Glossary

Knowledge that is dependent on, or gained through, sense experience. A posteriori truths are truths known after experience.

Knowledge gained without sense experience. A priori truths are truths known prior to experience.

A type of reasoning that attempts to form the best explanation of available data.

Knowledge-how.

Knowing a person, place, or thing.

The study of ignorance, especially when ignorance is caused or influenced by groups who have an interest in that ignorance.

An argument put forward by the first-century Pyrrhonist philosopher Agrippa for global skepticism about justification (and hence knowledge). This argument begins with the observation that, for a belief B to be justified, the chain of reasons ultimately leading to B must have one of three possible structures: the chain is either (a) finite and linear, (b) circular, or (c) infinite. The next step is to argue that each possible structure is problematic, then draw the conclusion that there is no possible way for a belief to be justified.

A truth that holds in virtue of the meanings of the words in a sentence (and the sentence’s logical form). In an analytic sentence, the predicate term is contained in, or is the meaning of, the subject term. Therefore, analytic truths are true by definition.

The attachment of meaning to a perceptual input based on our past and present experiences and concepts.

The “turn,” or major shift, among many epistemologists toward an emphasis on real-world applications (e.g., in politics, education, and everyday life).

The study of value.

Ignoring a prior probability (or base rate) when determining a posterior probability.

A belief that is not formed on the basis of any other belief(s).

A formula in probability theory attributed to Reverend Thomas Bayes. The formula is used by Bayesians to describe how to update the probability of a hypothesis H given new evidence E:
P(H|E) = [{P(E|H) ∙ P(H)}/P(E)], where P(E) ≠ 0.

The study of knowledge and justified belief within a degreed framework using formal methods, especially probability theory with emphasis on Bayes’s theorem.

In the context of this book (unless otherwise specified), “belief” refers to “belief-that,” which is the acceptance of a proposition’s truth. In other contexts, “belief” can refer to “belief-in,” which need not have a proposition as its object (e.g., “I believe in you.”). In contrast to belief-that, belief-in is not purely cognitive but has an affective component (e.g., hope or trust).

The acceptance of a proposition’s truth.

The view combining what strong foundationalists believe with the claim that non-foundational beliefs are justified only via deduction from justified foundational beliefs.

“It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.” The principle as defended by W. K. Clifford is considered an impermissivist statement of an evidentialist ethics of belief.

The study of the epistemic properties of groups and their beliefs.

An idea formed by combining multiple simple ideas or impressions. For example, the complex idea “diamond street” is formed by putting simpler ideas into relation: a street made of diamonds.

A general idea of something which allows us to recognize it as belonging to a category, distinguish it from other things, and think about it. For example, to have the concept “table” is to be able to think about tables, distinguish them from other types of furniture, and recognize tables upon encountering them.

The breaking down of a concept into more basic conceptual components, arranged to form a definition.

In a disagreement about a proposition p, a person S1 conciliates when S1 changes their attitude toward p in the direction of S2’s attitude toward p.

The view that whenever one discovers that an epistemic peer disagrees about some proposition p, one is justified in conciliating. So, for example, if S1 confidently believes p and discovers that their peer S2 believes p is false with the same degree of confidence, then S1 will be justified in decreasing their confidence about p.

Typically written in the form P(A|B), it is the probability that A obtains given that B obtains.

The process of moving from an absolute probability, such as P(A), to a conditional probability, such as P(A|B). By doing so, one “conditionalizes on B.”

A family of views about knowledge and the word “know.” According to contextualism, the standards required for you to count as knowing something vary from context to context. Contextualists often argue that skepticism is correct in some contexts but incorrect in other contexts. That is, in some contexts, the high standards required of knowledge by skeptics are appropriate, and so in those contexts we fail to know. But in other contexts, the standards required for knowledge are laxer, and there we can know many things.

