Scientific method

of *The Horse in Motion,* 1878, were used to answer the question whether all four feet of a galloping horse are ever off the ground at the same time. This demonstrates a use of photography as an experimental tool in science.
A more important use of photography in science was by Charles Darwin in his The Descent of Man, 1871.]]

The **scientific method** refers to ways to get facts, correct errors and mistakes, and test theories.

The Oxford English Dictionary says that scientific method is: "a method or procedure that has characterized natural science since the 17th century". It is observation, measurement, and experiment, plus the formulation, testing, and modification of hypotheses.

A scientist gathers empirical and measurable evidence, and uses sound reasoning. 

New knowledge often needs adjusting, or fitting into, previous knowledge.

## Criterion 
What distinguishes a scientific method of inquiry is a question known as **the criterion**'. It is an answer to the question: is there a way to tell whether a concept or theory is science, as opposed to some other kind of knowledge or belief? 

There have been many ideas as to how it should be expressed. Logical positivists thought a theory was scientific if it could be verified (proved true). 

Karl Popper thought this was a mistake. He thought a theory was not scientific unless there was some way it might be refuted (shown to be wrong). 

On the other hand, Paul Feyerabend thought there was no criterion. For him, "anything goes", or whatever works, works.

Scientists try to let reality speak for itself. They support a theory when its predictions are confirmed, and challenge it when its predictions prove false. Scientific researchers offer hypotheses as explanations of phenomena, and design experiments to test these hypotheses. Since big theories cannot be tested directly, it is done by testing predictions derived from the theory. These steps must be repeatable, to guard against mistake or confusion by any particular experimenter.

Scientific inquiry is generally intended to be as objective as possible. To reduce bias, scientists publish their work, and so share data and methods with other scientists.

## Stages 
Science and things that are not science (such as pseudoscience) are often distinguished by whether they use the scientific method. One of the first people to create an outline of the steps in the scientific method was John Stuart Mill.

There is no one scientific method. Some fields of science are based on mathematical models, such as physics. Other fields, such as social science, have rough theories. They rely more on patterns that emerge from their data. Sometimes scientists focus on testing and confirming hypotheses, but open-ended exploration is also important. Some scientific fields use laboratory experiments. Others collect observations from real-world situations. Many areas of science are quantitative, emphasizing numerical data and mathematical analysis. But some areas, especially in social science, use qualitative methods, such as interviews or detailed observations of human or animal behavior. Focusing too much one kind of method can lead us to ignore knowledge produced by other methods.

Some textbooks focus on a single, standard "scientific method". This idea of a single scientific method is based on experimental, hypothesis-testing. It doesn't apply very well to other areas of science. It is often written as a number of steps:
# **Ask a question about the world.** All scientific work begins with having a question to ask or a problem to solve.

## History 
Elements of scientific method were worked out by some early students of nature.
* "We consider it a good principle to explain the phenomena by the simplest hypothesis possible." Ptolemy (85165&nbsp;AD). This is an early example of what we call Occam's razor.
* Ibn al-Haytham (Alhazen) (965–1039), Robert Grosseteste (1175–1253) and Roger Bacon (1214–1294), all made some progress in developing scientific method.
* Scientists in the 17th century started agreeing that the experimental method is the main way to find the truth. This was done in western Europe by men like Galileo, Kepler, Hooke, Boyle, Halley and Newton. At the same time, the microscope and the telescope were invented (in Holland), and the Royal Society was formed. Instruments, societies, and publishing all helped science greatly.

## Related pages 
* Falsifiability
* Historical method
* History of science
* Philosophy of science
* Metaphilosophy
* Methodology
* Blind experiment
* Pseudoscience
* Research
* Scientific theory

## References 
## Other websites 
* Scientific method - Citizendium
* "How Do We Know What Is True?" (animated video; 2:52)