We often believe what we are told by our parents, friends, doctors, and news reporters. We often believe what we see, taste, and smell. We hold beliefs about the past, the present, and the future. Do we have a right to hold any of these beliefs? Are any supported by evidence? Should we continue to hold them, or should we discard some? These questions are evaluative. They ask whether our beliefs meet a standard that renders them fitting, right, or reasonable for us to hold. One prominent standard is epistemic justification.
Very generally, justification is the right standing of an action, person, or attitude with respect to some standard of evaluation. For example, a person’s actions might be justified under the law, or a person might be justified before God.
Epistemic justification (from episteme, the Greek word for knowledge) is the right standing of a person’s beliefs with respect to knowledge, though there is some disagreement about what that means precisely. Some argue that right standing refers to whether the beliefs are more likely to be true. Others argue that it refers to whether they are more likely to be knowledge. Still others argue that it refers to whether those beliefs were formed or are held in a responsible or virtuous manner.
Because of its evaluative role, justification is often used synonymously with rationality. There are, however, many types of rationality, some of which are not about a belief’s epistemic status and some of which are not about beliefs at all. So, while it is intuitive to say a justified belief is a rational belief, it is also intuitive to say that a person is rational for holding a justified belief. This article focuses on theories of epistemic justification and sets aside their relationship to rationality.
In addition to being an evaluative concept, many philosophers hold that justification is normative. Having justified beliefs is better, in some sense, than having unjustified beliefs, and determining whether a belief is justified tells us whether we should, should not, or may believe a proposition. But this normative role is controversial, and some philosophers have rejected it for a more naturalistic, or science-based, role. Naturalistic theories focus less on belief-forming decisions—decisions from a subject’s own perspective—and more on describing, from an objective point of view, the relationship between belief-forming mechanisms and reality.
Regardless of whether justification refers to right belief or responsible belief, or whether it plays a normative or naturalistic role, it is still predominantly regarded as essential for knowledge.
Consider your simplest, most obvious beliefs: the color of the sky, the date of your birth, what chocolate tastes like. Are these beliefs justified for you? What would explain the rightness or fittingness of these beliefs? One prominent account of justification is that a belief is justified for a person only if she has a good reason for holding it. If you were to ask me why I believe the sky is blue and I were to answer that I am just guessing or that my horoscope told me, you would likely not consider either a good reason. In either case, I am not justified in believing the sky is blue, even if it really is blue. However, if I were to say, instead, that I remember seeing the sky as blue or that I am currently seeing that it is blue, you would likely think better of my reason. So, having good reasons is a very natural explanation of how our beliefs are justified.
Further, the possibility that my belief that the sky is blue is not justified, even if it is true that the sky is blue, suggests that justification is more than simply having a true belief. All of my beliefs may be true, but if I obtained them accidentally or by faulty reasoning, then they are not justified for me; if I am seeking knowledge, I have no right to hold them. Further still, true belief may not even be necessary for justification. If I understand Newtonian physics, and if Newton’s arguments seem right to me, and if all contemporary physicists testify that Newtonian physics is true, it is plausible to think that my belief that it is true is justified, even if Einstein will eventually show that Newton and I are wrong. We can imagine this was the situation of many physicists in the late 1700s. If this is right, justification is fallible—it is possible to be justified in believing false propositions. Though some philosophers have, in the past, rejected fallibilism about justification, it is now widely accepted. Having good reasons, it turns out, does not guarantee having true beliefs.
But the idea that justification is a matter of having good reasons faces a serious obstacle. Normally, when we give reasons for a belief, we cite other beliefs. Take, for example, the proposition, “The cat is on the mat.” If you believe it and are asked why, you might offer the following beliefs to support it:
1. I see that the cat is on the mat.
2. Seeing that X implies that X.
Together, these seem to constitute a good reason for believing the proposition:
3. The cat is on the mat.
But does this mean that proposition 3 is epistemically justified for you? Even if the combination of propositions 1 and 2 counts as a good reason to believe 3, proposition 3 is not justified unless both 1 and 2 are also justified. Do we have good reasons for believing 1 and 2? If not, then according to the good reasons account of justification, propositions 1 and 2 are unjustified, which means that 3 is unjustified. If we do have good reasons for believing 1 and 2, do we have good reasons for believing those propositions? How long does our chain of good reasons have to be before even one belief is justified? These questions lead to a classic dilemma.
a. The Dilemma of Inferential Justification
For simplicity, let’s focus on proposition 1: I see that the cat is on the mat.
