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For the hypotheses of a theorem, see Theorem. For other uses, see Hypothesis (disambiguation).
"Hypothetical" redirects here. For the 2001 progressive metal album, see Hypothetical (album).
The hypothesis of Andreas Cellarius, showing the planetary motions in eccentric and epicyclical orbits.





Remember, the way that you prove an implication is by assuming the hypothesis. --Philip Wadler[2]

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 ὑπόθεσις word hupothesis, meaning "to put under" or "to suppose".[1]

In Plato's Meno (86e–87b), Socrates dissects virtue with a method used by mathematicians,[3] that of "investigating from a hypothesis."[4] In this sense, 'hypothesis' refers to a clever idea or to a convenient mathematical approach that simplifies cumbersome calculations.[5] 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.[6]


In Entrepreneurial science, a hypothesis is used to formulate provisional ideas within a business setting. The formulated hypothesis is then evaluated where either the hypothesis is proven to be "true" or "false" through a verifiability- or falsifiability-oriented Experiment.[8][9][10]

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 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 as well.

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.[11]: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[edit]

People refer to a trial solution to a problem as a hypothesis, often called an "educated guess"[12][13] because it provides a suggested solution based on the evidence. However, some scientists reject the term "educated guess" as incorrect.[14] 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:

  • Testability (compare falsifiability as discussed above)

Working hypothesis[edit]

Main article: 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 and are often used as a conceptual framework in qualitative research.[18][19]

The provisional nature of working hypotheses make 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]


Hypotheses, concepts and measurement[edit]

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]


Statistical hypothesis testing[edit]

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.


Conventional significance levels for testing hypotheses (acceptable probabilities of wrongly rejecting a true null hypothesis) are .10, .05, and .01. 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.[25]

The above procedure is actually dependent on the number of the participants (units or sample size) that is included in the study. For instance, the sample size may be too small to reject a null hypothesis and, therefore, it is recommended to specify the 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.[26]

See also[edit]


  1. ^ a b 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. ^ Philip Wadler, 2 November 2015 Keynote: Propositions as Types. Minute 14:36 /55:28 of Code Mesh video clip
  3. ^ 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.
  4. ^ Gregory Vlastos, Myles Burnyeat (1994) Socratic studies, Cambridge ISBN 0-521-44735-6, p. 1
  5. ^ "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.
  6. ^ "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.' Public Domain This article incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "article name needed". Encyclopædia Britannica (11th ed.). Cambridge University Press. 
  8. ^ Harvard Business Review (2013) "Why Lean Startup Changes Everything"
  9. ^ Tristan Kromer 2014 "Success Metric vs. Fail Condition"
  10. ^ Lean Startup Circle "What is Lean Startup?"
  11. ^ Popper 1959
  14. ^ "Just a Theory": 7 Misused Science Words
  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 via Answers.com.


  20. ^ Patricia M. Shields and Nandhini Rangarajan. 2013. A Playbook for Research Methods: Integrating Conceptual Frameworks and Project Management]. Stillwater, OK: New Forums Press. pp. 109-157
  23. ^ a b Hempel, C. G. (1952). Fundamentals of concept formation in empirical science. Chicago, Illinois: The University of Chicago Press, p. 33.
  24. ^ Altman. DG., Practical Statistics for Medical Research, CRC Press, 1990, Section 8.5,
  26. ^ Altman. DG., Practical Statistics for Medical Research, CRC Press, 1990, Section 15.3,


External links[edit]

  • "How science works", Understanding Science by the University of California Museum of Paleontology.