implications of the axiomata and other theorems that have previously been developed. New terms are defined using the primitive terms and other derived definitions based on those primitive terms. In a deductive system, one can correctly use the term "proof", as applying to a theorem. To say that a theorem is proven means that it is impossible for the axioms to be true and the theorem to be false. For example, we could do a simple syllogism such as the following: #
Arches National Park Arches National Park is a national park in eastern Utah, United States. The park is adjacent to the Colorado River, north of Moab, Utah. More than 2,000 natural sandstone arches are located in the park, including the well-known Delicate Arch, ...
lies within the state of
Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
. # I am standing in Arches National Park. # Therefore, I am standing in the state of Utah. Notice that it is not possible (assuming all of the trivial qualifying criteria are supplied) to be in Arches and not be in Utah. However, one can be in Utah while not in Arches National Park. The implication only works in one direction. Statements (1) and (2) taken together imply statement (3). Statement (3) does not imply anything about statements (1) or (2). Notice that we have not proven statement (3), but we have shown that statements (1) and (2) together imply statement (3). In mathematics, what is proven is not the truth of a particular theorem, but that the axioms of the system imply the theorem. In other words, it is impossible for the axioms to be true and the theorem to be false. The strength of deductive systems is that they are sure of their results. The weakness is that they are abstract constructs which are, unfortunately, one step removed from the physical world. They are very useful, however, as mathematics has provided great insights into natural science by providing useful models of natural phenomena. One result is the development of products and processes that benefit mankind.


Induction


= Inductive generalization

= Learning about the physical world often involves the use of inductive reasoning. It is useful in enterprises as science and crime scene detective work. One makes a set of specific observations, and seeks to make a general principle based on those observations, which will point to certain other observations that would naturally result from either a repeat of the experiment or making more observations from a slightly different set of circumstances. If the predicted observations hold true, one may be on the right track. However, the general principle has not been proven. The principle implies that certain observations should follow, but positive observations do not imply the principle. It is quite possible that some other principle could also account for the known observations, and may do better with future experiments. The implication flows in only one direction, as in the syllogism used in the discussion on deduction. Therefore, it is never correct to say that a scientific principle or hypothesis/theory has been "proven" in the rigorous sense of proof used in deductive systems. A classic example of this is the study of gravitation. Newton formed a law for gravitation stating that the force of gravitation is directly proportional to the product of the two masses and inversely proportional to the square of the distance between them. For over 170 years, all observations seemed to validate his equation. However, telescopes eventually became powerful enough to see a slight discrepancy in the orbit of Mercury. Scientists tried everything imaginable to explain the discrepancy, but they could not do so using the objects that would bear on the orbit of Mercury. Eventually, Einstein developed his theory of
general relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...
and it explained the orbit of Mercury and all other known observations dealing with gravitation. During the long period of time when scientists were making observations that seemed to validate Newton's theory, they did not, in fact, prove his theory to be true. However, it must have seemed at the time that they did. It only took one counterexample (Mercury's orbit) to prove that there was something wrong with his theory. This is typical of inductive reasoning. All of the observations that seem to validate the theory, do not prove its truth. But one counter-example can prove it false. That means that deductive logic is used in the evaluation of a theory. In other words, if A implies B, then not B implies not A. Einstein's theory of General Relativity has been supported by many observations using the best scientific instruments and experiments. However, his theory now has the same status as Newton's theory of gravitation prior to seeing the problems in the orbit of Mercury. It is highly credible and validated with all we know, but it is not proven. It is only the best we have at this point in time. Another example of correct scientific reasoning is shown in the current search for the Higgs boson. Scientists on the
Compact Muon Solenoid The Compact Muon Solenoid (CMS) experiment is one of two large general-purpose particle physics detectors built on the Large Hadron Collider (LHC) at CERN in Switzerland and France. The goal of the CMS experiment is to investigate a wide range ...
experiment at the Large Hadron Collider have conducted experiments yielding data suggesting the existence of the Higgs boson. However, realizing that the results could possibly be explained as a background fluctuation and not the Higgs boson, they are cautious and waiting for further data from future experiments. Said Guido Tonelli: One way of describing
scientific method The scientific method is an empirical method for acquiring knowledge that has characterized the development of science since at least the 17th century (with notable practitioners in previous centuries; see the article history of scientific m ...
would then contain these steps as a minimum: # Make a set of observations regarding the phenomenon being studied. # Form a hypothesis that might explain the observations. (This may involve inductive and/or
abductive reasoning Abductive reasoning (also called abduction,For example: abductive inference, or retroduction) is a form of logical inference formulated and advanced by American philosopher Charles Sanders Peirce beginning in the last third of the 19th century ...
.) # Identify the implications and outcomes that must follow, if the hypothesis is to be true. # Perform other experiments or observations to see if any of the predicted outcomes fail. # If any predicted outcomes fail, the hypothesis is proven false since if A implies B, then not B implies not A (by deduction). It is then necessary to change the hypothesis and go back to step 3. If the predicted outcomes are confirmed, the hypothesis is not proved, but rather can be said to be consistent with known data. When a hypothesis has survived a sufficient number of tests, it may be promoted to a
scientific theory A scientific theory is an explanation of an aspect of the natural world and universe that has been repeatedly tested and corroborated in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluatio ...
. A theory is a hypothesis that has survived many tests and seems to be consistent with other established scientific theories. Since a theory is a promoted hypothesis, it is of the same 'logical' species and shares the same logical limitations. Just as a hypothesis cannot be proven but can be disproved, that same is true for a theory. It is a difference of degree, not kind.


