Epistemology
Overview
 
Epistemology is the branch of philosophy
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

 concerned with the nature and scope (limitations) of knowledge
Knowledge
Knowledge is a familiarity with someone or something unknown, which can include information, facts, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject...

. It addresses the questions:
  • What is knowledge?
  • How is knowledge acquired?
  • How do we know what we know?


Much of the debate in this field has focused on analyzing
Philosophical analysis
Philosophical analysis is a general term for techniques typically used by philosophers in the analytic tradition that involve "breaking down" philosophical issues. Arguably the most prominent of these techniques is the analysis of concepts...

 the nature of knowledge and how it relates to connected notions such as truth
Truth
Truth has a variety of meanings, such as the state of being in accord with fact or reality. It can also mean having fidelity to an original or to a standard or ideal. In a common usage, it also means constancy or sincerity in action or character...

, belief
Belief
Belief is the psychological state in which an individual holds a proposition or premise to be true.-Belief, knowledge and epistemology:The terms belief and knowledge are used differently in philosophy....

, and justification
Theory of justification
Theory of justification is a part of epistemology that attempts to understand the justification of propositions and beliefs. Epistemologists are concerned with various epistemic features of belief, which include the ideas of justification, warrant, rationality, and probability...

. It also deals with the means of production of knowledge, as well as skepticism about different knowledge claims.

The term was introduced by the Scottish philosopher James Frederick Ferrier
James Frederick Ferrier
James Frederick Ferrier was a Scottish metaphysical writer. He introduced the term epistemology.-Education and early writings:Ferrier was born in Edinburgh, the son of John Ferrier, writer to the signet...

 (1808–1864).

In physics, the concept of epistemology is vital in the modern interpretation of quantum mechanics , and is used by many authors to analyse the works of dominant physicists such as Werner Heisenberg
Werner Heisenberg
Werner Karl Heisenberg was a German theoretical physicist who made foundational contributions to quantum mechanics and is best known for asserting the uncertainty principle of quantum theory...

, Niels Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...

, Max Born
Max Born
Max Born was a German-born physicist and mathematician who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics and supervised the work of a number of notable physicists in the 1920s and 30s...

 and Wolfgang Pauli
Wolfgang Pauli
Wolfgang Ernst Pauli was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after being nominated by Albert Einstein, he received the Nobel Prize in Physics for his "decisive contribution through his discovery of a new law of Nature, the exclusion principle or...

.

In philosophy, epistemology refers to the study of the nature, origin, and limits of human knowledge.
Encyclopedia
Epistemology is the branch of philosophy
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

 concerned with the nature and scope (limitations) of knowledge
Knowledge
Knowledge is a familiarity with someone or something unknown, which can include information, facts, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject...

. It addresses the questions:
  • What is knowledge?
  • How is knowledge acquired?
  • How do we know what we know?


Much of the debate in this field has focused on analyzing
Philosophical analysis
Philosophical analysis is a general term for techniques typically used by philosophers in the analytic tradition that involve "breaking down" philosophical issues. Arguably the most prominent of these techniques is the analysis of concepts...

 the nature of knowledge and how it relates to connected notions such as truth
Truth
Truth has a variety of meanings, such as the state of being in accord with fact or reality. It can also mean having fidelity to an original or to a standard or ideal. In a common usage, it also means constancy or sincerity in action or character...

, belief
Belief
Belief is the psychological state in which an individual holds a proposition or premise to be true.-Belief, knowledge and epistemology:The terms belief and knowledge are used differently in philosophy....

, and justification
Theory of justification
Theory of justification is a part of epistemology that attempts to understand the justification of propositions and beliefs. Epistemologists are concerned with various epistemic features of belief, which include the ideas of justification, warrant, rationality, and probability...

. It also deals with the means of production of knowledge, as well as skepticism about different knowledge claims.

The term was introduced by the Scottish philosopher James Frederick Ferrier
James Frederick Ferrier
James Frederick Ferrier was a Scottish metaphysical writer. He introduced the term epistemology.-Education and early writings:Ferrier was born in Edinburgh, the son of John Ferrier, writer to the signet...

 (1808–1864).

In physics, the concept of epistemology is vital in the modern interpretation of quantum mechanics , and is used by many authors to analyse the works of dominant physicists such as Werner Heisenberg
Werner Heisenberg
Werner Karl Heisenberg was a German theoretical physicist who made foundational contributions to quantum mechanics and is best known for asserting the uncertainty principle of quantum theory...

, Niels Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...

, Max Born
Max Born
Max Born was a German-born physicist and mathematician who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics and supervised the work of a number of notable physicists in the 1920s and 30s...

 and Wolfgang Pauli
Wolfgang Pauli
Wolfgang Ernst Pauli was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after being nominated by Albert Einstein, he received the Nobel Prize in Physics for his "decisive contribution through his discovery of a new law of Nature, the exclusion principle or...

.

In philosophy, epistemology refers to the study of the nature, origin, and limits of human knowledge. The field is sometimes referred to as the theory of knowledge. Epistemology has a long history, beginning with the ancient Greeks and continuing to the present. Epistemology (how we know things) is combined with ontology (what things exist) to constitute the branch of philosophy known as metaphysics
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...

. The other three branches of philosophy are ethics
Ethics
Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...

 (which attempts to understand and prescribe conduct), politics
Politics
Politics is a process by which groups of people make collective decisions. The term is generally applied to the art or science of running governmental or state affairs, including behavior within civil governments, but also applies to institutions, fields, and special interest groups such as the...

