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Scientific method


 
 
Scientific method refers to the body of techniqueTechnique Summary

A technique is a way of efficiently accomplishing a task in a manner that is not immediately obvious or straightforward....
s for investigating phenomenaPhenomenon

A phenomenon is an observable event, particularly something special ....
, acquiring new knowledgeKnowledge

Knowledge is what is known. Like the related concepts truth, belief and wisdom....
, or correcting and integrating previous knowledge. It is based on gathering observableObservable

In physics, particularly in quantum physics, a system observable is a property of the system state that can be determined by...
, empiricalEmpirical

A central concept in science and the scientific method is that all evidence must be empirical, or empirically based, t...
 and measurableMeasure

Measure can mean:* Measurement, the process of estimating an object's magnitude relative to some unit of measurement...
 evidenceEvidence

Evidence in its broadest sense, refers to anything that is used to determine or demonstrate the truth of an assertion....
 subject to specific principles of reasoningReasoning Summary

Reasoning is defined very differently depending on the context of the understanding of reason as a form of knowledge....
. A scientific method consists of the collection of data through observationObservation

Observation is an activity of a sapient or sentient living being, which senses and assimiliates the knowledge of a phenomeno...
 and experimentExperiment

In the scientific method, an experiment , is a set of actions and observations, performed in the context of solving a partic...
ation, and the formulation and testing of hypothesesHypothesis

A hypothesi is a suggested explanation of a phenomenon or reasoned proposal suggesting a possible correlation between multi...
.

Although procedures vary from one field of inquiryFields of science

Fields of science are widely-recognized categories of specialized expertise within science, and typically embody their own t...
 to another, identifiable features distinguish scientific inquiry from other methodologies of knowledge. Scientific researchers propose hypothesesHypothesis

A hypothesi is a suggested explanation of a phenomenon or reasoned proposal suggesting a possible correlation between multi...
 as explanations of phenomena, and design experimentExperiment

In the scientific method, an experiment , is a set of actions and observations, performed in the context of solving a partic...
al studiesResearch

Research is often described as an active, diligent, and systematic process of inquiry aimed at discovering, interpreting, an...
 to test these hypotheses. These steps must be repeatable in order to dependably predict any future results. TheoriesTheory

The word theory has a number of distinct meanings in different fields of knowledge, depending on their methodologies and...
 that encompass wider domains of inquiry may bind many hypotheses together in a coherent structure.






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Scientific method refers to the body of techniqueTechnique Summary

A technique is a way of efficiently accomplishing a task in a manner that is not immediately obvious or straightforward....
s for investigating phenomenaPhenomenon

A phenomenon is an observable event, particularly something special ....
, acquiring new knowledgeKnowledge

Knowledge is what is known. Like the related concepts truth, belief and wisdom....
, or correcting and integrating previous knowledge. It is based on gathering observableObservable

In physics, particularly in quantum physics, a system observable is a property of the system state that can be determined by...
, empiricalEmpirical

A central concept in science and the scientific method is that all evidence must be empirical, or empirically based, t...
 and measurableMeasure

Measure can mean:* Measurement, the process of estimating an object's magnitude relative to some unit of measurement...
 evidenceEvidence

Evidence in its broadest sense, refers to anything that is used to determine or demonstrate the truth of an assertion....
 subject to specific principles of reasoningReasoning Summary

Reasoning is defined very differently depending on the context of the understanding of reason as a form of knowledge....
. A scientific method consists of the collection of data through observationObservation

Observation is an activity of a sapient or sentient living being, which senses and assimiliates the knowledge of a phenomeno...
 and experimentExperiment

In the scientific method, an experiment , is a set of actions and observations, performed in the context of solving a partic...
ation, and the formulation and testing of hypothesesHypothesis

A hypothesi is a suggested explanation of a phenomenon or reasoned proposal suggesting a possible correlation between multi...
.

Although procedures vary from one field of inquiryFields of science

Fields of science are widely-recognized categories of specialized expertise within science, and typically embody their own t...
 to another, identifiable features distinguish scientific inquiry from other methodologies of knowledge. Scientific researchers propose hypothesesHypothesis

A hypothesi is a suggested explanation of a phenomenon or reasoned proposal suggesting a possible correlation between multi...
 as explanations of phenomena, and design experimentExperiment

In the scientific method, an experiment , is a set of actions and observations, performed in the context of solving a partic...
al studiesResearch

Research is often described as an active, diligent, and systematic process of inquiry aimed at discovering, interpreting, an...
 to test these hypotheses. These steps must be repeatable in order to dependably predict any future results. TheoriesTheory

The word theory has a number of distinct meanings in different fields of knowledge, depending on their methodologies and...
 that encompass wider domains of inquiry may bind many hypotheses together in a coherent structure. This in turn may help form new hypotheses or place groups of hypotheses into context.

Among other facets shared by the various fields of inquiry is the conviction that the process be objectiveObjectivity (science)

In science, the ideal of objectivity is an essential aspect of the scientific method, and is generally considered by the sci...
 to reduce a biasBias

A bias is a prejudice in a general or specific sense, usually in the sense for having a preference to one particular point o...
ed interpretation of the results. Another basic expectation is to document, archiveFacts About Scientific data archiving

Scientific data archiving refers to the long-term storage of scientific data and methods....
 and share all data and methodologyMethodology

Methodology is defined as "a body of methods, rules, and postulates employed by a discipline", "a particular procedure o...
 so they are available for careful scrutiny by other scientists, thereby allowing other researchers the opportunity to verify results by attempting to reproduceReproducibility

Reproducibility is one of the main principles of the scientific method, and refers to the ability of a test or experiment to...
 them. This practice, called full disclosure, also allows statistical measures of the reliabilityReliability (statistics)

In statistics, reliability is the consistency of a set of measurements or measuring instrument....
 of these data to be established.

Introduction to scientific method



Since Ibn al-Haytham (Alhazen, 965–1039), a pioneer of scientific methodHistory of scientific method

The history of scientific method is inseparable from the history of science itself. ...
, the emphasis has been on seeking truthTruth

Common dictionary definitions of truth mention some form of accord with fact or reality....
:



The conjecture that "Light travels through transparent bodies in straight lines only", was corroborated by Alhazen only after years of effort. His demonstration of the conjecture was to place a straight stick or a taut thread next to the light beam, to prove that light travels in a straight line.

