Empiricism << ehm PIHR uh sihz uhm >> is a philosophical approach that views experience as the most important source of knowledge. It is the philosophical outlook of most scientists. Empiricists try to answer as many questions as possible by using information gathered by the senses. They reject attempts to decide issues on the basis of pure reason or religious or political authority.
Empiricists disagree sharply about how experience is employed in the growth of knowledge. One group of Empiricists believes that experience gained through the senses is the source of all knowledge and that all legitimate knowledge must be verifiable by sense experience. This view developed from the philosophies of George Berkeley, David Hume, John Locke, and Bertrand Russell of the United Kingdom; and Ernst Mach and philosophers called Logical Positivists in Austria. Such Empiricists rely on several presuppositions (assumptions) that have been challenged by critics.
One presupposition is that all legitimate statements must be derivable from sense experience. However, critics have pointed out that science includes many laws that cannot be verified by experience alone. A second presupposition states that sense observations are conclusive and free from theory so that theories can reliably be built on them. However, critics say that all observations are influenced by scientific theory and so cannot provide a theory-free basis for knowledge. A third presupposition identifies what is real with what can be experienced through the senses. This idea has led many Empiricists to deny the existence of a world outside our perceptions. Many scientists criticize this position because they think it runs counter to the spirit of science.
Another group of Empiricists believe that the role of sense experience and experimentation is not to justify, verify, or defend knowledge. Instead, their role is to expose theories to sharp criticism. Philosophers in this group include William Whewell of the United Kingdom, Charles Sanders Peirce of the United States, and Ludwig Boltzmann and Karl Popper of Austria.
Empiricists in this group concentrate on proving theories false, rather than true. Their approach enables them to distinguish between what is real and what can be experienced. As a result, scientific discussion is not limited to what can be observed. These Empiricists say that many important theories in the history of science have been based on factors that, at least at first, could not be perceived. The theory of the atom is one example.
