Epistemology is the branch of philosophy that investigates what knowledge is and how people know whether they know something (BonJour, 2002). It addresses questions such as: What is knowledge? How do people know if they really have knowledge? What provides a justification for any knowledge that they have? For example, on what grounds are people justified in believing that electrons have negative charge or that an accused robber is guilty? Are people convinced by sensory evidence, by testimonial evidence, by strong intuitions, or by some other means?Epistemologists, of course, have developed many ideas about how to answer questions such as these. In recent years, psychologists have become interested in whether people other than philosophers have ideas about what knowledge is and how knowledge is justified. In other words, psychologists have wondered if people have beliefs about epistemological questions (called epistemological beliefs or personal epistemological beliefs) and whether these beliefs affect in any way their learning or reasoning.

To see why these issues are important, consider the following hypothetical students, both eighth graders learning science:

  • Emily believes that the scientific knowledge she is trying to master typically has a very complex structure with rich and numerous interconnections. Sharon, on the other hand, believes that scientific knowledge has a very simple structure, consisting of lists of unrelated facts.
  • Emily believes that people know that scientific knowledge is true on the basis of observational evidence. In contrast, Sharon believes that people know that scientific knowledge is true because the textbook and her teacher say so.
  • Emily believes that scientific theories are fallible; she knows that there are often competing theories, and it sometimes takes years to work out which theories explain the observational evidence better. Sharon, however, thinks that there is only one scientific theory on any idea, and this theory is absolutely and forever true.

In summary, Emily and Sharon differ in their beliefs about the complexity of knowledge, the source of knowledge (observation versus the authority of the teacher and text), the certainty of knowledge, and whether there can be (and are) competing theories attempting to explain the same data.

Emily's and Sharon's ideas for learning and reasoning in science have several possible implications:

  1. When studying cellular processes, Emily expects to find rich interrelations among ideas, and she tries to understand them when she finds them. Sharon, on the other hand, simply tries to memorize each concept separately, never realizing that the processes are interrelated in interesting ways. In this way, beliefs about the structure of knowledge can influence learning.
  2. When conducting an experiment on seed germination, Emily finds that the seeds sprout and grow for a while even when they are kept in the dark. She realizes that when the textbook says that “plants need sunlight to grow,” this must not apply to seeds. She decides that perhaps seeds contain their own energy for initial growth. Sharon, however, assumes that she did something wrong in her experiment, because she takes her textbook at its word, and the textbook says that plants need sunlight to grow. Thus, beliefs about the source of knowledge (observations versus textbooks) affect how students reason about new evidence.
  3. When Emily reads a magazine article about conflicting studies regarding the role of carbohydrate consumption on weight control and health, she understands that much more evidence will probably be needed before matters are more fully understood. She decides to adopt a medium-carbohydrate diet, but she is aware that later evidence may make it necessary for her to change her mind. In contrast to Emily, Sharon is sure that her current ideas about the superiority of a low-carbohydrate diet are absolutely correct, because she learned about these ideas on a website written by an important doctor. She is puzzled why a magazine article would not just state the one correct theory. On this topic, it is clear that students' ability to understand competing ideas as well as how they act in response to these ideas can be affected by beliefs about the certainty of knowledge.

These examples illustrate that epistemological beliefs may have powerful effects on learning and reasoning. A growing body of research supports that such effects do exist (Mason & Boscolo, 2004; Qian & Alvermann, 1995; Schommer, 1990; Songer & Linn, 1991).


Contemporary psychological research on learners' episte-mological conceptions has its roots in the work of William Perry (1968/1999), who investigated the development of male Harvard students' ideas about knowledge during the college years. Other researchers, including Mary Belenky, Patricia King and Karen Kitchener, Marcia Baxter Magolda, and Deanna Kuhn have also investigated changes in epistemological ideas over time. This research has generally aimed to make claims about broad, overall epistemological stances expressed by individuals. For example, in Kuhn's scheme (Kuhn & Weinstock, 2002), children move from a realist epistemology (assertions are copies of reality) to an absolutist epistemology (assertions are correct or incorrect facts), and later to a multiplist epistemology (assertions are opinions, and everyone has a right to their own opinion), and finally (in some but not all people) an evaluativist epistemology (assertions are judgments based on weighing arguments on different sides of a question).

