Lynda Stone. Encyclopedia of Qualitative Research Methods. Editor: Lisa M Given. Sage Publications, 2008.

Epistemology, according to the Oxford English Dictionary, is the theory or science of the method and ground of knowledge. It is a core area of philosophical study that includes the sources and limits, rationality and justification of knowledge. Its etymological roots are Greek from episteme (knowledge) and logos (explanation). Although it is an ancient concept, the term epistemology first appeared in English use during the mid-19th century; this gives it modern meaning. The following three questions are basic to epistemology. What is knowing? What is the known? What is knowledge? These questions have wide interest Topical Interest Group: http://www.stanford.edu/~davidf/empowermentevaluation.html for fields of inquiry but are central to the sciences broadly defined, including qualitative research. Because of its disciplinary base, this discussion deals only with matters that have concerned philosophers. Because of its modern importance, it deals primarily with relatively recent philosophy and concentrates on the 20th century and today. Following overview discussions, a central section on exemplary epistemologies suggests the underlying position of this entry—that the meaning and application of “knowledge,” as a history of philosophy suggests, has always been (and still is) dynamic, diverse, and “at bottom” diffuse. Another purpose of the entry is to introduce readers to the language of philosophy.


A history of Western epistemology reveals that the principal philosophical occupation has been what American philosopher John Dewey called “the quest for certainty.” A first aspect of this quest, or the search for foundation, has been to align philosophy with other organized bodies of inquiry that were thought to be “certain.” Across millennia, these have included religion, mathematics, logic, and science. During the 20th century, the foundations of knowledge were sought in mathematics, in the natural sciences (especially mathematical physics), and in the structures and uses of language.

A second dimension of the search for foundation has been in posing philosophical systems. Historically, many philosophical systems were posited—with each apparently thought to be the answer to the quest. The idea of a system is that a set of “founding premises” serves as a basis for asking subsequent epistemological questions. Modern but traditional examples include rationalism and empiricism, idealism and realism. Not discussed elsewhere in this encyclopedia, the rationalism of René Descartes serves as an illustration. For him, philosophy is a process in which the mind turns inward seeking foundation through reason. Employing a method of doubting all that he knew, Descartes came to a clear and distinct idea—a truth. Two were revealed: the cogito or consciousness and God. Descartes’s framework is the dualistic separate relationship of self and object. With the writings principally of Descartes, David Hume, John Locke, and Immanuel Kant, epistemology rather than metaphysics became central to modern philosophy. In general, questions arising across foundational systems focus on the relationship of person to world and to other persons, of inner immaterial mind or minds and outer material world. Additional questions include source, authority and form of knowledge, process of making a claim, and domain of application.

Perhaps the important philosophical contribution of the past century was to “give up” the quest; that is, to generally acknowledge that there is no one and only one system that founds knowledge. “-Isms” or traditions within philosophy are still posited but with a nonfoundational status. This shift basically occurred through discussions of the related roles of language and truth. A contemporary position known as “foundationalism” still holds that there are basic propositions from which nonbasic propositions can be inferred. Its contrasting position is “coherentism,” the denial of any such base.

A final point about epistemological foundations is that across Western thought and culture there have always been “other,” nonfoundational formulations. Consideration of them begins with a note about history and its contingency. It is often said that the development of philosophy, and within it epistemology, began with and has since been a footnote to Plato. It is well recognized that Plato’s views were a response to his own historical situation—to one of societal and personal political crisis. Plato’s system, thus, was an exclusionary system in which domains and processes of knowing and knowledge were theoretically possible above a “dividing line” and were not possible below the dividing line. Philosophy and absolutism were “in,” and rhetoric and sophism were “out.” And arts and poetics were “way out.” The division has continued to this day. Interestingly, there have been times when Plato’s hierarchy was reversed, or at least when the line was blurred, as in the Renaissance and the era of the Romantics and as the focus of C. P. Snow’s debate between the “two cultures” indicates.

Units, Kinds, and Processes

From Plato’s time onward, philosophers have described knowing and knowledge through a series of synonyms; that is, of what constitutes knowledge. Today, in common sense, knowledge is facts and information; today, in philosophy, knowledge is the purview of propositions or discourse. Historically, many other “inputs” and “outputs” have comprised knowledge. Philosophical questions concerned input source and output manifestation and much later concerned integrative processes of consciousness. Recognizing both external sensations and internal initiations, knowledge was perfection with units prior to modernity that included ideal forms and God’s words. These were available to “man” as imperfect appearances or ideas. Input units across time have included external perceptions and “sensa” as in Locke’s view during the 18th century. Reason has always been central to knowing and became an end in itself, for instance, in Georg Wilhelm Friedrich Hegel’s view during the 19th century. In more recent times, process units of experience and belief have resulted in product units of being, meaning, judgment, and even inference and interpretation. In contemporary traditions, belief and experience remain mediated or accessible through language. Today, language units comprise discourses that themselves are defined as knowledge; still other units related to language are game and practice.