= Argument from analogy

= Arguments from analogy are another type of inductive reasoning. In arguing from analogy, one infers that since two things are alike in several respects, they are likely to be alike in another respect. This is, of course, an assumption. It is natural to attempt to find similarities between two phenomena and wonder what one can learn from those similarities. However, to notice that two things share attributes in several respects does not imply any similarities in other respects. It is possible that the observer has already noticed all of the attributes that are shared and any other attributes will be distinct. Argument from analogy is an unreliable method of reasoning that can lead to erroneous conclusions, and thus cannot be used to establish scientific facts.


See also

*
Deductive-nomological The deductive-nomological model (DN model) of scientific explanation, also known as Hempel's model, the Hempel– Oppenheim model, the Popper–Hempel model, or the covering law model, is a formal view of scientifically answering questions asking ...
*
Explanandum and explanans An explanandum (a Latin term) is a sentence describing a phenomenon that is to be explained, and the explanans are the sentences adduced as explanations of that phenomenon. For example, one person may pose an ''explanandum'' by asking "Why is there ...
*
Hypothetico-deductive method The hypothetico-deductive model or method is a proposed description of the scientific method. According to it, scientific inquiry proceeds by formulating a hypothesis in a form that can be falsifiable, using a test on observable data where the ou ...
* Inquiry


References


Further reading

* ''An Introduction to Logic and Scientific Method'' (1934) by
Ernest Nagel Ernest Nagel (November 16, 1901 – September 20, 1985) was an American philosopher of science. Suppes, Patrick (1999)Biographical memoir of Ernest Nagel In '' American National Biograph''y (Vol. 16, pp. 216-218). New York: Oxford University Pr ...
and
Morris Raphael Cohen Morris Raphael Cohen ( be, Мо́рыс Рафаэ́ль Ко́эн; July 25, 1880 – January 28, 1947) was an American philosopher, lawyer, and legal scholar who united pragmatism with logical positivism and linguistic analysis. This union co ...
* ''Dictionary of Philosophy'' (1942) by
Dagobert D. Runes Dagobert David Runes (January 6, 1902 – September 24, 1982) was a philosopher and author. Biography Born in Zastavna, Bukovina, Austro-Hungary (now in Ukraine), Runes emigrated to the United States in 1926. He had received a doctorat ...

Understanding Scientific Progress: Aim-Oriented Empiricism
2017, Paragon House, St. Paul by Nicholas Maxwell


External links


Precession of the perihelion of Mercury
{{DEFAULTSORT:Models Of Scientific Inquiry Conceptual modelling Philosophy of science Inquiry