In the late 1980s, Marlene Schommer (Schommer, 1990) and others argued for an alternative approach to conceptualizing people's epistemologies. Schommer argued that epistemologies might be separable into independent beliefs. Schommer proposed three beliefs that would be called epistemological beliefs: a belief in how complex knowledge is (ranging from complex to simple), a belief in how certain knowledge is (ranging from highly certain to highly uncertain), and a belief in the source of knowledge (e.g., knowledge coming from authority). These beliefs were independent of each other. For instance, a person could believe in complex but certain knowledge, complex but uncertain knowledge, simple and certain knowledge, or simple but uncertain knowledge.

Methodologically, Schommer advanced an influential way to measure epistemological conceptions. In contrast to developmental work, which had relied principally on interviews and, to a lesser extent, on written, open-ended questions, Schommer developed a questionnaire called the Epistemological Questionnaire. Several different items were intended to measure the same underlying dimension. For example, two of the items that were intended to measure certain knowledge were (1) “Truth is unchanging” and (2) “Nothing is certain, but death and taxes.” Respondents rated agreement to each statement on a Likert scale.

Other researchers have developed analogous scales tapping overlapping but not identical sets of epistemological beliefs. For example, Barbara Hofer (2000) developed a questionnaire with items that addressed four epistemological beliefs. The questionnaire was also designed so that the questions referred to a specific field. That is, the questions did not refer to knowledge in general but to knowledge in a specific field such as science or mathematics. The first two epistemological beliefs were about the nature of knowledge:

  • Certainty. This belief refers to the extent to which the respondent thinks that knowledge is certain versus fallible and subject to change.
  • Simplicity. This refers to the extent to which the respondent believes that knowledge is structured and organized in simple ways with a single right answer rather than in more complex ways with more than one right answer.

The third and fourth beliefs address how a person comes to “know” something.

  • Source of knowledge. This belief references where knowledge comes from—from oneself (and one's own experiences) or from others (such as the teacher, the textbook writer, or experts in a field).
  • Justification of knowledge. Closely related to the source of knowledge, this belief is about the kinds of justifications that are offered in support of knowledge. Justifications might be on the basis of personal experience or the authority of experts.


Epistemological beliefs have been measured educational psychologists in different ways and for different reasons. One variation depends on how epistemology is understood. This can range from very narrow to extremely broad theoretical concepts.

There are also many methods for measurement that are not necessarily related to one's theoretical understanding of epistemology. These methods vary according to the preference of the researcher, trends in educational research, and the compatibility of the method to the field and/or context.

Some of the qualitative methods have depended on case studies in which a general question such as: “What stands out to you about the year so far?” is posed to a sample of students. In other quantitative instances, researchers measure specific factors in surveys such as, “belief scales,” where students indicate, on a scale of one to five, how much they agree with the statement: “Hard work can increase one's ability to do math.”

The context of each study provides another degree of precision. Epistemological beliefs are researched in subject or grade specific contexts, from comparative and multi-cultural perspectives, and within discourse of race, class, and gender. This large variety of subject matter denotes the especially broad and important nature of the study of epistemological beliefs in education and beyond.

Samuel Rocha

Other researchers have used items from these scales and have developed their own items to construct new measures.

Though inspired by the philosophical literature, research by psychologists and educational psychologists on epistemological beliefs has not been tightly linked to the philosophical literature. There are relatively few citations of the epistemological literature in psychological and educational articles about epistemological beliefs. There has been somewhat more connection to the philosophical literature by researchers in the epistemological development tradition, especially in the seminal work of William Perry.

In a 2005 study Clark Chinn and Ala Samarapun-gavan (have argued that closer attention to philosophical research would suggest many other kinds of epistemolog-ical beliefs that could be explored by researchers. For example, psychologists have not explored people's beliefs about social processes of knowledge construction (e.g., are processes such as peer review or interactive argumentation conductive to arriving at true ideas?) or people's beliefs about evidence (what exactly counts as evidence? How should one respond to anomalous evidence?)


