Hypothesis

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The hypothesis of Andreas Cellarius, showing the planetary motions in eccentric and epicyclical orbits Cellarius Harmonia Macrocosmica - Hypothesis Ptolemaica.jpg
The hypothesis of Andreas Cellarius, showing the planetary motions in eccentric and epicyclical orbits

A hypothesis (pl.: hypotheses) is a proposed explanation for a phenomenon. A scientific hypothesis must be based on observations and make a testable and reproducible prediction about reality, in a process beginning with an educated guess or thought. A working hypothesis is a provisionally-accepted hypothesis used for the purpose of pursuing further progress in research.

Contents

If a hypothesis is repeatedly demonstrated by experiment to be true, it may become a scientific theory. [1] [2] In colloquial usage, the words "hypothesis" and "theory" are often used interchangeably, but this is incorrect in the context of science.

A different meaning of the term hypothesis is used in formal logic, to denote the antecedent of a proposition; thus in the proposition "If P, then Q", P denotes the hypothesis (or antecedent); Q can be called a consequent. P is the assumption in a (possibly counterfactual) What If question. The adjective hypothetical, meaning "having the nature of a hypothesis", or "being assumed to exist as an immediate consequence of a hypothesis", can refer to any of these meanings of the term "hypothesis".

Uses

In its ancient usage, hypothesis referred to a summary of the plot of a classical drama. The English word hypothesis comes from the ancient Greek word ὑπόθεσις hypothesis whose literal or etymological sense is "putting or placing under" and hence in extended use has many other meanings including "supposition". [1] [3] [4] [5]

In Plato's Meno (86e–87b), Socrates dissects virtue with a method used by mathematicians, [6] that of "investigating from a hypothesis". [7] In this sense, 'hypothesis' refers to a clever idea or to a convenient mathematical approach that simplifies cumbersome calculations. [8] Cardinal Bellarmine gave a famous example of this usage in the warning issued to Galileo in the early 17th century: that he must not treat the motion of the Earth as a reality, but merely as a hypothesis. [9]

In common usage in the 21st century, a hypothesis refers to a provisional idea whose merit requires evaluation. For proper evaluation, the framer of a hypothesis needs to define specifics in operational terms. A hypothesis requires more work by the researcher in order to either confirm or disprove it. In due course, a confirmed hypothesis may become part of a theory or occasionally may grow to become a theory itself. Normally, scientific hypotheses have the form of a mathematical model. [10] Sometimes, but not always, one can also formulate them as existential statements, stating that some particular instance of the phenomenon under examination has some characteristic and causal explanations, which have the general form of universal statements, stating that every instance of the phenomenon has a particular characteristic.[ clarification needed ]

In entrepreneurial setting, a hypothesis is used to formulate provisional ideas about the attributes of products or business models. The formulated hypothesis is then evaluated, where the hypothesis is proven to be either "true" or "false" through a verifiability- or falsifiability-oriented experiment. [11] [12]

Any useful hypothesis will enable predictions by reasoning (including deductive reasoning). It might predict the outcome of an experiment in a laboratory setting or the observation of a phenomenon in nature. The prediction may also invoke statistics and only talk about probabilities. Karl Popper, following others, has argued that a hypothesis must be falsifiable, and that one cannot regard a proposition or theory as scientific if it does not admit the possibility of being shown to be false. Other philosophers of science have rejected the criterion of falsifiability or supplemented it with other criteria, such as verifiability (e.g., verificationism) or coherence (e.g., confirmation holism). The scientific method involves experimentation to test the ability of some hypothesis to adequately answer the question under investigation. In contrast, unfettered observation is not as likely to raise unexplained issues or open questions in science, as would the formulation of a crucial experiment to test the hypothesis. A thought experiment might also be used to test the hypothesis.

In framing a hypothesis, the investigator must not currently know the outcome of a test or that it remains reasonably under continuing investigation. Only in such cases does the experiment, test or study potentially increase the probability of showing the truth of a hypothesis. [13] : pp17, 49–50  If the researcher already knows the outcome, it counts as a "consequence" — and the researcher should have already considered this while formulating the hypothesis. If one cannot assess the predictions by observation or by experience, the hypothesis needs to be tested by others providing observations. For example, a new technology or theory might make the necessary experiments feasible.