Distinctions among kinds of knowledge have also interested philosophers. An early distinction was that between perfection and imperfection. Others include distinctions between explicit and tacit, direct and indirect, and private and public formulations. The first two pairs concern justification of knowledge, especially in the presence or absence of self-consciousness. The last pair is significant in that early modern philosophers such as Thomas Hobbes posited that external inputs placed ideas in a mind but then did not account for how private ideas became public. The key insight of Ludwig Wittgenstein during the 20th century was to deny the existence of private knowledge. A second distinction, between a priori and a posteriori knowledge, was proposed by Kant as an attempt to resolve debates between rationalism and empiricism. Related to this is that different combinations of the operation of mental faculties result in truth, goodness, and beauty. In these formulations, the latter two are derivative of the first one—intellectual formulation. Today, a priori knowledge is still defined as independent of sensory experience that defines a posteriori. Related is another distinction arising once knowledge is conceived as propositional; this is of analytic and synthetic propositions. The former are true by meaning as opposed to true based on fact. Much debate has ensued over relationships of these two paired forms of knowledge. Emerging as “setting the standard” is knowledge as propositional and tested by experience. A final example of distinctive kinds of knowledge is between “knowing that” and “knowing how.” Credited to Gilbert Ryle and for him related to consciousness, the first describes states of affairs and the second describes procedures. A recent formulation subsumes many different statements of knowledge under “knowing that.” These include facts and persons as well as states such as which, whether, and when. Qualifications also name “acquaintance knowledge,” that which is indirect by inference, and knowing how as “ability knowledge.”

Continuing from knowledge kinds, modern philosophers have attended to two basic processes of knowing. One involves the exercise of “mind” alone, and the other involves the mind’s operation on perceptual stimuli. Evolving from rationalism and empiricism, various idealisms and realisms are much stronger than Kant’s knowledge kinds because each was determined to be the source for all knowing, both of internal consciousness and of external materiality. During the past century, various philosophers also have attended to mental processes that today are thought of as intuition and cognition. Of note, except for a contemporary critical realism in social science, within philosophy these systemic processes have been supplanted by influence of the linguistic turn (discussed in the next section).

Contemporary Traditions

Twentieth-century philosophy saw a blurring, somewhat and for some theorists, of Western traditions, often named as Anglo-American and continental. It is arguably more instructive to identify two approaches to knowledge. First, the analytic approach has focused on, and continues to focus on, the rationality of knowledge; philosophers of this approach have largely explored logical and linguistic conditions of knowledge claims. Second, those from the “social” approach instead have focused on conditions of the societal function of knowledge. In common, both approaches acknowledge and work variously from what has been called the linguistic turn. Historically, two phases can be identified. A first phase sought foundation in language function and use. Developing out of a modern realism, Bertrand Russell’s analytic foundational move from mathematics to language structures is illustrative, and Ferdinand de Saussure’s continental structuralist theory of the basic linguistic sign is another example. Related to various “postmodernisms,” a second phase turned to the openness of language. Two contributors are the neopragmatist Richard Rorty, for whom knowledge and philosophy itself are conversation, and the poststructuralist Jacques Derrida, for whom a deconstruction of language, knowledge, and philosophy always operates. Across traditions today, knowledge is envisioned to a lesser or greater degree as language and as ambiguous, tentative, and fallible.

The first approach is analytic philosophy, initially identified with Russell, G. E. Moore, and Wittgenstein. It has been the dominant philosophical tradition in Anglo-American thought since the mid-20th century. Analytic philosophers posit the “standard view” of epistemology and define knowledge as justified true belief. Once the debate about truth was generally informed by Alfred Traski’s semantic theory, philosophical considerations within this approach have concentrated largely on issues of justification. The second approach, the social approach, understands knowledge as historically and discursively contextualized and, thus, as influencing its use. Here “-isms” continue to be identified, but this practice is largely inaccurate because individual philosophers are so different from each other. One sub-tradition is the classical pragmatism of C. S. Peirce, William James, and Dewey related today to a strong neopragmatism. For Dewey, pragmatist knowledge is “warranted” through persons’ enactments in environments where both are changed as a result. A second sub-tradition receiving much intellectual attention today is that of French poststructuralism. Like pragmatism, it is composed of philosophers sharing “family resemblances.” Key figures include Jean-François Lyotard, Michel Foucault, and Derrida. Too simply put and with a nod to Foucault, for them knowledge is a societal construction that often is imbricated with inequitable illusive manifestations of power.

A long-standing “nonepistemological tradition” also deserves mention. Descended from Plato’s adversaries, this is rhetoric. Historically, it is the art of fine speaking, of persuasion, grounded not in abstract truth or goodness but rather in its own form. Rhetoric also is fundamentally social. Enjoying a renewal of interest today, knowledge can be described via rhetoric—perspectival, partial, incomplete, infected by partisan desires, interests, and projects, and in recent times relative to discourses. Those for whom a rhetorical tradition has relevance believe that, indeed, all knowledge is “uncertain” in just these ways.