When applied to claims, statements, or propositions, the term “contingent” refers to that which is possibly true and possibly false, not necessary. For example, it is a contingent truth that crows are black, since they are black but could have been white. The claim that crows are white is a contingent falsehood, since it happens to be false but could have been true.

The view that a proposition is true when it corresponds to reality and false otherwise.

Examples that refutes a claim or argument.

Degrees of belief.

A form of reasoning in which the truth of the premises logically guarantees the truth of the conclusion.

That which cancels justification (a justification defeater) or knowledge (a knowledge defeater).

A degree of confidence (or credence) that a person places in the truth of a proposition.

The belief that the corresponding proposition is false.

People in positions of relatively high social power and privilege in relation to knowledge. Dominantly situated knowers are vulnerable to ignorance because their positions of power may make them epistemically “spoiled,” limit their knowledge, and offer limited incentive to expand their epistemic resources beyond what is designated as “mainstream.” See also gatekeepers, power-based ignorance.

Stances on the truth value of a proposition (belief, disbelief, or suspension of judgment).

The kind of responsibility someone has for what they believe.

A set of bets that, when accepted, yields a guaranteed loss.

An argument showing that rational credences must adhere to the laws of probability (based on the premise that rationality requires avoiding Dutch books).

Based on observation or experience.

The philosophical position according to which all our beliefs and knowledge are based on experience. Empiricism is opposed to rationalism.

The Greek word for “knowledge” or “understanding” from which the term “epistemology” derives.

Pertaining to knowledge.

The view that the aim of democracy is (in part) to favor a true outcome (with voting answering a question such as, “which candidate is best to lead?”).

Wrongdoing related to knowledge. This includes individual interpersonal interactions that demonstrate injustice, as well as larger structures of inequity in knowledge distribution or knowledge production sustained in institutions such as the legal system, medicine, and education.

The kind of justification necessary for knowledge, requiring good epistemic reasons.

Any kind of luck that positively or negatively affects one’s epistemic status.

Any practice that interferes with the inquiry of some or all persons, without their consent/consultation, for their own purported epistemic health or improvement.

Epistemic peers with respect to a proposition p are equally likely to believe the truth about p (i.e., each is just as unbiased, intelligent, sober, well-informed, etc.).

Truth-indicative reasons—the kind necessary for epistemic justification.

An axiological thesis that denies the T-monist claim that the natural aim of belief is truth. To the pluralist, finding no straightforward hierarchy among epistemic goods suggests an un-unified order of values or even an array of epistemic goods.

The study of the aims of cognition, and the value of epistemic states (knowledge, understanding, belief, suspension, etc.) and standings (justified, unjustified, etc.).

Ways of knowing that resist the exclusive dominance of “mainstream” epistemologies and the unjust social power dynamics that those epistemologies tend to reflect and reinforce. Instead, epistemologies of resistance are structured to meet epistemic needs of marginalized people. They include but are not limited to feminist epistemologies.

The branch of philosophy traditionally defined as the study of knowledge. However, many epistemologists gradually deemphasized or abandoned the study of knowledge per se, focusing instead on other topics that nevertheless pertain to knowledge, even if only in some loose or indirect way. Expanding the traditional definition to accommodate this shift, epistemology can be understood as the study of the epistemic.

The philosophical project of providing guidance for morally and intellectually responsible doxa (belief, opinion), including how one should respond to recognized peer disagreement.

The information available to a person (an “indication of truth to a person”).

Roughly, the principle that, whenever some person S1 has some evidence that S2 has some evidence in support of p, then S1 has some evidence in support of p.

Epistemologists who think that justification is entirely a matter of a person’s evidence.

René Descartes’s methodological supposal that a powerful evil demon is deceiving one as much as it is possible for one to be deceived.

Epistemologists who think justification is a matter of which propositions provide the best explanations for a person.

A feature of a hypothesis that improves its quality as an explanation of the available data (other things being equal). An example of such a feature is simplicity, according to Ockham’s razor. By contrast, an explanatory vice is a feature of a hypothesis that reduces its quality as an explanation (other things being equal). If simplicity is an explanatory virtue, then unnecessary complexity in a hypothesis is the corresponding explanatory vice.