Scientific hypothesis

A trial solution to a problem is commonly referred to as a hypothesis—or, often, as an "educated guess" [14] [2] —because it provides a suggested outcome based on the evidence. However, some scientists reject the term "educated guess" as incorrect. Experimenters may test and reject several hypotheses before solving the problem.

According to Schick and Vaughn, [15] researchers weighing up alternative hypotheses may take into consideration:

Working hypothesis

A working hypothesis is a hypothesis that is provisionally accepted as a basis for further research [16] in the hope that a tenable theory will be produced, even if the hypothesis ultimately fails. [17] Like all hypotheses, a working hypothesis is constructed as a statement of expectations, which can be linked to the exploratory research purpose in empirical investigation. Working hypotheses are often used as a conceptual framework in qualitative research. [18] [19]

The provisional nature of working hypotheses makes them useful as an organizing device in applied research. Here they act like a useful guide to address problems that are still in a formative phase. [20]

In recent years, philosophers of science have tried to integrate the various approaches to evaluating hypotheses, and the scientific method in general, to form a more complete system that integrates the individual concerns of each approach. Notably, Imre Lakatos and Paul Feyerabend, Karl Popper's colleague and student, respectively, have produced novel attempts at such a synthesis.

Hypotheses, concepts and measurement

Concepts in Hempel's deductive-nomological model play a key role in the development and testing of hypotheses. Most formal hypotheses connect concepts by specifying the expected relationships between propositions. When a set of hypotheses are grouped together, they become a type of conceptual framework. When a conceptual framework is complex and incorporates causality or explanation, it is generally referred to as a theory. According to noted philosopher of science Carl Gustav Hempel,

An adequate empirical interpretation turns a theoretical system into a testable theory: The hypothesis whose constituent terms have been interpreted become capable of test by reference to observable phenomena. Frequently the interpreted hypothesis will be derivative hypotheses of the theory; but their confirmation or disconfirmation by empirical data will then immediately strengthen or weaken also the primitive hypotheses from which they were derived. [21] : 36 

Hempel provides a useful metaphor that describes the relationship between a conceptual framework and the framework as it is observed and perhaps tested (interpreted framework). "The whole system floats, as it were, above the plane of observation and is anchored to it by rules of interpretation. These might be viewed as strings which are not part of the network but link certain points of the latter with specific places in the plane of observation. By virtue of those interpretative connections, the network can function as a scientific theory." [21] : 36  Hypotheses with concepts anchored in the plane of observation are ready to be tested. In "actual scientific practice the process of framing a theoretical structure and of interpreting it are not always sharply separated, since the intended interpretation usually guides the construction of the theoretician". [21] : 33  It is, however, "possible and indeed desirable, for the purposes of logical clarification, to separate the two steps conceptually". [21] : 33 

Statistical hypothesis testing

When a possible correlation or similar relation between phenomena is investigated, such as whether a proposed remedy is effective in treating a disease, the hypothesis that a relation exists cannot be examined the same way one might examine a proposed new law of nature. In such an investigation, if the tested remedy shows no effect in a few cases, these do not necessarily falsify the hypothesis. Instead, statistical tests are used to determine how likely it is that the overall effect would be observed if the hypothesized relation does not exist. If that likelihood is sufficiently small (e.g., less than 1%), the existence of a relation may be assumed. Otherwise, any observed effect may be due to pure chance.

In statistical hypothesis testing, two hypotheses are compared. These are called the null hypothesis and the alternative hypothesis. The null hypothesis is the hypothesis that states that there is no relation between the phenomena whose relation is under investigation, or at least not of the form given by the alternative hypothesis. The alternative hypothesis, as the name suggests, is the alternative to the null hypothesis: it states that there is some kind of relation. The alternative hypothesis may take several forms, depending on the nature of the hypothesized relation; in particular, it can be two-sided (for example: there is some effect, in a yet unknown direction) or one-sided (the direction of the hypothesized relation, positive or negative, is fixed in advance). [22]

Conventional significance levels for testing hypotheses (acceptable probabilities of wrongly rejecting a true null hypothesis) are .10, .05, and .01. The significance level for deciding whether the null hypothesis is rejected and the alternative hypothesis is accepted must be determined in advance, before the observations are collected or inspected. If these criteria are determined later, when the data to be tested are already known, the test is invalid. [23]

The above procedure is actually dependent on the number of the participants (units or sample size) that are included in the study. For instance, to avoid having the sample size be too small to reject a null hypothesis, it is recommended that one specify a sufficient sample size from the beginning. It is advisable to define a small, medium and large effect size for each of a number of important statistical tests which are used to test the hypotheses. [24]

Honours

Mount Hypothesis in Antarctica is named in appreciation of the role of hypothesis in scientific research.