Horn A: If there are no good reasons to believe proposition 1, then proposition 1 is unjustified, which means 3 is unjustified.
Horn B: If there is a good reason to believe proposition 1, say proposition 1a, then either 1a is unjustified or we need another belief, proposition 1b, to justify 1a. If this process continues infinitely, then 1 is ultimately unjustified, and, therefore, 3 is unjustified.
Either way, proposition 3 is unjustified.
Horn A of the dilemma is the problem of skepticism about justification. If our most obvious beliefs are unjustified, then no belief derived from them is justified; and if no belief is justified, we are left with an extreme form of skepticism. Horn B of the dilemma is called the regress problem. If every reason we offer requires a reason that also requires a reason, and so on, infinitely, then no belief is ultimately justified.
Both of these problems assume that all justification involves inferring beliefs from one or more other beliefs, so let’s call these two problems the dilemma of inferential justification (DIJ). And let’s call the assumption that all justification involves inference from other beliefs the inferential assumption (also called the doxastic assumption, Pollock 1986: 19).
Responses to this dilemma typically take one of two forms. On one hand, we might embrace Horn A, which is, in effect, to adopt skepticism and eschew any further attempts to justify our beliefs. This is the classic route of the Pyrrhonian skeptics, such as Sextus Empiricus, and some later Academic skeptics, such as Arcesilaus. (For more on these views, see Ancient Greek Skepticism.)
On the other hand, we might offer an explanation of how beliefs can be justified in spite of the dilemma. In other words, we might offer an account of epistemic justification that resolves the dilemma, either by constructing a third, less problematic option or by showing that Horn B is not as troublesome as philosophers have traditionally supposed. This non-skeptical route is the majority position and the focus of the remainder of this article.
Philosophers tend to agree that any adequate account of epistemic justification—that is, an account that resolves the dilemma—must do at least three things: (1) explain how a belief comes to be justified for a person, (2) explain what role justification plays in our belief systems, and (3) explain what makes justification valuable in a way that is not merely practically or aesthetically valuable.
b. Explaining How Beliefs are Justified
One of the central aims of theories of epistemic justification is to explain how a person’s beliefs come to be justified in a way that resolves the DIJ. Those who accept the inferential assumption argue either that a belief is justified if it coheres with—that is, stands in mutual support with—the whole set of a person’s beliefs (coherentism) or that an infinite chain of sequentially supported beliefs is not as problematic as philosophers have claimed (infinitism).
Among those who reject the inferential assumption, some argue that justification is grounded in special beliefs, called basic beliefs, that are either obviously true or supported by non-belief states, such as perceptions (foundationalism). Others who reject the inferential assumption argue that justification is either a function of the quality of the mechanisms by which beliefs are formed (externalism) or at least partly a function of certain qualities or virtues of the believer (virtue epistemology).
In addition to resolving the DIJ, theories of justification must explain what it is about forming or holding a belief that justifies it in order to explain how a belief is justified. Some argue that justification is a matter of a person’s mental states: a belief is justified only if a person has conscious access to beliefs and evidence that support it (internalism). Others argue that justification is a matter of a belief’s origin or the mechanisms that produce it: a belief is justified only if it was formed in a way that makes the belief likely to be true (externalism), whether through an appropriate connection with the state of affairs the belief is about or through reliable processes. The former view is called internalism because the justifying reasons—whether beliefs, experiences, testimony, and so forth—are internal mental states, that is, states consciously available to a person. The latter view is called externalism because the justifying states are outside a person’s immediate mental access; they are relationships between a person’s belief states and the states of the world outside the believer’s mental states (see Internalism and Externalism in Epistemology).
c. Explaining the Role of Justification
A second central aim of epistemology is to identify and explain the role that justification plays in our belief-forming behavior. Some argue that justification is required for the practical work of having responsible beliefs. Having certain reasons makes it possible for us to choose well which beliefs to form and hold and which to reject. This is called the guidance model of justification. Some philosophers who accept the guidance model, like René Descartes and W. K. Clifford, pair it with a strongly normative role according to which justification is a matter of fulfilling epistemic obligations. This combination is sometimes called the guidance-deontological model of justification, where “deontology” refers to one’s duties with respect to believing. Other epistemologists reject the guidance and guidance-deontological models for more descriptive models. Justification, according to these philosophers, is simply a feature of our psychology, and though our minds form beliefs more effectively under some circumstances than others, the conditions necessary for forming justified beliefs are outside of our access and control. This objective, naturalistic model of justification has it that our understanding of justification should be informed, in large part, by psychology and cognitive science.