Scientific methodology has been practiced in some form for at least one thousand years. There are difficulties in a formulaic statement of method, however. As William Whewell (1794–1866) noted in his History of Inductive Science (1837) and in Philosophy of Inductive Science (1840), "invention, sagacity, genius" are required at every step in scientific methodWilliam Whewell

William Whewell was an English polymath, scientist, Anglican priest, philosopher, theologian and historian of science....
. It is not enough to base scientific method on experienceEmpiricism

In philosophy generally, empiricism is a theory of knowledge emphasizing the role of experience....
 alone; multiple steps are needed in scientific method, ranging from our experience to our imagination, back and forth.

In the twentieth century, a hypothetico-deductive model for scientific methodFacts About Hypothetico-deductive model

The hypothetico-deductive model is a theory about scientific method....
 was formulated (for a more formal discussion, see belowScientific method Summary

Scientific method is a body of techniques for investigating phenomena and acquiring new knowledge, as well as for correcting...
):
1. Use your experience: Consider the problem and try to make sense of it. Look for previous explanations. If this is a new problem to you, then move to step 2.
2. Form a conjecture: When nothing else is yet known, try to state an explanation, to someone else, or to your notebook.
3. Deduce a prediction from that explanation: If you assume 2 is true, what consequences follow?
4. Test : Look for the opposite of each consequence in order to disprove 2. It is a logical error to seek 3 directly as proof of 2. This error is called affirming the consequentAffirming the consequent

Affirming the consequent is a logical fallacy in the form of a hypothetical proposition....
.


This model underlies the scientific revolutionScientific revolution

The event which most historians of science call the scientific revolution can be dated roughly as having begun in 1543, the ...
. One thousand years ago, Alhazen demonstrated the importance of steps 1 and 4. Galileo (1638) also showed the importance of step 4 (also called ExperimentExperiment

In the scientific method, an experiment , is a set of actions and observations, performed in the context of solving a partic...
) in Two New SciencesTwo New Sciences

The Discourses and Mathematical Demonstrations Relating to Two New Sciences was Galileo's final book and a sort of scien...
. One possible sequence in this model would be 1, 2, 3, 4. If the outcome of 4 holds, and 3 is not yet disproven, you may continue with 3, 4, 1, and so forth; but if the outcome of 4 shows 3 to be false, you will have go back to 2 and try to invent a new 2, deduce a new 3, look for 4, and so forth.

Note that this method can never absolutely verify (prove the truth of) 2. It can only falsify 2. (This is what Einstein meant when he said "No amount of experimentation can ever prove me right; a single experiment can prove me wrong.Falsifiability

In science and the philosophy of science, falsifiability, contingency, and defeasibility are roughly...
")

In the twentieth century, Ludwik FleckLudwik Fleck Summary

Ludwik Fleck was a Polish medical doctor and biologist who developed in the 1930s the concept of thought collectives....
 (1896–1961) and others found that we need to consider our experiences more carefully, because our experience may be biased, and that we need to be more exact when describing our experiences. These considerations are discussed below.


Truth and belief


Belief can alter observations; those with a particular belief will often see things as reinforcing their belief, even if they do not. Needham'sJoseph Needham

Joseph Terence Montgomery Needham was a British biochemist, but was best known as a pre-eminent authority on the history of ...
 Science and Civilization in China uses the 'flying horse' image as an example of observation: in it, a horse's legs are depicted as splayed, when the stop-action picture by Eadweard MuybridgeEadweard Muybridge Overview

Eadweard Muybridge was a British-born photographer, known primarily for his early use of multiple cameras to capture motion...
 shows otherwise. Note that at the moment that no hoof is touching the ground, the horse's legs are gathered together and are not splayed.
Earlier paintings depict the incorrect flying horse observation. This demonstrates Ludwik FleckLudwik Fleck Summary

Ludwik Fleck was a Polish medical doctor and biologist who developed in the 1930s the concept of thought collectives....
's caution that people observe what they expect to observe, until shown otherwise; our beliefs will affect our observations (and therefore our subsequent actions). The purpose of the scientific method is to test a hypothesis, a belief about how things are, via repeatable experimental observations which can contradict the hypothesis so as to fight this observer bias.

Elements of scientific method


There are many ways of outlining the basic method shared by all fields of scientific inquiry. The following examples are typical classifications of the most important components of the method on which there is wide agreement in the scientific communityScientific community

The scientific community consists of the total body of scientists, its relationships and interactions....
 and among philosophers of sciencePhilosophy of science

Philosophy of science is the branch of philosophy that studies the philosophical assumptions, foundations, and implications ...
. There are, however, disagreements about some aspects.

The following set of methodological elements and organization of procedures tends to be more characteristic of natural sciences than social sciences. In the social sciences mathematical and statistical methods of verification and hypotheses testing may be less stringent. Nonetheless the cycle of hypothesis, verification and formulation of new hypotheses will resemble the cycle described below.

Each element of a scientific method is subject to peer reviewPeer review

Peer review is a process of subjecting an author's scholarly work or ideas to the scrutiny of others who are experts in the...
 for possible mistakes. These activities do not describe all that scientists do but apply mostly to experimental sciences (e.g., physics, chemistry). The elements above are often taught in the educational systemEducation

Education is the process by which an individual is encouraged and enabled to develop fully his or her innate potential; it m...
.

Scientific method is not a recipe: it requires intelligence, imagination, and creativity. It is also an ongoing cycle, constantly developing more useful, accurate and comprehensive models and methods. For example, when Einstein developed the Special and General Theories of Relativity, he did not in any way refute or discount Newton's Principia. On the contrary, if the astronomically large, the vanishingly small, and the extremely fast are reduced out from Einstein's theories — all phenomena that Newton could not have observed — Newton's equations remain. Einstein's theories are expansions and refinements of Newton's theories, and observations that increase our confidence in them also increase our confidence in Newton's approximations to them.

A linearized, pragmatic scheme of the four points above is sometimes offered as a guideline for proceeding:

The iterative cycle inherent in this step-by-step methodology goes from point 3 to 6 back to 3 again.