List

Several hypotheses have been put forth, in different subject areas:

See also

Related Research Articles

<span class="mw-page-title-main">Empirical research</span> Research using empirical evidence

Empirical research is research using empirical evidence. It is also a way of gaining knowledge by means of direct and indirect observation or experience. Empiricism values some research more than other kinds. Empirical evidence can be analyzed quantitatively or qualitatively. Quantifying the evidence or making sense of it in qualitative form, a researcher can answer empirical questions, which should be clearly defined and answerable with the evidence collected. Research design varies by field and by the question being investigated. Many researchers combine qualitative and quantitative forms of analysis to better answer questions that cannot be studied in laboratory settings, particularly in the social sciences and in education.

<span class="mw-page-title-main">Falsifiability</span> Property of a statement that can be logically contradicted

Falsifiability is a deductive standard of evaluation of scientific theories and hypotheses, introduced by the philosopher of science Karl Popper in his book The Logic of Scientific Discovery (1934). A theory or hypothesis is falsifiable if it can be logically contradicted by an empirical test.

<span class="mw-page-title-main">Karl Popper</span> Austrian–British philosopher of science (1902–1994)

Sir Karl Raimund Popper was an Austrian–British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the classical inductivist views on the scientific method in favour of empirical falsification. According to Popper, a theory in the empirical sciences can never be proven, but it can be falsified, meaning that it can be scrutinised with decisive experiments. Popper was opposed to the classical justificationist account of knowledge, which he replaced with critical rationalism, namely "the first non-justificational philosophy of criticism in the history of philosophy".

<span class="mw-page-title-main">Scientific method</span> Interplay between observation, experiment, and theory in science

The scientific method is an empirical method for acquiring knowledge that has been referred to while doing science since at least the 17th century. The scientific method involves careful observation coupled with rigorous scepticism, because cognitive assumptions can distort the interpretation of the observation. Scientific inquiry includes creating a testable hypothesis through inductive reasoning, testing it through experiments and statistical analysis, and adjusting or discarding the hypothesis based on the results.

<span class="mw-page-title-main">Statistical hypothesis test</span> Method of statistical inference

A statistical hypothesis test is a method of statistical inference used to decide whether the data sufficiently supports a particular hypothesis. A statistical hypothesis test typically involves a calculation of a test statistic. Then a decision is made, either by comparing the test statistic to a critical value or equivalently by evaluating a p-value computed from the test statistic. Roughly 100 specialized statistical tests have been defined.

A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be scientific, belong to a non-scientific discipline, or no discipline at all. Depending on the context, a theory's assertions might, for example, include generalized explanations of how nature works. The word has its roots in ancient Greek, but in modern use it has taken on several related meanings.

<span class="mw-page-title-main">Philosophy of science</span>

Philosophy of science is the branch of philosophy concerned with the foundations, methods, and implications of science. Amongst its central questions are the difference between science and non-science, the reliability of scientific theories, and the ultimate purpose and meaning of science as a human endeavour. Philosophy of science focuses on metaphysical, epistemic and semantic aspects of scientific practice, and overlaps with metaphysics, ontology, logic, and epistemology, for example, when it explores the relationship between science and the concept of truth. Philosophy of science is both a theoretical and empirical discipline, relying on philosophical theorising as well as meta-studies of scientific practice. Ethical issues such as bioethics and scientific misconduct are often considered ethics or science studies rather than the philosophy of science.

<span class="mw-page-title-main">Experiment</span> Scientific procedure performed to validate a hypothesis

In common usage and science, an experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. Experiments vary greatly in goal and scale but always rely on repeatable procedure and logical analysis of the results. There also exist natural experimental studies.

<span class="mw-page-title-main">Abductive reasoning</span> Inference seeking the simplest and most likely explanation

Abductive reasoning is a form of logical inference that seeks the simplest and most likely conclusion from a set of observations. It was formulated and advanced by American philosopher and logician Charles Sanders Peirce beginning in the latter half of the 19th century.

