1. an approach to epistemology holding that all knowledge of matters of fact either arises from experience or requires experience for its validation. In particular, empiricism denies the possibility of innate ideas, arguing that the mind at birth is like a blank sheet of paper (see tabula rasa). During the 17th and 18th centuries, empiricism was developed as a systematic approach to philosophy in the work of John Locke, George Berkeley, and David Hume. These thinkers also developed theories of associationism to explain how even the most complex mental concepts can be derived from simple sense experiences. Although there is a strong emphasis on empiricism in psychology, this can take different forms. Some approaches to psychology hold that sensory experience is the origin of all knowledge and thus, ultimately, of personality, character, beliefs, emotions, and behavior. Behaviorism is the purest example of empiricism in this sense. Advocates of other theoretical approaches to psychology, such as phenomenology, argue that the definition of experience as only sensory experience is too narrow; this enables them to reject the position that all knowledge arises from the senses while also claiming to adhere to a type of empiricism.

2. the view that experimentation is the most important, if not the only, foundation of scientific knowledge and the means by which individuals evaluate truth claims or the adequacy of theories and models.

3. in philosophy, the position that all linguistic expressions that are not tautologous must be empirically verifiable if they are to be deemed valid or meaningful. This principle was essential to the philosophy of logical positivism. See also positivism. —empiricist adj., n.