While this schema outlines a typical hypothesis/testing method, it should also be noted that a number of philosophers, historians and sociologists of science (perhaps most notably Paul FeyerabendPaul Feyerabend

Paul Karl Feyerabend was an Austrian-born philosopher of science who lived in England, the United States, New Zealand, Ital...
) claim that such descriptions of scientific method have little relation to the ways science is actually practiced.

The "operational" model combines the concepts of factory-style processProcess

Process is a naturally occurring or designed sequence of changes of properties/attributes of a system/object....
ing, operational definitionOperational definition

An operational definition is a description of something—such as a variable, term, or object—in terms of the spe...
, and utilityUtility Overview

In economics, utility is a measure of the happiness or satisfaction gained consuming commodities ....
:

The Keystones of Science project, sponsored by the journal ScienceScience (journal)

Science is the academic journal of the American Association for the Advancement of Science and is considered one of the ...
, has selected a number of scientific articles from that journal and annotated them, illustrating how different parts of each article embody scientific method. is an annotated example of this scientific method example titled Microbial Genes in the Human GenomeHuman genome

The human genome is the genome of Homo sapiens, which is composed of 24 distinct chromosomes with a total of approximate...
: Lateral Transfer or Gene Loss?
.

DNA example


Each element of scientific method is illustrated below by an example from the discovery of the structure of DNADNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions for the biological development of a cellu...
:
  • DNA-characterizations: in this case, although the significance of the gene had been established, the mechanism was unclear to anyone, as of 1950.
  • DNA-hypotheses: Crick and Watson hypothesized that the gene had a physical basis - it was helical.
  • DNA-predictions: from earlier work on tobacco mosaic virusTobacco mosaic virus

    The Tobacco mosaic virus is an RNA virus that infects plants, especially tobacco and other members of the family Solanaceae,...
    , Watson was aware of the significance of Crick's formulation of the transform of a helix. Thus he was primed for the significance of the X-shape in photo 51.
  • DNA-experiments: Watson sees photo 51Photo 51

    Photo 51 is the name given to an X-ray diffraction image of DNA taken by Rosalind Franklin in 1952 that was critical evidenc...
    .


The examples are continued in "Evaluations and iterations" with DNA-iterations.

Characterizations


Scientific method depends upon increasingly more sophisticated characterizations of the subjects of investigation. (The subjects can also be called or the unknowns.) For example, Benjamin FranklinBenjamin Franklin

Buffalo is an American city in western New York State....
 correctly characterized St. Elmo's fireSt. Elmo's fire

St. Elmo's fire is an electro-luminescent corona discharge caused by the ionization of the air during thunderstorms inside o...
 as electrical in natureNature

Nature, in the broadest sense, is equivalent to the natural world, 'physical universe, 'material world or ...
, but it has taken a long series of experiments and theory to establish this. While seeking the pertinent properties of the subjects, this careful thought may also entail some definitions and observations; the observations often demand careful measurements and/or counting.
  • "I am not accustomed to saying anything with certainty after only one or two observations." —Andreas Vesalius (1546)


The systematic, careful collection of measurements or counts of relevant quantities is often the critical difference between pseudo-sciences, such as alchemy, and a science, such as chemistry or biology. Scientific measurements taken are usually tabulated, graphed, or mapped, and statistical manipulations, such as correlationCorrelation

In probability theory and statistics, correlation, also called correlation coefficient, indicates the strength and dir...
 and regressionRegression

Generally, regression is a move backwards; It is the opposite of progression....
, performed on them. The measurements might be made in a controlled setting, such as a laboratory, or made on more or less inaccessible or unmanipulatable objects such as stars or human populations. The measurements often require specialized scientific instruments such as thermometers, spectroscopes, or voltmeters, and the progress of a scientific field is usually intimately tied to their invention and development.
Uncertainty

Measurements in scientific work are also usually accompanied by estimates of their uncertaintyUncertainty

Uncertainty is a term used in subtly different ways in a number of fields, including philosophy, statistics, economics, fina...
. The uncertainty is often estimated by making repeated measurements of the desired quantity. Uncertainties may also be calculated by consideration of the uncertainties of the individual underlying quantities that are used. Counts of things, such as the number of people in a nation at a particular time, may also have an uncertainty due to limitations of the method used. Counts may only represent a sample of desired quantities, with an uncertainty that depends upon the sampling method used and the number of samples taken.
Definition

Measurements demand the use of operational definitionOperational definition

An operational definition is a description of something—such as a variable, term, or object—in terms of the spe...
s
of relevant quantities. That is, a scientific quantity is described or defined by how it is measured, as opposed to some more vague, inexact or "idealized" definition. For example, electrical current, measured in amperes, may be operationally defined in terms of the mass of silver deposited in a certain time on an electrode in an electrochemical device that is described in some detail. The operational definition of a thing often relies on comparisons with standards: the operational definition of "mass" ultimately relies on the use of an artifact, such as a certain kilogram of platinum-iridium kept in a laboratory in France.

The scientific definition of a term sometimes differs substantially from its natural languageFacts About Natural language

The term natural language is used to distinguish languages spoken and signed by humans for general-purpose communication fr...
 usage. For example, massMass

Mass is a property of a physical object that quantifies the amount of matter and energy it is equivalent to....
 and weightWeight

Weight is a term of measurement referring to either an object's mass or to the gravitational force acting on the object....
 overlap in meaning in common discourse, but have distinct meanings in mechanicsMechanics

Mechanics is the branch of physics concerned with the behaviour of physical bodies when subjected to forces or displacement...
. Scientific quantities are often characterized by their units of measureUnits of measurement

The definition, agreement and practical use of units of measurement have played a crucial role in human endeavour from early...
 which can later be described in terms of conventional physical units when communicating the work.