Objects in the external world, the world external to our minds.

The world external to our minds, containing external objects.

A variety of skepticism that denies we can have knowledge of objects that exist independently of our experiences of them. An external-world skeptic may gladly admit that you know, for example, that you are having an experience of a dog, but will deny that you can know on that basis that the dog actually exists. A stock-in-trade argument for this type of skepticism uses carefully crafted skeptical hypotheses as a means of undercutting what you take yourself to know on the basis of experience.

The view that justification is contingent on features of a person’s mind plus features external to a person’s mind.

That which entails the truth of its propositional object.

The view that justification does not entail truth.

The view that knowledge-level justification (the level required for knowledge, which is perhaps more stringent than ordinary justification) does not entail truth.

An umbrella of epistemologies that value plurality, encompassing a wide variety of ideas about knowledge including several recurrent themes: situated knowledge, standpoint, lived experience, the collaborative construction of knowledge, the bearing of power on knowledge, and the responsibilities that come with knowledge. Topics in feminist epistemologies commonly intersect with other significant conversations in epistemology, such as queer epistemologies, trans epistemologies, crip (disability) epistemologies, Indigenous epistemologies, religion-specific epistemologies, critical race epistemologies, and postcolonial epistemologies.

The law of probability stating that if two probabilities, P(A) and P(B), are mutually exclusive, the probability that either A or B obtains is the sum of their individual probabilities: P(A or B) = P(A) + P(B). In other words, P(A or B) is “additive.”

The branch of epistemology that utilizes formal methods, such as logic, set theory, and probability.

The “turn,” or major shift, among many epistemologists toward the use of “formal” methods (borrowed from linguistics, logic, and mathematics) in an effort to make the field more rigorous.

A belief that is not formed on the basis of any other belief(s).

Epistemologists who think justification has a structure consisting of justified foundational (a.k.a. basic) beliefs that serve as the epistemic foundation for any justified non-basic beliefs.

Systematically undermining someone’s confidence in their own credibility by denying or minimizing their memories, feelings, or perceptions.

People who have power to define what “counts” as valid knowledge. This might include defining the “core curriculum,” determining what is a “reliable” source, or affirming which texts are “classics” in a field. In academic life, this might include professors, librarians, and publishers. See also dominantly situated knowers, power-based ignorance.

The problem for process reliabilism of specifying the relevant process type for any given belief so that its justificatory status can be assessed.

Cases of the sort made famous by epistemologist Edmund Gettier. Such a case occurs when an element of bad epistemic luck is canceled by good epistemic luck, so that it is a justified true belief but not knowledge.

The problem of how to handle Gettier cases in the analysis of knowledge.

The denial that we have any knowledge, including the denial that we can know that skepticism is true.

The kind of knowledge that requires more than mere correct opinion.

A gap in the resources for understanding, defining, or organizing knowledge provided by a particular hermeneutic.

A type of epistemic injustice related to how knowledge is constructed. These injustices may relate to structures or frameworks for understanding that leave out or “sideline” some experiences while centering others. These might also relate to access (or limits on access) to resources for knowledge and information. A central question to ask related to hermeneutical injustice is: Whose realities do the available resources for understanding (hermeneutical resources) reflect—and whose realities do they sideline or ignore? See also epistemic injustice, hermeneutics.

The process of understanding and being understood; it’s how you turn the “raw data” of information into knowledge that has meaning.

A mental representation, including individual concepts (such as the concepts “fire” and “hot”) and the thoughts constructed therefrom (such as “the fire is hot”).

