In its broadest sense, science (from the Latin scientia, meaning "knowledge") refers to any systematic knowledge-base or prescriptive practice which is capable of resulting in a prediction or predictable type of outcome. In this sense, a science is often juxtaposed with an art, which may contain elements of practice (praxis) that, because of uncontrollability or undefinability, have not been reduced to a reproducible recipe.

In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research. This article focuses on the more restricted use of the word. Science as discussed in this article is sometimes termed experimental science to differentiate it from applied science, the application of scientific research to specific human needs — though the two are often interconnected.

Science is the effort to discover and increase human understanding of how reality works. Knowledge in science is gained through research. Using controlled methods, scientists collect observable evidence of natural phenomena, record measurable data relating to the observations, and analyze this information to construct theoretical explanations of how things work. The methods of scientific research include the generation of hypotheses about how phenomena work, and experimentation that tests these hypotheses under controlled conditions. The results of this process enable better understanding of past events, and better ability to predict future events of the same kind as those that have been tested.

Scientific fields are commonly classified along two major lines: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.

Mathematics, which is sometimes classified within a third group of science called formal science, has both similarities and differences with the natural and social sciences. It is similar to empirical sciences in that it involves an objective, careful and systematic study of an area of knowledge; it is different because of its method of verifying its knowledge, using a priori rather than empirical methods.

History

main: Scientific revolution While empirical investigations of the natural world have been described since antiquity (for example, by Aristotle, Theophrastus and Pliny the Elder), and scientific methods have been employed since the Middle Ages (for example, by Ibn al-Haytham, Abu Rayhan Biruni and Roger Bacon), the dawn of modern science is generally traced back to the early modern period, during what is known as the Scientific Revolution of the 16th and 17th centuries. It was a time roughly coinciding with the later part of the Middle Ages and through the Renaissance in which scientific ideas in physics, astronomy, and biology evolved rapidly. The Greek word for science is 'επιστήμη', deriving from the verb 'επίσταμαι', which literally means 'to know'.