d. Explaining Why Justification is Valuable
A third central aim of theories of justification is to explain why justification is epistemically valuable. Some epistemologists argue that justification is crucial for avoiding error and increasing our store of knowledge. Others argue that knowledge is more complicated than attaining true beliefs in the right way and that part of the value of knowledge is that it makes the knower better off. These philosophers are less interested in the truth-goal in its unqualified sense; they are more interested in intellectual virtues that position a person to be a proficient knower, virtues such as intellectual courage and honesty, openness to new evidence, creativity, and humility. Though justification increases the likelihood of knowledge under some circumstances, we may rarely be in those circumstances or may be unable to recognize when we are; nevertheless, these philosophers suggest, there is a fitting way of believing regardless of whether we are in those circumstances.
A minority of epistemologists reject any connection between justification and knowledge or virtue. Instead, they focus either on whether a belief fits into an objective theory about the world or whether a belief is useful for attaining our many and diverse cognitive goals. An example of the former involves focusing solely on the causal relationship between a person’s beliefs and the world; if knowledge is produced directly by the world, the concept of justification drops out (for example, Alvin Goldman, 1967). Other philosophers, whom we might call relativists and pragmatists, argue that epistemic value is best explained in terms of what most concerns us in practice.
Debates surrounding these three primary aims inspire many others. There are questions about the sources of justification: Is all evidence experiential, or is some non-experiential? Are memory and testimony reliable sources of evidence? And there are additional questions about how justification is established and overturned: How strong does a reason have to be before a belief is justified? What sort of contrary, or defeating, reasons can overturn a belief’s justification? In what follows, we look at the strengths and weaknesses of prominent theories of justification in light of the three aims just outlined, leaving these secondary questions to more detailed studies.
e. Justification and Knowledge
The type of knowledge primarily at issue in discussions of justification is knowledge that a proposition is true, or propositional knowledge. Propositional knowledge stands in contrast with knowledge of how to do something, or practical knowledge. (For more on this distinction, see Knowledge.) Traditionally, three conditions must be met in order for a person to know a proposition—say, “The cat is on the mat.”
First, the proposition must be true; there must actually be a state of affairs expressed by the proposition in order for the proposition to be known. Second, that person must believe the proposition, that is, she must mentally assent to its truth. And third, her belief that the proposition is true must be justified for her. Knowledge, according to this traditional account, is justified true belief (JTB). And though philosophers still largely accept that justification is necessary for knowledge, it turns out to be difficult to explain precisely how justification contributes to knowing.
Historically, philosophers regarded the relationship between justification and knowledge as strong. In Plato’s Meno, Socrates suggests that justification “tethers” true belief “with chains of reasons why” (97A-98A, trans. Holbo and Waring, 2002). This idea of tethering came to mean that justification—when one is genuinely justified—guarantees or significantly increases the likelihood that a belief is true, and, therefore, we can tell directly when we know a proposition. But a series of articles in the 1960s and 1970s demonstrated that this strong view is mistaken; justification, even for true beliefs, can be a matter of luck. For example, imagine the following three things are truth: (1) it is three o’clock, (2) the normally reliable clock on the wall reads three o’clock, and (3) you believe it is three o’clock because the clock on the wall says so. But if the clock is broken, even though you are justified in believing it is three o’clock, you are not justified in a way that constitutes knowledge. You got lucky; you looked at the clock at precisely the time it corresponded with reality, but its correspondence was not due to the clock’s reliability. Therefore, your justified true belief seems not to be an instance of knowledge. This sort of example is characteristic of what I call the Gettier Era (§6). During the Gettier Era, philosophers were pressed to revise or reject the traditional relationship.
In response, some have maintained that the relationship between justification and knowledge is strong, but they modify the concept justification in attempt to avoid lucky true beliefs. Others argue that the relationship is weaker than traditionally supposed—something is needed to increase the likelihood that a belief is knowledge, and justification is part of that, but justification is primarily about responsible belief. Still others argue that whether we can tell we are justified is irrelevant; justification is a truth-conducive relationship between our beliefs and the world, and we need not be able to tell, at least not directly, whether we are justified. The Gettier Era (§6) precipitated a number of changes in the conversation about justification’s relationship to knowledge, and these remain important to contemporary discussions of justification.