Impermissivism is closely associated with the broad application of the rational uniqueness principle (RU) and permissivism with the rejection of this principle. (RU) holds that for a given set of evidence E and a proposition p, only one doxastic attitude about p is rational. Rational agents who share that evidence will hold this single attitude, and none other. The issues which divide impermissivists and permissivists are further complicated if belief is understood in terms of degreed credences. The debate is also complicated by questions concerning the legitimacy of “faith-based” belief as indicating something quite different from everyday belief, or belief based upon inference from sufficient evidence. Clifford’s principle is associated with impermissivism and with an evidentialist ethics of belief, while James defends a (risk-limited) permissivism.

A form of reasoning in which the truth of the premises makes probable the truth of the conclusion.

An objection to (testimonial) reductionism. If reductionism is true, then young children are too cognitively unsophisticated to have testimonially justified beliefs. But it is obvious that young children have testimonially justified beliefs. Thus, reductionism is false.

Given that all else is equal, one should choose the hypothesis that best explains the evidence. One form of this can be justified by a comparative use of Bayes’s theorem. It is closely related to Ockham’s razor.

The view that every justified belief is justified by an infinite number of appropriately structured, available reasons.

The philosophical position, held by many rationalists, according to which we have certain ideas in our minds from birth, ideas which can be realized through reason.

A good intellectual trait, such as open-mindedness, intellectual humility, intellectual honesty, curiosity, or understanding.

The view that contributing factors to justification are entirely internal to a person’s mind.

The capacity to look inward to directly comprehend intellectual objects and recognize certain truths.

A device that helps bring out or strengthen an intuition.

The view that knowledge is justified true belief—a modern interpretation of Plato’s view.

The view that knowledge is justified true belief plus some fourth condition to rule out Gettier cases (and perhaps lottery cases).

A good reason for belief.

Something that prevents the satisfaction of what would otherwise (were there no defeater) satisfy an epistemic theory’s justification condition.

The view that knowledge is conceptually basic (and hence the starting point for epistemological theorizing), usually in conjunction with the claim that knowledge is of primary epistemic value (rather than, say, justification or warrant).

True belief.

Typically written as P(E|H) in Bayes’s theorem, it measures the degree to which hypothesis H predicts or explains the evidence E. It is sometimes referred to as the “explanatory power” of H with respect to E.

The thesis, named after John Locke, which relates the all-or-nothing rationality of traditional epistemology to the degreed framework as follows: a belief is rational when the rational degree of belief is sufficiently high (i.e., above some specific threshold level).

Speech that is not strictly true (e.g., figurative, hyperbolic, approximate, or elliptical speech).

Cases in which a justified belief is true on probabilistic grounds (often thought to be a counterexample to the JTB analysis).

The problem of how to handle lottery cases in the theory of knowledge.

One of the two divisions of human understanding made by David Hume. Our knowledge of matters of fact comes from observation or generalization from experiences. In other words, it is a posteriori. Because such truths are contingent, they are merely probable rather than certain.

Ignorance of one's own ignorance.

Foundationalists who think that justified basic beliefs include any beliefs that are (a) believed immediately upon having a non-doxastic experience and (b) are proper epistemic responses to experience.

A family of responses to epistemological skepticism in the tradition of G. E. Moore, based on his influential commonsense approach to philosophical problems.

When applied to claims, statements, or propositions, the term “necessary” refers to that which must be true. In other words, it is impossible for a necessary truth to be false. For example, it is a necessary truth that a triangle has three sides, which means that it is impossible for a triangle to have any other number of sides. The opposite of necessity is contingency.

A condition in a theory of justification stating that, for a belief to be justified, there must be no defeater.

A belief that is formed on the basis of at least one foundational (basic) belief.

A belief that is formed on the basis of at least one foundational (basic) belief.

The view that sometimes someone S is justified in believing some testimony p, but S lacks testimony-independent evidence that the testimony is reliable.

A normative task does not aim at description or causal explanation, but rather at assessment or guidance of some kind, according to values (norms) deemed pertinent to some practice (the value of art or particular artworks, for example), or the domain of discourse (ethics, politics, economics, epistemics, aesthetics, etc.).

