Abstract
The basic realist claim is that a mind-independent reality exists. It should be common sense knowledge to accept this claim, just as any theories that try to deny it soon become inconsistent because reality strikes back. In spite of this, antirealist philosophies flourish, not only in philosophy but also in the behavioral and cognitive sciences and in information science. This is highly problematic because it removes the attention from reality to subjective phenomena with no real explanatory power. Realism should not be confused with the view that all scientific claims are true or with any other kind of naiveté concerning knowledge claims. The opposite of realism may be termed antirealism, idealism, or nominalism. Although many people confuse empiricism and positivism with realism, these traditions are by nature strongly antirealist, which is why a sharp distinction should be made between empiricism and realism. Empirical research should not be founded on assumptions about “the given” of observations, but should recognize the theory-laden nature of observations. Domain analysis represents an attempt to reintroduce a realist perspective in library and information science. A realist conception of relevance, information seeking, information retrieval, and knowledge organization is outlined. Information systems of all kinds, including research libraries and public libraries, should be informed by a realist philosophy and a realist information science.