A scientific theory is an explanation of an aspect of the natural world and universe that can be repeatedly tested and corroborated in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results. Where possible, theories are tested under controlled conditions in an experiment. In circumstances not amenable to experimental testing, theories are evaluated through principles of abductive reasoning. Established scientific theories have withstood rigorous scrutiny and embody scientific knowledge.

Scientific evidence is evidence that serves to either support or counter a scientific theory or hypothesis, although scientists also use evidence in other ways, such as when applying theories to practical problems. Such evidence is expected to be empirical evidence and interpretable in accordance with the scientific method. Standards for scientific evidence vary according to the field of inquiry, but the strength of scientific evidence is generally based on the results of statistical analysis and the strength of scientific controls.

In scientific research, the null hypothesis is the claim that the effect being studied does not exist. The null hypothesis can also be described as the hypothesis in which no relationship exists between two sets of data or variables being analyzed. If the null hypothesis is true, any experimentally observed effect is due to chance alone, hence the term "null". In contrast with the null hypothesis, an alternative hypothesis is developed, which claims that a relationship does exist between two variables.

The following outline is provided as an overview of and topical guide to the scientific method:

<span class="mw-page-title-main">Hypothetico-deductive model</span> Proposed description of the scientific 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 outcome is not yet known. A test outcome that could have and does run contrary to predictions of the hypothesis is taken as a falsification of the hypothesis. A test outcome that could have, but does not run contrary to the hypothesis corroborates the theory. It is then proposed to compare the explanatory value of competing hypotheses by testing how stringently they are corroborated by their predictions.

Testability is a primary aspect of science and the scientific method. There are two components to testability:

  1. Falsifiability or defeasibility, which means that counterexamples to the hypothesis are logically possible.
  2. The practical feasibility of observing a reproducible series of such counterexamples if they do exist.

Verificationism, also known as the verification principle or the verifiability criterion of meaning, is a doctrine in philosophy which asserts that a statement is meaningful only if it is either empirically verifiable or a tautology. Verificationism rejects statements of metaphysics, theology, ethics and aesthetics as meaningless in conveying truth value or factual content, though they may be meaningful in influencing emotions or behavior.

Inductivism is the traditional and still commonplace philosophy of scientific method to develop scientific theories. Inductivism aims to neutrally observe a domain, infer laws from examined cases—hence, inductive reasoning—and thus objectively discover the sole naturally true theory of the observed.

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.

A working hypothesis is a hypothesis that is provisionally accepted as a basis for further ongoing research in the hope that a tenable theory will be produced, even if the hypothesis ultimately fails. Like all hypotheses, a working hypothesis is constructed as a statement of expectations, which can be linked to deductive, exploratory research in empirical investigation and is often used as a conceptual framework in qualitative research. The term "working" indicates that the hypothesis is subject to change.

Bold hypothesis or bold conjecture is a concept in the philosophy of science of Karl Popper, first explained in his debut The Logic of Scientific Discovery (1935) and subsequently elaborated in writings such as Conjectures and Refutations: The Growth of Scientific Knowledge (1963). The concept is nowadays widely used in the philosophy of science and in the philosophy of knowledge. It is also used in the social and behavioural sciences.