One issue that has arisen with respect to measures of epis-temological beliefs is the need to distinguish between epis-temological beliefs and beliefs about learning. Barbara Hofer and Paul Pintrich (1997) argued that researchers have sometimes confused these two related but distinct sets of beliefs. An epistemological belief is a belief about the nature of knowledge or how one comes to believe that it is knowledge. A belief about learning is a belief about how people come to understand and remember ideas—regardless of whether they believed them or not. For example, the belief that “knowledge is complex” is a belief about the nature of knowledge but says nothing about how people learn that knowledge. In contrast, the belief that one can learn ideas quickly is not a belief about what knowledge is or how one comes to know or believe it, but rather a belief about how one comes to learn the ideas. Indeed, one can learn something which is not viewed as knowledge at all (e.g., one can learn about astrology while believing ittobe bunk). One can believe that knowledge is justified on the basis of observational evidence collected by experts (an epistemological belief) yet believe that the best way to learn that knowledge is by having a teacher explain it quickly (a learning belief). Learning is about understanding and remembering. Episte-mology is about the criteria for deciding that something is true.


During the growth of research on epistemological development and epistemological beliefs by educational and developmental psychologists, a second body of research on epistemological beliefs was being conducted by science educators. Most science educators have characterized their research as investigating students' beliefs or ideas about the Nature of Science (NOS). Research on NOS has been growing rapidly since the 1970s and 1980s. Two figures important in inspiring research on NOS were Richard Duschl and Norman Lederman. Duschl made a compelling claim that work by philosophers of science was highly relevant to many aspects of science education; he argued that science educators should align their ideas about the goals and practices of science with what was being learned by philosophers and historians of science. Science educators have responded to this call by investigating the understanding of NOS by both scientists and by students. Science educators have also linked their work more explicitly than educational psychologists have to the philosophical literature, especially to the work of Thomas Kuhn (1922–1996).

Research on students' understanding of NOS has, as one would expect, focused on epistemological issues related to science. The VNOS (Views of Nature of Science Questionnaire) was developed by Lederman and has been since refined by a number of others, including Fouad abd-el-Khalick. In its most recent version, a few of the questions are:

  • What makes science different from other disciplines of inquiry (e.g., religion, philosophy)?
  • Does the development of scientific knowledge require experiments? Why or why not?
  • After scientists have developed a scientific theory (e.g., atomic theory, evolution theory), does the theory ever change? Why or why not? Give examples.
  • Is there a difference between a scientific theory and a scientific law? Give examples.
  • Science textbooks often represent the atom as a central nucleus composed of protons (positively charged particles) and neutrons (neutral particles) with electrons (negatively charged particles) orbiting the nucleus. How certain are scientists about the structure of the atom? What specific evidence do you think scientists used to determine what an atom looks like?

These questions are centered around what science is, whether scientific knowledge changes, what scientific knowledge is based on (e.g., experiments), and so on. Other questions address how social and cultural values influence science. Another frequently used interview protocol has been developed by Carol and colleagues (Smith, Maclin, Houghton, & Hennessey, 2000).

Interestingly, at about the same time that educational psychologists began to rely less on interview measures and more on written questionnaire measures of epistemological beliefs, science educators moved in the opposite direction. Whereas early investigations of students' understanding of NOS tended to use questionnaires, more recent work has favored interviews and open-ended written questions of the sort presented above.


Most researchers would probably argue that promoting more sophisticated epistemological beliefs is a worthy educational goal in its own right. This is particularly true of science educators, as national and state standards explicitly say that part of learning science is coming to understand the nature of science. Most researchers would also agree that developing more sophisticated epistemo-logical beliefs can also benefit other aspects of learning. A large research effort has been devoted to investigating correlations between epistemological beliefs and performance on learning and reasoning tasks. Although a comprehensive summary of findings is beyond the scope of this entry, here are a few typical findings: (1) Students who believe that knowledge is certain write essays that reach unqualified conclusions, even when there is evidence supporting different viewpoints, as well (Schommer, 1990). (2) Students who believe that knowledge consists of ideas that are interconnected (rather than a disconnected series of facts) are better able to understand texts that present alternative positions on controversial ideas (Kardash & Scholes, 1996). (3) Students with more sophisticated epistemological beliefs were better able to learn from an inquiry-based learning environment (Wind-schitl & Andre, 1998).