An objection to (testimonial) reductionism. If reductionism is true, then, in order to avoid testimonial skepticism, we must have enough testimony-independent evidence to justify many of our testimonial beliefs. But we don’t have enough evidence and we know testimonial skepticism is false. Thus, reductionism is false.

A version of Bayesianism that requires credences to be represented and governed by objective probabilities.

The kind of probability grounded in features of the real, mind-independent world.

The methodological principle which maintains that given two competing hypotheses, the simpler hypothesis is the more probable (all else being equal). As the “razor” suggests, we should “shave off” any unnecessary elements in an explanation (“Entities should not be multiplied beyond necessity”). The principle is named after the medieval Christian philosopher/theologian William of Ockham (ca. 1285–1347). Other names for the principle include “the principle of simplicity,” “the principle of parsimony,” and “the principle of lightness” (as it is known in Indian philosophy).

A common dictum in philosophy asserting that control (“can”) is a precondition of responsibility (“ought”). This is well accepted with respect to moral responsibility: one is morally responsible for only what is within one’s control. The dictum is somewhat more controversial in the case of doxastic responsibility—one point of contention in debates over the ethics of belief.

That which is immediately or directly presented to one’s awareness in perceptual experience (prior to attaching meaning or applying a concept in apperception).

Impermissivism is closely associated with the broad application of the rational uniqueness principle (RU) and permissivism with the rejection of this principle. (RU) holds that for a given set of evidence E and a proposition p, only one doxastic attitude about p is rational. Rational agents who share that evidence will hold this single attitude, and none other. The issues which divide impermissivists and permissivists are further complicated if belief is understood in terms of degreed credences. The debate is also complicated by questions concerning the legitimacy of “faith-based” belief as indicating something quite different from everyday belief, or belief based upon inference from sufficient evidence. Clifford’s principle is associated with impermissivism and with an evidentialist ethics of belief, while James defends a (risk-limited) permissivism.

Knowledge of what it’s like to have a given experience.

Typically written as P(H|E) in Bayes’s theorem, it is the result of conditionalizing a hypothesis H on an incoming piece of evidence E, read as “the probability of the hypothesis given the evidence.”

An umbrella term for forms of ignorance connected to social power. These may include (but are not limited to) White ignorance, male ignorance, straight ignorance, cisgender ignorance, rich ignorance, and abled ignorance.

The kind of justification provided by good pragmatic reasons.

Practical benefits of belief or action.

Whatever is good enough, absent a defeater, to yield ultima facie justification (justification all things epistemically considered).

Typically written as P(H) in Bayes’s theorem, it is the probability of a hypothesis H before conditionalization on evidence. Bayesians take prior probabilities, or priors, to represent one’s initial degree of belief in H.

The view that credences should conform to the laws of probability.

An objection to probabilism, according to which adherence to the laws of probability would require logical omniscience (knowledge of, or at least justified belief in, all logically necessary truths).

The objection that subjective Bayesianism places no rational constraint on priors (prior probabilities).

Knowledge-how.

The view that justified beliefs are beliefs produced by a reliable process type.

The view that justification is a matter of having one’s beliefs produced by a properly functioning, reliable, truth-aimed cognitive system.

The requirement that a belief be formed or held in the right way for the right reasons.

A statement or claim—something which has a truth value (i.e., is either true or false).

Knowledge-that (where the that-clause expresses a proposition).

The kind of justification provided by good pragmatic reasons.

Practical benefits of belief or action.

The view that justification has a weblike structure such that any justified belief is justified by coherence relations it bears to the person’s entire set of beliefs.

Pertaining to reasons.

The principle that a body of evidence can support a range of attitudes toward a given proposition. RP denies rational uniqueness (RU).

The principle that a body of evidence supports at most one attitude toward any proposition. RU denies rational permissivism (RP).

The philosophical position that regards reason, as opposed to sense experience, as the primary source of knowledge. Rationalism is opposed to empiricism.

A good reason to think that a proposition is false, thereby providing a defeater for one’s prima facie justification for believing the proposition.