References

  1. 1 2 Hilborn, Ray; Mangel, Marc (1997). The ecological detective: confronting models with data. Princeton University Press. p. 24. ISBN   978-0-691-03497-3 . Retrieved 22 August 2011.
  2. 1 2 "In general we look for a new law by the following process. First we guess it. ...", —Richard Feynman (1965) The Character of Physical Law p.156
  3. ↑ Supposition is itself a Latinate analogue of hypothesis as both are compound words constructed from words meaning respectively "under, below" and "place, placing, putting" in either language, Latin or Greek.
  4. ↑ Harper, Douglas. "hypothesis". Online Etymology Dictionary .
  5. ↑ ὑπόθεσις . Liddell, Henry George ; Scott, Robert ; A Greek–English Lexicon at the Perseus Project.
  6. ↑ Wilbur R. Knorr, "Construction as existence proof in ancient geometry", p. 125, as selected by Jean Christianidis (ed.), Classics in the history of Greek mathematics, Kluwer.
  7. ↑ Gregory Vlastos, Myles Burnyeat (1994) Socratic studies, Cambridge ISBN   0-521-44735-6, p. 1
  8. ↑ "Neutral hypotheses, those of which the subject matter can never be directly proved or disproved, are very numerous in all sciences." — Morris Cohen and Ernest Nagel (1934) An introduction to logic and scientific method p. 375. New York: Harcourt, Brace, and Company.
  9. ↑ "Bellarmine (Ital. Bellarmino), Roberto Francesco Romolo", Encyclopædia Britannica, Eleventh Edition.: 'Bellarmine did not proscribe the Copernican system ... all he claimed was that it should be presented as a hypothesis until it should receive scientific demonstration.' Wikisource-logo.svg This article incorporates text from a publication now in the public domain :  Chisholm, Hugh, ed. (1911). "Hypothesis". Encyclopædia Britannica . Vol. 14 (11th ed.). Cambridge University Press. p. 208.
  10. ↑ Crease, Robert P. (2008) The Great Equations ISBN   978-0-393-06204-5, p.112 lists the conservation of energy as an example of accounting a constant of motion. Hypothesized by Sadi Carnot, truth demonstrated by James Prescott Joule, proven by Emmy Noether.
  11. ↑ Blank, Steve (May 2013). "Harvard Business Review (2013) "Why Lean Startup Changes Everything"". Harvard Business Review. Archived from the original on 2021-10-28. Retrieved 2015-07-16.
  12. ↑ "Lean Startup Circle "What is Lean Startup?"". Archived from the original on 2015-07-16. Retrieved 2015-07-16.
  13. ↑ Popper 1959
  14. ↑ "When it is not clear under which law of nature an effect or class of effect belongs, we try to fill this gap by means of a guess. Such guesses have been given the name conjectures or hypotheses.", Hans Christian Ørsted(1811) "First Introduction to General Physics" ¶18. Selected Scientific Works of Hans Christian Ørsted, ISBN   0-691-04334-5 p.297
  15. ↑ Schick, Theodore; Vaughn, Lewis (2002). How to think about weird things: critical thinking for a New Age. Boston: McGraw-Hill Higher Education. ISBN   0-7674-2048-9.
  16. ↑ Oxford Dictionary of Sports Science & Medicine. Eprint Archived 2011-11-27 at the Wayback Machine via Answers.com.
  17. ↑ See in "hypothesis", Century Dictionary Supplement, v. 1, 1909, New York: The Century Company. Reprinted, v. 11, p. 616 (via Internet Archive) of the Century Dictionary and Cyclopedia, 1911.
    hypothesis [...]—Working hypothesis, a hypothesis suggested or supported in some measure by features of observed facts, from which consequences may be deduced which can be tested by experiment and special observations, and which it is proposed to subject to an extended course of such investigation, with the hope that, even should the hypothesis thus be overthrown, such research may lead to a tenable theory.
  18. ↑ Patricia M. Shields, Hassan Tajalli (2006). "Intermediate Theory: The Missing Link in Successful Student Scholarship". Journal of Public Affairs Education. 12 (3): 313–334. doi:10.1080/15236803.2006.12001438. S2CID   141201197.
  19. ↑ Patricia M. Shields (1998). "Pragmatism As a Philosophy of Science: A Tool For Public Administration". In Jay D. White (ed.). Research in Public Administration. Vol. 4. Emerald Group Publishing Limited. pp. 195–225 [211]. ISBN   1-55938-888-9. Archived from the original on 2012-03-20. Retrieved 2011-07-07.
  20. ↑ Patricia M. Shields and Nandhini Rangarajan. 2013. A Playbook for Research Methods: Integrating Conceptual Frameworks and Project Management [ permanent dead link ]. Stillwater, OK: New Forums Press. pp. 109–157
  21. 1 2 3 4 Hempel, C. G. (1952). Fundamentals of Concept Formation in Empirical Science. Chicago: University of Chicago Press.
  22. ↑ Altman. DG., Practical Statistics for Medical Research, CRC Press, 1990, Section 8.5,
  23. ↑ Mellenbergh, G.J.(2008). Chapter 8: Research designs: Testing of research hypotheses. In H.J. Adèr & G.J. Mellenbergh (eds.) (with contributions by D.J. Hand), Advising on Research Methods: A consultant's companion (pp. 183–209). Huizen, The Netherlands: Johannes van Kessel Publishing
  24. ↑ Altman. DG., Practical Statistics for Medical Research, CRC Press, 1990, Section 15.3,

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