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A hypothesis (foundation from ancient Greek hupothesis where hupo = under and thesis = ) is a proposed explanation for a phenomenon. A scientific hypothesis must be testable and based on previous observations or extensions of scientific theories.

Contents 1 Usage 2 Types of hypotheses 3 Experimental Hypothesis 3.1 Propositions 3.2 Empirical generalizations 4 Quotes 5 See also 6 Notes 7 External links

[edit] Usage

In early usage, a hypothesis was usually a clever idea or convenient mathematical approach that simplified cumbersome calculations; it did not necessarily have any real meaning. A famous example of the older sense is the warning which Cardinal Bellarmine issued to Galileo, that he must not treat the motion of the Earth as a reality, but merely as a hypothesis.

In common usage at present, a hypothesis is a provisional idea whose merit is to be evaluated. A hypothesis requires more work by the researcher in order to either confirm or disprove it. In the hypothetico-deductive method, a hypothesis should be falsifiable, meaning that it is possible that it be shown false, usually by observation. Note that, if confirmed, the hypothesis is not necessarily proven, but remains provisional.

The term hypothesis was misused in the Riemann hypothesis, which should be properly called a conjecture. As an example, someone who enters a new country and observes only white sheep, might form the hypothesis that all sheep in that country are white. It can be considered a hypothesis, as it is falsifiable. It can be falsified by observing a single black sheep. Provided that the experimental uncertainties are small (for example that it is a sheep, instead of a goat) and that the experimenter has correctly interpreted the statement of the hypothesis (for example, does the meaning of "sheep" include rams?), the hypothesis is falsified. IT is an If/then statement

[edit] Types of hypotheses

[edit] Experimental Hypothesis

Null hypothesis

[edit] Propositions

Propositions follow a causal order ("A causes B")

[edit] Empirical generalizations

Empirical generalizations are based on observed regularities, but they don't stipulate what is the cause and effect themselves, only stating that 'A is related to B'.

[edit] Quotes

• "Hypotheses non fingo" : "I feign no hypotheses" -- Isaac Newton¹

• "... a hypothesis is a statement whose truth is temporarily assumed, whose meaning is beyond all doubt. ..." -- Albert Einstein²

[edit] See also

• Causality
• Ecological fallacy
• Learning
• Logic
• Null hypothesis
• Philosophiae Naturalis Principia Mathematica for Newton's position on hypotheses
• Reductionism
• Research design
• Statistical hypothesis testing
• Theory

[edit] Notes

Note 1: Isaac Newton, Principia Mathematica. A New Translation by I. Bernard Cohen and Anne Whitman, translators. University of California Press 1999 ISBN 0-520-08817-4

Note 2: Letter to Eduard Study from Albert Einstein, September 25,1918 Collected Papers of Albert Einstein, J.J. Stachel and Robert Schulmann, eds. Princeton University Press 1987

[edit] External links

• Research and Evaluation Glossary

This page uses content from the English-language version of Wikipedia. The original article was at Hypothesis. The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.