Working from the two broad approaches to epistemology presented in the previous section, a principal purpose of this entry—to indicate both variety and evolution—is served through illustration. Out of the analytic approach, four examples are from Russell, Wittgenstein, Willard Quine, and Edmund Gettier. During the past decades, other important writings on epistemology include those by Karl Popper, Donald Davidson, and Alvin Goldman.

British logician Bertrand Russell (1872-1920) was generally named a realist for whom all knowledge is based in experience. He posited two processes: knowledge by acquaintance (in which there is direct inference of sense data) and knowledge by description (in which there is indirect inference of sense data). Positing logical atomism, he searched for an ideal isomorphic language with which to map the world but came to see his own search as unsuccessful. His foundational analyses of mathematics and language structure initiated the modern analytic tradition.

Countering Russell in his work, Viennese-born Ludwig Wittgenstein (1889-1951) was the founder of the movement in ordinary language philosophy within the analytic tradition. Two ideas are especially important from him. One is that a word may well refer to multiple entities, and the other is that words relate to each other in family resemblances. Wittgenstein’s idiom of “language game,” that language use occurs in particular social and linguistic contexts, has had a huge influence across Anglo-American and continental philosophical traditions.

Central to analytic philosophy, Willard Van Orman Quine (1908-2000) was influenced by Wittgenstein and contributed these two ideas: a denial of the analytic-synthetic distinction in propositional content and an underdetermination and holistic interconnection of theories. Quine’s perspective came to be known as “naturalistic epistemology,” in which he argued that the empirical science of psychology ought to replace philosophy as the basis for knowledge. His view that all that can be known is the sensory cause of belief has been discredited, but a contemporary modification of his naturalism remains well respected.

Also influenced by the later Wittgenstein, the last contributor is little known outside of analytic philosophy. Edmund Gettier’s (1927-) name is attached to the “Gettier problem” from a brief article published in 1963. Its impact was to call into question knowledge as justified true belief. In a series of examples, he argued that beliefs can be both true and justified yet still not be knowledge. Much work, as indicated earlier on the issue of justification, has been written since Gettier’s argument was published.

Out of the social approach, four examples are from Dewey, Martin Heidegger, Hans-Georg Gadamer, and Foucault. During recent decades, other important contributors include U.S. philosophers Donald Davidson, Rorty, and Hilary Putnam; French philosophers Lyotard and Derrida; and the important German critical theorist Jürgen Habermas. In what follows, Dewey is a classical pragmatist, Heidegger’s philosophy is best named a phenomenology, and Gadamer offers a present-day hermeneutics. Foucault then stands in for the diverse tradition called poststructuralism.

With influences from British empiricism and idealism, American John Dewey’s (1859-1952) epistemology cannot be divorced from his political philosophy. Knowledge, or “warranted assertability,” is a process of continual inquiry in which utility is posed and justified in consequences, in action. His “reconstruction” process has traces of a Hegelian dialectic in which a particular problem, temporary solution, and new problem form the epistemological situation. Ideally, inquiry takes place within a democratic society, one that Dewey posited as the interconnecting advances of science and society.

German Martin Heidegger’s (1889-1976) philosophy of hermeneutic phenomenology has had a significant impact on much of continental social theory. Influenced greatly by Edmund Husserl, his major contribution concerns the meaning of “being” as “in itself” misunderstood across the history of Western thought. Being, always already temporally situated, points to the prefigured existence of all knowledge. His writings also attend to “technology,” a basic but potentially dangerous mode of human existence. Heidegger’s reattention to classical thought also is a model for subsequent philosophers.

German Hans-Georg Gadamer (1900-2002), a student of Heidegger’s, offers a significant project via the linguistic turn in updating classical hermeneutics, biblical/textual interpretation that sought true meaning. He posits that history, culture, and tradition fuse as “horizons” to bound any interpretation. With a method that is discursive, dialogic, and conversational, Gadamer has written across many topics for which knowledge matters; these include poetry, literature, art, politics, and ethics.

French philosopher-historian Michel Foucault (1926-1984) is identified by an English-speaking audience, arguably inappropriately, as a poststructuralist. Like all European theorists, his writings relate in some ways to humanist, phenomenological, and critical traditions—but his are a unique alternative. Foucault’s studies of social institutions reveal epistemological interconnections of discursive and nondiscursive formations in his idiom of “power knowledge.” In effect, “regimes of truth” come to be constituted and stabilized; of them, different historic eras produce different underlying rationalities. It is these that matter as knowledge use.


In this encyclopedia, entries related to the results of research are primary for qualitative researchers; knowledge and what philosophers have had to say about it are indeed central. This entry has introduced a complex topic of which other aspects are similarly interesting and important. Extensions include a study of the meaning of truth and recent movements in “alternative epistemologies.” Among these are contributions from feminist and minority scholars. Readers and researchers are encouraged to read further as they consider epistemological implications for and from their own work.