New theories sometimes arise upon realizing that certain terms had not previously been sufficiently clearly defined. For example, Albert Einstein'sAlbert Einstein

Albert Einstein was a German-born theoretical physicist....
 first paper on relativitySpecial relativity

The special theory of relativity was proposed in 1905 by Albert Einstein in his article "On the Electrodynamics of Moving Bo...
 begins by defining simultaneityRelativity of simultaneity

The relativity of simultaneity is the dependence of the notion of simultaneity on the observer....
 and the means for determining lengthLength

Length is the long dimension of any object....
. These ideas were skipped over by Isaac NewtonIsaac Newton

[[[Old Style and New Style dates|OS]]: [[25 December]] [[1642]] [[20 March]] [[1727]]] was an [[England|English]] [[physics|physicist,]]...
 with, "I do not define timeTime in physics

In physics, the treatment of time is a central issue....
, space, place and motionMotion (physics)

In physics, motion means a continuous change in the position of a body relative to a reference point, as measured by a parti...
, as being well known to all.
" Einstein's paper then demonstrates that they (viz., absolute time and length independent of motion) were approximations. Francis CrickFrancis Crick

[[ was an [[England|English]] [[physics|physicist]], [[molecular biology|molecular biologist]] and [[neuroscience|neuroscientist]],...
 cautions us that when characterizing a subject, however, it can be premature to define something when it remains ill-understood. In Crick's study of consciousnessConsciousness

Consciousness is a quality of the mind generally regarded to comprise qualities such as subjectivity, self-awareness, sentie...
, he actually found it easier to study awarenessAwareness

In biological psychology, awareness describes a human or animal's perception and cognitive reaction to a condition or event....
 in the visual systemVisual system Overview

The visual system is the part of the nervous system which allows organisms to see....
, rather than to study free willFree will

The problem of free will is the problem of whether human beings exercise control over their own actions and decisions....
, for example. His cautionary example was the gene; the gene was much more poorly understood before Watson and Crick's pioneering discovery of the structure of DNA; it would have been counterproductive to spend much time on the definition of the gene, before them.
Example of Characterizations

DNA-characterizations
The historyDNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions for the biological development of a cellu...
 of the discovery of the structure of DNA is a classic example of the elements of scientific method: in 1950 it was known that genetic inheritance had a mathematical description, starting with the studies of Gregor MendelGregor Mendel

Gregor Johann Mendel was an Augustinian abbot who is often called the "father of genetics" for his study of the inheritance...
. But the mechanism of the gene was unclear. Researchers in Bragg'sWilliam Lawrence Bragg

Sir William Lawrence Bragg CH, FRS, was a Australian physicist who won the Nobel Prize in Physics in 1915....
 laboratory at Cambridge UniversityUniversity of Cambridge Overview

name = University of Cambridge|latin_name = Universitas Cantabrigiensis...
 made X-rayX-ray

X-rays are a form of electromagnetic radiation with a wavelength in the range of 10 to 0.01 nanometres, corresponding to fre...
 diffractionDiffraction

Diffraction refers to the various phenomena associated with wave propagation, such as the bending, spreading and interferenc...
 pictures of various moleculeFacts About Molecule

In chemistry, a molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds....
s, starting with crystalCrystal

In chemistry and mineralogy, a crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regular...
s of saltSalt

In chemistry, a salt is any ionic compound composed of cations and anions so that the product is neutral ....
, and proceeding to more complicated substances. Using clues which were painstakingly assembled over the course of decades, beginning with its chemical composition, it was determined that it should be possible to characterize the physical structure of DNA, and the X-ray images would be the vehicle. ..2. DNA-hypothesesScientific method

Scientific method is a body of techniques for investigating phenomena and acquiring new knowledge, as well as for correcting...

Precession of Mercury


The characterization element can require extended and extensive study, even centuries. It took thousands of years of measurements, from the ChaldeaChaldea Overview

Chaldea, "the Chaldees" of the KJV Old Testament, was a Hellenistic designation for a part of Babylonia....
n, IndiaIndia

India , officially the Republic of India, is a country in South Asia....
n, PersiaPersian Empire

The Persian Empire was a series of historical empires that ruled over the Iranian plateau and beyond....
n, GreekGreece

GreeceGreece lies at the juncture of Europe, Asia, and Africa....
, ArabArab

The Arabs are predominantly speakers of the Arabic language, rather than a pure ethnic group, mainly found throughout the ...
ic and EuropeanEuropean ethnic groups

The European peoples are the various nations and ethnic groups of Europe....
 astronomers, to record the motion of planet EarthEarth

Earth is the third planet in the solar system in terms of distance from the Sun, and the fifth largest....
. Newton was able to condense these measurements into consequences of his laws of motionLaws of motion

In physics, a number of noted theories of the motion of objects have developed....
. But the perihelion of the planet MercuryMercury (planet)

Mercury is the nearest planet to the sun, orbiting at an average distance of about 58 million kilometers....
's orbitORBit Overview

ORBit is a CORBA compliant Object Request Broker....
 exhibits a precession that is not fully explained by Newton's laws of motion. The observed difference for Mercury's precessionPrecession

Precession refers to a change in the direction of the axis of a rotating object....
 between Newtonian theory and relativistic theory (approximately 43 arc-seconds per century), was one of the things that occurred to Einstein as a possible early test of his theory of General RelativityGeneral relativity Summary

General relativity is the geometrical theory of gravitation published by Albert Einstein in 1915....
.

Hypothesis development


A hypothesisHypothesis

A hypothesi is a suggested explanation of a phenomenon or reasoned proposal suggesting a possible correlation between multi...
 is a suggested explanation of a phenomenon, or alternately a reasoned proposal suggesting a possible correlation between or among a set of phenomena.

Normally hypotheses have the form of a mathematical modelMathematical model

A mathematical model is an abstract model that uses mathematical language to describe the behaviour of a system....
. Sometimes, but not always, they can also be formulated as existential statementsExistential quantification

In predicate logic, an existential quantification is the predication of a property or relation to at least one member of the...
, stating that some particular instance of the phenomenon being studied has some characteristic and causal explanations, which have the general form of universal statementsFacts About Universal quantification

In predicate logic, universal quantification is an attempt to formalise the notion that something is true for everything...
, stating that every instance of the phenomenon has a particular characteristic.