The view that some person S1 is justified in believing some S2’s testimony that p, if and only if, (a) S1 receives S2’s testimony that p, (b) S1 has inductive evidence based on observation that S2’s testimony that p is reliable, and (c) p is not defeated by other evidence S1 has.

The set of all possible outcomes relevant to determining a given objective probability. One calculates the probability of an event or proposition X by dividing the number of possible ways in which X can obtain by the size of the reference class.

The problem of determining a reference class in cases where there is no clear choice.

An argument put forward by the first-century Pyrrhonist philosopher Agrippa for global skepticism about justification (and hence knowledge). This argument begins with the observation that, for a belief B to be justified, the chain of reasons ultimately leading to B must have one of three possible structures: the chain is either (a) finite and linear, (b) circular, or (c) infinite. The next step is to argue that each possible structure is problematic, then draw the conclusion that there is no possible way for a belief to be justified.

One of the two divisions of human understanding made by David Hume. Relations of ideas concern matters like logic and mathematics. Relations of ideas do not depend on how the world actually is. They are known a priori. Truths generated by relations of ideas are certain (not merely probable), true by definition, and therefore impossible to contradict.

A rule that, according to David Lewis, governs conversations. This rule requires that participants in a conversation not ignore possibilities believed true by one of the participants. When deciding whether to count someone as knowing something, the rule of belief forbids you from ignoring possibilities believed by conversational partners that would undermine that person’s counting as knowing. The rule of belief typically expands the alternatives that must be ruled out in a conversation if we are to ascribe knowledge to someone in that context.

The rule that one’s prior probability must be updated in light of new evidence by conditionalizing on that evidence (via Bayes’s theorem, according to Bayesians).

In probability theory, it is the total set of possible simple outcomes for an event. A reference class consists in subsets of the sample space.

Ideas that contain a single element, such as a patch of brown or the idea of red. Simple ideas are basic and indivisible as opposed to complex ideas.

All knowledge is “situated” in relation to a knower’s point of view (see also standpoint). In effect, there is no “view from nowhere”—all knowledge is “situated knowledge.”

An imaginary scenario such that no set of experiences can distinguish between this scenario happening and life as we ordinarily take it to be happening. If all my life has been a perfectly coherent dream, then nothing in my experiences will show me that it has been a dream. External-world skeptics often argue that since we cannot eliminate skeptical hypotheses, we cannot know that any objects exist beyond our experiences of them.

In the context of this book, skepticism is an epistemological thesis, specifically the denial that anyone has knowledge about some type of claim or other. Skeptics in philosophy may focus on some narrow range of claims, denying that we have knowledge about, for example, the external world, morality, free will, the future, or God’s existence, and yet allow that we know many other things. They may also deny that we have any knowledge (global skepticism). (Another prominent form of epistemological skepticism is skepticism about epistemic justification, which is sometimes the basis for skepticism about knowledge, given the standard view that knowledge requires justification.)

The study of how social relationships and interactions affect the epistemic properties of individuals and groups.

The “turn,” or major shift, among many epistemologists toward an emphasis on the social dimensions of knowledge (and of the epistemic more broadly).

A knower’s point of view, including their social identities (gender, race, class, age, etc.) and life experiences. Recognizing standpoint is key to understanding how knowledge is situated.

The view that sometimes, when one finds out that a peer disagrees, one is justified in retaining one’s original doxastic attitude.

Foundationalists who think that justified basic beliefs include only those basic beliefs in propositions about which we are infallible.

A version of Bayesianism that allows credences to be represented and governed by subjective probabilities.

Probabilities that are grounded in a person’s degrees of confidence in propositions.

Remaining neutral about whether or not a proposition is true, neither believing nor disbelieving the proposition.

The view that knowledge is sufficiently warranted true belief.

A truth expressed by a sentence in which the predicate term is neither contained in, nor is the meaning of, the subject term; the predicate adds some new information about the subject. That is, synthetic truths are not true by definition; therefore, they can be denied without contradiction.