These findings should not be interpreted as showing that there are always strong relationships between measure of epistemological beliefs and measure of learning and reasoning. Some have found little relationship, for example, between reasoning and beliefs about the nature of science, and students who exhibit strong progress in reasoning better may show no gains at all in epistemo-logical beliefs (Sandoval & Morrison, 2003). In addition, correlations between epistemological beliefs and measures of learning and reasoning are often relatively low.


Many researchers investigating learners' epistemologies have proceeded on the assumption that people do in fact have at least tacit beliefs about knowledge that they can express. Other researchers have questioned this assumption. David Hammer and his colleagues (Hammer & Elby, 2002, 2003) are among those who have argued that most people (other than philosophers) probably do not think about knowledge at all. On the other hand, even if people do not have actual beliefs about knowledge, they do make decisions about what counts as knowledge and what they believe. These decisions are guided by epistemological commitments which are wholly tacit, and which cannot be readily expressed. Alternatively, one can view people as engaged in epistemic practices even if they do not have explicit epistemological beliefs. The term epistemic indicates that an activity is oriented to deciding what to believe and why to believe it. A child who decides that bugs have six legs because she has just picked up a bug and counted the legs has engaged in an epistemic activity of forming a belief that bugs have six legs on the basis of her personal observations.

People do form beliefs, and by examining the basis on which they form beliefs, researchers can identify their epistemological commitments or epistemic practices. Ala Samarapungavan (1992) conducted a study in which she assessed children's epistemological commitments by observing the theory choices they made. She gave children different theories to consider and different configurations of evidence bearing on those theories. She found that even seven year olds preferred logically consistent to logically inconsistent theories. They also preferred theories that explained more evidence (as opposed to less evidence) and theories that were not inconsistent with any evidence. Through this study, Samarapungavan was able to show that even young children share some of the epistemological commitments often attributed to scientists—a preference for simplicity, consistency with the evidence, and coverage of the broadest possible scope of evidence.


Researchers interested in personal epistemologies have investigated the extent to which epistemological beliefs and epistemic practices are domain-specific. A domain-specific belief is one that is limited to a particular domain (such as mathematics, physics, and so on). For instance, a person might believe that knowledge is certain in math but not in other disciplines. A domain-general belief is one that applies generally to all or many domains. A person who believes that all knowledge in all domains is certain has a domain-general belief.

Researchers have found evidence that epistemologi-cal beliefs are domain-specific. For example, Hofer (2000) compared undergraduates' beliefs about knowledge in science with their beliefs about knowledge in psychology. The undergraduates believed that knowledge was more certain and more attainable in science than in psychology. Knowledge in psychology was justified on more personal bases than knowledge in science, which was viewed as based more on authority.

Hammer and his colleagues (Hammer & Elby, 2002, 2003; Rosenberg, Hammer, & Phelan, 2006) have argued for a much more radically contextual view of personal epistemologies. They argue that epistemologies shift very rapidly from one context to another. For instance, students who are working in a science class may at one moment view knowledge about the rock cycle as propagated stuff (information told to them by a textbook or a teacher) consisting of meaningless, isolated facts, and one or two minutes later, the same students working on the same topic may shift dramatically to viewing the same knowledge as fabricated stuff (ideas that they are creating themselves) composed of meaningful ideas that they are trying to make sense of. Radical shifts in epistemic practices can be triggered very quickly by shifts in environmental cues. In this view, people do not have stable epistemologies at all.

Research on personal epistemologies is thriving, with alternative theories being advanced and tested and a new measurement tools being developed. The steady increase in the number of researchers investigating this topic suggests that ideas about epistemologies and epistemo-logical development will play an important role in theorizing about how people learn and reason.


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