Scientists are free to use whatever resources they have — their own creativity, ideas from other fields, induction, Bayesian inferenceBayesian inference Summary

Bayesian inference is statistical inference in which evidence or observations are used to update or to newly infer the proba...
, and so on — to imagine possible explanations for a phenomenon under study. Charles Sanders Peirce, borrowing a page from AristotleAristotle

Aristotle was an ancient Greek philosopher, a student of Plato and teacher of Alexander the Great....
 (Prior AnalyticsPrior Analytics

Prior Analytics is Aristotle's work on deductive reasoning, part of his Organon, the instrument or manual of log...
, 2.25Inquiry

Inquiry is any proceeding or process that has the aim of augmenting knowledge, resolving doubt, or solving a problem....
) described the incipient stages of inquiryInquiry

Inquiry is any proceeding or process that has the aim of augmenting knowledge, resolving doubt, or solving a problem....
, instigated by the "irritation of doubt" to venture a plausible guess, as abductive reasoningInquiry

Inquiry is any proceeding or process that has the aim of augmenting knowledge, resolving doubt, or solving a problem....
. The history of science is filled with stories of scientists claiming a "flash of inspiration", or a hunch, which then motivated them to look for evidence to support or refute their idea. Michael PolanyiMichael Polanyi

Michael Polanyi was a HungarianBritish polymath whose thought and work extended across physical chemistry, economics, and ...
 made such creativity the centerpiece of his discussion of methodology.

William GlenWilliam Glen (geologist and historian)

William Glen is a geologist and historian....
 observes that

the success of a hypothesis, or its service to science, lies not simply in its perceived "truth", or power to displace, subsume or reduce a predecessor idea, but perhaps more in its ability to stimulate the research that will illuminate … bald suppositions and areas of vagueness.


In general scientists tend to look for theories that are "elegant" or "beautifulBeautiful

Beautiful can refer to:* Beauty, something that is aesthetically pleasing...
". In contrast to the usual English use of these terms, they here refer to a theory in accordance with the known facts, which is nevertheless relatively simple and easy to handle. Occam's RazorOccam's razor

Occam's razor is a principle attributed to the 14th-century English logician and Franciscan friar William of Ockham ....
 serves as a rule of thumb for making these determinations.
DNA-hypotheses
Linus PaulingLinus Pauling

Linus Carl Pauling was an American quantum chemist and biochemist, widely regarded as the premier chemist of the twentieth ...
 proposed that DNA was a triple helix. Francis CrickFrancis Crick

[[ was an [[England|English]] [[physics|physicist]], [[molecular biology|molecular biologist]] and [[neuroscience|neuroscientist]],...
 and James WatsonJames Watson

There is more than one person with the name James Watson:...
 learned of Pauling's hypothesis, understood from existing data that Pauling was wrong and realized that Pauling would soon realize his mistake. So the race was on to figure out the correct structure. Except that Pauling did not realize at the time that he was in a race! ..3. DNA-predictionsScientific method Summary

Scientific method is a body of techniques for investigating phenomena and acquiring new knowledge, as well as for correcting...

Predictions from the hypothesis


Any useful hypothesis will enable predictionPrediction

A prediction or forecast is a statement or claim that a particular event will occur in the future....
s, by reasoningReasoning

Reasoning is defined very differently depending on the context of the understanding of reason as a form of knowledge....
 including deductive reasoningDeductive reasoning

In traditional Aristotelian logic, Deductive reasoning is reasoning in which the conclusion is necessitated by, or reach...
. It might predict the outcome of an experiment in a laboratory setting or the observation of a phenomenon in nature. The prediction can also be statistical and only talk about probabilities.

It is essential that the outcome be currently unknown. Only in this case does the eventuation increase the probability that the hypothesis be true. If the outcome is already known, it's called a consequence and should have already been considered while formulating the hypothesisScientific method

Scientific method is a body of techniques for investigating phenomena and acquiring new knowledge, as well as for correcting...
.

If the predictions are not accessible by observation or experience, the hypothesis is not yet useful for the method, and must wait for others who might come afterward, and perhaps rekindle its line of reasoning. For example, a new technology or theory might make the necessary experiments feasible.
DNA-predictions
The hypothesis (by James WatsonJames Watson

There is more than one person with the name James Watson:...
 and Francis CrickFrancis Crick

[[ was an [[England|English]] [[physics|physicist]], [[molecular biology|molecular biologist]] and [[neuroscience|neuroscientist]],...
 among others) that DNA had a helical structure implied the prediction that it would produce an x shaped X-ray diffraction pattern. This followed from the work of Cochran, Crick and Vand (and independently by Stokes) who had provided a mathematical basis for the empirical observation that helical structures produce x shapes.

Also in their first paper, Watson and Crick predicted that the double helixDouble helix

In geometry a double helix typically consists of two congruent helices with the same axis, differing by a translation along ...
 structure that they discovered would prove important in biology, writing "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material". ..4. DNA-experimentsScientific method

Scientific method is a body of techniques for investigating phenomena and acquiring new knowledge, as well as for correcting...

General relativity



Einstein's theory of General RelativityGeneral relativity

General relativity is the geometrical theory of gravitation published by Albert Einstein in 1915....
 makes several specific predictions about the observable structure of space-time, such as a prediction that lightLight

Light is electromagnetic radiation with a wavelength that is visible to the eye or, in a technical or scientific context, e...
 bends in a gravitational fieldGravitational field

A gravitational field is a model used within physics to explain how gravity exists in the universe....
 and that the amount of bending depends in a precise way on the strength of that gravitational field. Arthur Eddington's observations made during a 1919 solar eclipseSolar eclipse

A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring Earth's view o...
 supported General Relativity rather than Newtonian gravitationGravitation

In physics, gravitation or gravity is the tendency of objects with mass to accelerate toward each other....
.

Experiments


Once predictions are made, they can be tested by experiments. If test results contradict predictions, then the hypotheses are called into question and explanations may be sought. Sometimes experiments are conducted incorrectly and are at fault. If the results confirm the predictions, then the hypotheses are considered likely to be correct but might still be wrong and are subject to further testing. The experimental controlExperimental control

Experimental controls are used in scientific experiments to prevent factors other than those being studied from affecting th...
 is a technique for dealing with observational error. This technique uses the contrast between multiple samples (or observations) under differing conditions, to see what varies or what remains the same. We vary the conditions for each measurement, to help isolate what has changed. Mill's canons can then help us figure out what the important factor is. Factor analysisFactor analysis

Factor analysis is a statistical technique used to explain variability among observed random variables in terms of fewer uno...
 is one technique for discovering the important factor in an effect.