The axiological thesis that the natural goal or aim of belief is truth, and that epistemic value is rooted in holding true beliefs and avoiding false beliefs. The value of truth is not grounded in knowledge or anything else.

A Latin term meaning “blank tablet” or “blank slate.” Empiricists like John Locke argue that the human mind is like a tabula rasa at the time of birth, and that the mind acquires knowledge through sense experience and from its ability to reflect upon its own internal operations.

The view that knowledge is true belief plus some third condition, often called “warrant” (or more accurately, “sufficient warrant,” to allow that some minimum degree of warrant may be needed for knowledge). So, the view that knowledge is sufficiently warranted true belief, or sWTB, is an example of a TB+ account (where sW fills in the +). The traditional JTB analysis is another example (where J fills in the +). A JTB+ account is a third (where J partially fills in the original +, with some still-unspecified remainder represented by a new +). (Note the possibility that an sWTB account is also a JTB+ account—but only if sW = J+. Those who prefer to theorize in terms of “warrant” often reject that equation, and sometimes reject the justification requirement on knowledge altogether.)

A type of epistemic injustice specifically related to how knowledge is received. Who is believed as a reliable source of knowledge? Whose statements are taken seriously? Issues of credibility and legitimacy are central in testimonial injustice.

Any utterance (e.g., speaking, writing, signing, etc.) by which the actor intends to communicate that proposition p is true.

The view that knowledge is justified true belief—a modern interpretation of Plato’s view.

Kant’s term for that which is presupposed in, and is necessary for, experience; something a priori that makes experience possible.

Kant’s synthesis of rationalism and empiricism utilizing a transcendental bridge between the mind and the world, making possible synthetic a priori knowledge. The term “idealism,” when not preceded by “transcendental,” may refer to the theories of Berkeley or Hegel, both of which should be distinguished from Kant’s view.

The axiological thesis that the natural goal or aim of belief is truth, and that epistemic value is rooted in holding true beliefs and avoiding false beliefs. The value of truth is not grounded in knowledge or anything else.

One of two possible values that a given proposition can take with respect to whether or not it is true. “True” is one possible truth value; “false” is the other. (Note that this assumes the standard or “classical” commitment to the principle of “bivalence,” according to which there are exactly two possible truth values. Some “non-classical” views reject bivalence by maintaining, for example, that there are additional, intermediate truth values, such as “half-true,” “mostly true,” or “mostly false.”)

Justification all things epistemically considered (equivalently, prima facie justification absent a defeater).

A good reason to think that the source of a belief is not good enough for ultima facie justification, thereby defeating one’s prima facie justification for the belief.

The problem, at base, of why we hold a person’s having knowledge to be more valuable than their having (mere) true belief. The problem, introduced here with Plato’s Meno, is broken down into several sub-problems by some contemporary epistemologists.

The “turn,” or major shift, among many epistemologists toward an emphasis on the study of epistemic value and its relationship to value in other domains (e.g., practical, aesthetic, and moral).

Knowledge-precluding luck.

The axiological thesis that the natural goal or aim of belief is truth, and that epistemic value is rooted in holding true beliefs and avoiding false beliefs. The value of truth is not grounded in knowledge or anything else.

Complementary to (if not simply part of) the better-known trend of virtue epistemology, vice epistemology is the philosophical study of the nature, identity, and epistemological significance of intellectual vices.

The philosophical study of the nature, identity, and epistemological significance of intellectual virtues. The term covers a range of recent approaches that grant characterological concepts (including specific habits, dispositions, or strategies which constitute excellences or “virtues” for agents engaged in inquiry) an important or even fundamental role in epistemology.

The view that epistemically justified beliefs just are those resulting from intellectually virtuous character traits.

That which when added (in sufficient degree) to true belief yields knowledge.

Remaining neutral about whether or not a proposition is true, neither believing nor disbelieving the proposition.