Depending on the predictions, the experiments can have different shapes. It could be a classical experiment in a laboratory setting, a double-blindDouble-blind

The Double blind method is an important part of the scientific method, used to prevent research outcomes from being 'influen...
 study or an archaeological excavationExcavation

Excavation is the best-known and most commonly used technique within the science of archaeology....
. Even taking a plane from New YorkNew York

New York is a state in the northeastern United States....
 to ParisParis

native_name = Ville de Paris|common_name = Paris...
 is an experiment which tests the aerodynamicalAerodynamics

Aerodynamics is a branch of fluid dynamics concerned with the study of forces and gas flows....
 hypotheses used for constructing the plane.

Scientists assume an attitude of openness and accountability on the part of those conducting an experiment. Detailed record keeping is essential, to aid in recording and reporting on the experimental results, and providing evidence of the effectiveness and integrity of the procedure. They will also assist in reproducing the experimental results. Traces of this tradition can be seen in the work of HipparchusHipparchus

Hipparchus, the common Latinization of the Greek Hipparchos, can mean:...
 (190-120 BCE), when determining a value for the precession of the Earth, while controlled experimentsScientific control

A scientific control augments integrity in experiments by isolating variables as dictated by the scientific method in order ...
 can be seen in the works of Muslim scientistsIslamic science

Islamic science is science in the context of traditional religious ideas of Islam, including its ethics and philosophy....
 such as GeberGeber

Abu Musa Jabir ibn Hayyan , known also by his Latinised name Geber, was a prominent Islamic alchemist, pharmacist, ph...
 (721-815 CE), al-Battani (853–929) and Alhacen (965-1039).
DNA-experiments
Watson and Crick showed an initial (and incorrect) proposal for the structure of DNA to a team from Kings College - Rosalind FranklinRosalind Franklin

Rosalind Elsie Franklin was a British physical chemist and crystallographer who made important contributions to the understa...
, Maurice WilkinsMaurice Wilkins

Maurice Hugh Frederick Wilkins CBE FRS was a New Zealand-born British physicist and Nobel Laureate who contributed research ...
, and Raymond GoslingRaymond Gosling

Raymond Gosling is a distinguished scientist who worked with both Maurice Wilkins and Rosalind Franklin at King's College Lo...
. Franklin immediately spotted the flaws which concerned the water content. Later Watson saw Franklin's detailed X-ray diffraction imagesPhoto 51

Photo 51 is the name given to an X-ray diffraction image of DNA taken by Rosalind Franklin in 1952 that was critical evidenc...
 which showed an and confirmed that the structure was helical. This rekindled Watson and Crick's model building and led to the correct structure. ..1. DNA-characterizationsScientific method

Scientific method is a body of techniques for investigating phenomena and acquiring new knowledge, as well as for correcting...

Evaluation and iteration


Testing and improvement

The scientific process is iterative. At any stage it is possible that some consideration will lead the scientist to repeat an earlier part of the process. Failure to develop an interesting hypothesis may lead a scientist to re-define the subject they are considering. Failure of a hypothesis to produce interesting and testable predictions may lead to reconsideration of the hypothesis or of the definition of the subject. Failure of the experiment to produce interesting results may lead the scientist to reconsidering the experimental method, the hypothesis or the definition of the subject.

Other scientists may start their own research and enter the process at any stage. They might adopt the characterization and formulate their own hypothesis, or they might adopt the hypothesis and deduce their own predictions. Often the experiment is not done by the person who made the prediction and the characterization is based on experiments done by someone else. Published results of experiments can also serve as a hypothesis predicting their own reproducibility.
DNA-iterations
After considerable fruitless experimentation, being discouraged by their superior from continuing, and numerous false starts, Watson and Crick were able to infer the essential structure of DNADNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions for the biological development of a cellu...
 by concrete modelingModel (abstract)

An abstract model is a theoretical construct that represents something, with a set of variables and a set of logical and qua...
 of the physical shapesDNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions for the biological development of a cellu...
 of the nucleotideNucleotide

A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups....
s which comprise it. They were guided by the bond lengths which had been deduced by Linus PaulingLinus Pauling

Linus Carl Pauling was an American quantum chemist and biochemist, widely regarded as the premier chemist of the twentieth ...
 and by Rosalind FranklinRosalind Franklin

Rosalind Elsie Franklin was a British physical chemist and crystallographer who made important contributions to the understa...
's X-ray diffraction images. ..DNA ExampleScientific method

Scientific method is a body of techniques for investigating phenomena and acquiring new knowledge, as well as for correcting...

Confirmation

Science is a social enterprise, and scientific work tends to be accepted by the community when it has been confirmed. Crucially, experimental and theoretical results must be reproduced by others within the science community. Researchers have given their lives for this vision; Georg Wilhelm RichmannGeorg Wilhelm Richmann

Georg Wilhelm Richmann was a German physicist in Russia....
 was killed by ball lightningBall lightning

Ball lightning reportedly takes the form of a short-lived, glowing, floating object often the size and shape of a basketball...
 (1753) when attempting to replicate the 1752 kite-flying experiment of Benjamin FranklinBenjamin Franklin

Buffalo is an American city in western New York State....
.

To protect against bad science and fraudulent data, government research granting agencies like NSF and science journals like Nature and Science have a policy that researchers must archive their data and methods so other researchers can access it, test the data and methods and build on the research that has gone before. Scientific data archivingScientific data archiving

Scientific data archiving refers to the long-term storage of scientific data and methods....
 can be done at a number of national archives in the U.S. or in the World Data CenterWorld Data Center

The World Data Center system was created to archive and distribute data collected from the observational programs of the 195...
.

Models of scientific inquiry


Classical model

The classical model of scientific inquiry derives from Aristotle, who distinguished the forms of approximate and exact reasoning, set out the threefold scheme of abductiveFacts About Abductive reasoning

Abduction, or abductive reasoning, is the process of reasoning to the best explanations....
, deductiveDeductive reasoning Overview

In traditional Aristotelian logic, Deductive reasoning is reasoning in which the conclusion is necessitated by, or reach...
, and inductiveInductive reasoning

Induction or inductive reasoning, sometimes called inductive logic, is the process of reasoning in which the pre...
 inference, and also treated the compound forms such as reasoning by analogyAnalogy

Analogy is either the cognitive process of transferring information from a particular subject to another particular subject,...
.

Pragmatic model

Charles PeirceCharles Peirce

Charles Sanders Peirce, was an American polymath, born in Cambridge, Massachusetts....
 (1839-1914) considered scientific inquiry to be a species of the genus inquiry, which he defined as any means of fixing belief, that is, any means of arriving at a settled opinion on a matter in question. He observed that inquiry in general begins with a state of uncertainty and moves toward a state of certainty, sufficient at least to terminate the inquiry for the time being.

Peirce held that, in practical matters, slow and stumbling is not generally to be automatically preferred over instinct and tradition, and held that scientific method is best suited to theoretical inquiry. What recommends the specifically scientific method of inquiry above all others is the fact that it is deliberately designed to arrive, eventually, at the ultimately most secure beliefs, upon which the most successful actions can eventually be based. In 1877, he outlined four methods for the fixation of belief, the settlement of doubt, graded by their success in achieving a sound settlement of belief.

1. The method of tenacity -- persisting in that which one is inclined to think.

2. The method of authority -- conformity to a source of ready-made beliefs.

3. The method of congruity or the a priori or the dilettante or "what is agreeable to reason" -- leading to argumentation that gets finally nowhere.

4. The scientific method.

Peirce characterized scientific method in terms of the uses of inference, and paid special attention to the generation of explanations. As a question of presuppositions of reasoning, he defined truth as the correspondence of a sign (in particular, a proposition) to its object and, pragmatically, not as any actual consensus of any finite community (i.e., such that to inquire would be to go ask the experts for the answers), but instead as that ideal final opinion which all reasonable scientific intelligences would reach, sooner or later but still inevitably, if they pushed investigation far enough.In tandem he defined the real as a true sign's object (be that object a possibility or quality, or an actuality or brute fact, or a necessity or norm or law), which is what it is independently of any finite community's opinion and, pragmatically, has dependence only on the ideal final opinion. That is an opinion as far or near as the truth itself to you or me or any finite community of minds. Thus his theory of inquiry boils down to "do the science." He characterized the scientific method as follows:

1. Abduction (or retroduction). Generation of explanatory hypothesis. From abduction, Peirce distinguishes induction as inferring, on the basis of tests, the proportion of truth in the hypothesis. Every inquiry, whether into ideas, brute facts, or norms and laws, arises as a result of surprising observations in the given realm or realms, and the pondering of the phenomenon in all its aspects in the attempt to resolve the wonder. All explanatory content of theories is reached by way of abduction, the most insecure among modes of inference. Induction as a process is far too slow for that job, so economy of research demands abduction, whose modicum of success depends on one's being somehow attuned to nature, by dispositions learned and, some of them, likely inborn. Abduction has general justification inductively in that it works often enough and that nothing else works, at least not quickly enough when science is already properly rather slow, the work of indefinitely many generations. Peirce calls his pragmatism "the logic of abduction". His Pragmatic MaximPragmatic maxim

The pragmatic maxim, also known as the maxim of pragmatism or the maxim of pragmaticism, is a maxim of logic for...
 is: "Consider what effects that might conceivably have practical bearings you conceive the objects of your conception to have. Then, your conception of those effects is the whole of your conception of the object". His pragmatism is a method of sorting out conceptual confusions by equating the meaning of any concept with the conceivable practical consequences of whatever it is which the concept portrays. It is a method of experimentational mental reflection arriving at conceptions in terms of conceivable confirmatory and disconfirmatory circumstances -- a method hospitable to the generation of explanatory hypotheses, and conducive to the employment and improvement of verification to test the truth of putative knowledge. Given abduction's dependence on mental processes not necessarily conscious and deliberate but, in any case, attuned to nature, and given abduction's being driven by the need to economize the inquiry process, its explanatory hypotheses should be optimally simple in the sense of "natural" (for which Peirce cites Galileo and which Peirce distinguishes from "logically simple"). Given abduction's insecurity, it should have consequences with conceivable practical bearing leading at least to mental tests, and, in science, lending themselves to scientific testing.

2. Deduction. Analysis of hypothesis and deduction of its consequences in order to test the hypothesis. Two stages:
i. Explication. Logical analysis of the hypothesis in order to render it as distinct as possible.
ii. Demonstration (or deductive argumentation). Deduction of hypothesis's consequence. Corollarial or, if needed, Theorematic.


3. Induction. The long-run validity of the rule of induction is deducible from the principle (presuppositional to reasoning in general) that the real is only the object of the final opinion to which adequate investigation would lead In other words, if there were something to which an inductive process involving ongoing tests or observations would never lead, then that thing would not be real. Three stages:
i. Classification. Classing objects of experience under general ideas.
ii. Probation (or direct Inductive Argumentation): Crude (the enumeration of instances) or Gradual (new estimate of proportion of truth in the hypothesis after each test). Gradual Induction is Qualitative or Quantitative; if Quantitative, then dependent on measurements, or on statistics, or on countings.
iii. Sentential Induction. "...which, by Inductive reasonings, appraises the different Probations singly, then their combinations, then makes self-appraisal of these very appraisals themselves, and passes final judgment on the whole result".

Computational approaches


Many subspecialties of applied logic and computer scienceComputer science

Computer science, or computing science, is the study of the theoretical foundations of information and computation and...
, to name a few, artificial intelligenceArtificial intelligence

Artificial intelligence is a branch of computer science that deals with intelligent behavior, learning, and adaptation in m...
, machine learningMachine learning

As a broad subfield of artificial intelligence, Machine learning is concerned with the development of algorithms and techniq...
, computational learning theoryComputational learning theory

In theoretical computer science, computational learning theory is a mathematical field related to the analysis of machine le...
, inferential statisticsInferential statistics

Inferential statistics or statistical induction comprises the use of statistics to make inferences concerning some unk...
, and knowledge representationKnowledge representation

Knowledge is different from data and information....
, are concerned with setting out computational, logical, and statistical frameworks for the various types of inference involved in scientific inquiry, in particular, hypothesis formationAbductive reasoning

Abduction, or abductive reasoning, is the process of reasoning to the best explanations....
, logical deductionDeductive reasoning

In traditional Aristotelian logic, Deductive reasoning is reasoning in which the conclusion is necessitated by, or reach...
, and empirical testingInductive reasoning

Induction or inductive reasoning, sometimes called inductive logic, is the process of reasoning in which the pre...
. Some of these applications draw on measuresMeasure (mathematics)

In mathematics, a measure is a function that assigns a number, e.g., a "size", "volume", or "probability", to subsets of a g...
 of complexityComplexity

Complexity is the opposite of simplicity....
 from algorithmic information theoryAlgorithmic information theory

Algorithmic information theory is a subfield of information theory and computer science that concerns itself with the relati...
 to guide the making of predictions from prior distributionsProbability distribution

In mathematics and statistics, a probability distribution, more properly called a probability distribution function, a...
 of experience, for example, see the complexity measure called the speed priorSpeed prior

Jrgen Schmidhuber's Speed Prior is a complexity measure similar to Kolmogorov complexity, except that it is based on computa...
from which a computable strategy for optimal inductive reasoning can be derived.

Philosophy and sociology of science


Philosophy of science looks at the underpinning logic of the scientific method, at what separates science from non-scienceDemarcation problem

The demarcation problem in the philosophy of science is about how and where to draw the lines around science....
, and the ethicResearch ethics

Research ethics involves the application of fundamental ethical principles to a variety of topics involving scientific resea...
 that is implicit in science.

We find ourselves in a world that is not directly understandable. We find that we sometimes disagree with others as to the factFact Summary

The word fact in English corresponds with a number of different meanings, some of them highly specific, depending on their c...
s of the things we see in the world around us, and we find that there are things in the world that are at odds with our present understanding. The scientific method attempts to provide a way in which we can reach agreement and understanding. A "perfect" scientific method might work in such a way that rationalRationality

In philosophy rationality and reason are the key methods used to treat the data gathered through empiricism, which stands for the ...
 application of the method would always result in agreement and understanding; a perfect method would arguably be algorithmAlgorithm

In mathematics and computing, an algorithm is a procedure for accomplishing some task which, given an initial state, will t...
ic, and so not leave any room for rational agents to disagree. As with all philosophicalPhilosophy

Philosophy is a field of study that includes diverse subfields such as aesthetics, epistemology, ethics, logic, and metaphys...
 topics, the search has been neither straightforward nor simple. Logical PositivistLogical positivism

Logical positivism is a school of philosophy that combines positivism—which states that the only authentic knowledge ...
, empiricistEmpiricism

In philosophy generally, empiricism is a theory of knowledge emphasizing the role of experience....
, falsificationistFalsifiability

In science and the philosophy of science, falsifiability, contingency, and defeasibility are roughly...
, and other theories have claimed to give a definitive account of the logic of science, but each has in turn been criticized.

Thomas Samuel KuhnThomas Samuel Kuhn

Thomas Samuel Kuhn was an American intellectual who wrote extensively on the history of science and developed several impor...
 examined the history of science in his The Structure of Scientific RevolutionsThe Structure of Scientific Revolutions

The Structure of Scientific Revolutions is an analysis of the history of science....
, and found that the actual method used by scientists differed dramatically from the then-espoused method.

Imre LakatosImre Lakatos

Imre Lakatos was a philosopher of mathematics and of science. ...
 and Thomas Kuhn have done extensive work on the "theory laden" character of observation. Kuhn (1961) said the scientist generally has a theory in mind before designing and undertaking experiments so as to make empirical observations, and that the "route from theory to measurement can almost never be traveled backward". This implies that the way in which theory is tested is dictated by the nature of the theory itself, which led Kuhn (1961, p. 166) to argue that "once it has been adopted by a profession ... no theory is recognized to be testable by any quantitative tests that it has not already passed".

Paul FeyerabendPaul Feyerabend

Paul Karl Feyerabend was an Austrian-born philosopher of science who lived in England, the United States, New Zealand, Ital...
 similarly examined the history of science, and was led to deny that science is genuinely a methodological process. In his book Against Method he argues that scientific progress is not the result of applying any particular method. In essence, he says that "anything goes", by which he meant that for any specific methodology or norm of science, successful science has been done in violation of it.
Criticisms such as his led to the strong programmeStrong programme

The strong programme is a variety of the sociology of scientific knowledge particularly associated with David Bloor, Barry B...
, a radical approach to the sociology of scienceSociology of science

Sociology of science is the subfield of sociology that deals with the practice of science....
.

In his 1958 book, Personal Knowledge, chemist and philosopher Michael PolanyiMichael Polanyi Overview

Michael Polanyi was a HungarianBritish polymath whose thought and work extended across physical chemistry, economics, and ...
 (1891-1976) criticized the common view that the scientific method is purely objective and generates objective knowledge. Polanyi cast this view as a misunderstanding of the scientific method and of the nature of scientific inquiry, generally. He argued that scientists do and must follow personal passions in appraising facts and in determining which scientific questions to investigate. He concluded that a structure of liberty is essential for the advancement of science - that the freedom to pursue science for its own sake is a prerequisite for the production of knowledge through peer review and the scientific method.

The postmodernistPostmodernism Overview

Postmodernism is an idea that has been extremely controversial and difficult to define among scholars, intellectuals, and hi...
 critiques of science have themselves been the subject of intense controversy and heated dialogue. This ongoing debate, known as the science warsScience wars

The Science wars were a series of intellectual battles in the 1990s between "postmodernists" and "realists" about the nature...
, is the result of the conflicting values and assumptions held by the postmodernistPostmodernism

Postmodernism is an idea that has been extremely controversial and difficult to define among scholars, intellectuals, and hi...
 and realistScientific realism

Scientific realism is a view in the philosophy of science about the nature of scientific success, an answer to the question ...
 camps. Whereas postmodernistsPostmodernism

Postmodernism is an idea that has been extremely controversial and difficult to define among scholars, intellectuals, and hi...
 assert that scientific knowledge is simply another discourse and not representative of any form of fundamental truth,