 (which attempts to describe how we should interact with one another), and aesthetics
Aesthetics
Aesthetics is a branch of philosophy dealing with the nature of beauty, art, and taste, and with the creation and appreciation of beauty. It is more scientifically defined as the study of sensory or sensori-emotional values, sometimes called judgments of sentiment and taste...

 (which discusses questions of beauty and taste).

Knowledge that, knowledge how, and knowledge by acquaintance

In this article, and in epistemology in general, the kind of knowledge usually discussed is propositional knowledge, also known as "knowledge that." This is distinct from "knowledge how" and "acquaintance-knowledge." For example: in mathematics, it is known that 2 + 2 = 4, but there is also knowing how to add two numbers and knowing a person (e.g., oneself), place (e.g., one's hometown), thing (e.g., cars), or activity (e.g., addition). Some (though not all) philosophers think there is an important distinction between "knowing that," "knowing how," and "acquaintance-knowledge," with epistemology primarily interested in the first.

Bertrand Russell
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...

 is famous for distinguishing "knowledge by description
Knowledge by description
The contrasting expressions "knowledge by description" and "knowledge by acquaintance" were promoted by Bertrand Russell, who was extremely critical of the equivocal nature of the word know, and believed that the equivocation arose from a failure to distinguish between the two fundamentally...

" (a form of knowledge that) and "knowledge by acquaintance
Knowledge by acquaintance
The contrasting expressions "knowledge by acquaintance" and "knowledge by description" were promoted by Bertrand Russell, who was extremely critical of the equivocal nature of the word know, and believed that the equivocation arose from a failure to distinguish between the two fundamentally...

" in Problems of Philosophy. Gilbert Ryle
Gilbert Ryle
Gilbert Ryle , was a British philosopher, a representative of the generation of British ordinary language philosophers that shared Wittgenstein's approach to philosophical problems, and is principally known for his critique of Cartesian dualism, for which he coined the phrase "the ghost in the...

 is often credited with emphasizing the distinction between knowing how and knowing that in The Concept of Mind. In Personal Knowledge, Michael Polanyi
Michael Polanyi
Michael Polanyi, FRS was a Hungarian–British polymath, who made important theoretical contributions to physical chemistry, economics, and the theory of knowledge...

 argues for the epistemological relevance of knowledge how and knowledge that; using the example of the act of balance involved in riding a bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....

, he suggests that the theoretical knowledge of the physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 involved in maintaining a state of balance cannot substitute for the practical knowledge of how to ride, and that it is important to understand how both are established and grounded. This position is essentially Ryle's, who argued that a failure to acknowledge the distinction between knowledge that and knowledge how leads to vicious regresses.

In recent times, some epistemologists (Sosa
Ernest Sosa
Ernest Sosa is an American philosopher primarily interested in epistemology. He is currently Board of Governors Professor of Philosophy at Rutgers University. He has been at Rutgers full-time since January, 2007; previously, he had been at Brown University since 1964...

, Greco
John Greco (philosopher)
John Greco is an epistemologist and holds the Leonard and Elizabeth Eslick Chair in Philosophy at Saint Louis University.-Notes:...

, Kvanvig
Jonathan Kvanvig
Jonathan Kvanvig is Distinguished Professor of Philosophy at Baylor University.Kvanvig is also an author, best known for his book The Problem of Hell which debates Hell in a modern theological and philosophical way....

, Zagzebski
Linda Trinkaus Zagzebski
Linda Trinkaus Zagzebski is an American philosopher, and is Kingfisher College Chair of Philosophy of Religion and Ethics at the University of Oklahoma. She is a 2011 Guggenheim Fellow....

) have argued that epistemology should evaluate people's properties (i.e., intellectual virtues) and not just the properties of propositions or propositional mental attitudes. One reason is that higher forms of cognitive success (i.e., understanding) are said to involve features that can't be evaluated from a justified true belief
Justified true belief
Justified true belief is one definition of knowledge that states in order to know that a given proposition is true, one must not only believe the relevant true proposition, but one must also have justification for doing so. In more formal terms, a subject S knows that a proposition P is true if,...

 view of knowledge.

Belief

Statements of "belief" sometimes mean the speaker has faith that something would prove to be useful or successful in some sense—perhaps the speaker might "believe in" his or her favourite football team. This is not the kind of belief usually addressed within epistemology. The kind dealt with is when "to believe something" simply means any cognitive content held as true. For example, to believe that the sky is blue is to think that the proposition "The sky is blue" is true, even if the sky is red.

Truth

Whether someone's belief is true is not a prerequisite for its belief. On the other hand, if something is actually known, then it categorically cannot be false. For example, a person believes that a particular bridge is safe enough to support him, and attempts to cross it; unfortunately, the bridge collapses under his weight. It could be said that he believed that the bridge was safe, but that this belief was mistaken. It would not be accurate to say that he knew that the bridge was safe, because plainly it was not. By contrast, if the bridge actually supported his weight then he might say he “thought” that the bridge was safe, and now after proving it to himself, he knows.

Epistemologists argue over whether belief is the proper truth-bearer. Some would rather describe knowledge as a system of justified true propositions, and others as a system of justified true sentences. But belief is the most commonly invoked truth bearer, since Plato
Plato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...

's day.

Justification

In many of Plato
Plato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...

's dialogues, such as the Meno
Meno
Meno is a Socratic dialogue written by Plato. It attempts to determine the definition of virtue, or arete, meaning virtue in general, rather than particular virtues, such as justice or temperance. The first part of the work is written in the Socratic dialectical style and Meno is reduced to...

, and in particular the Theaetetus
Theaetetus (dialogue)
The Theaetetus is one of Plato's dialogues concerning the nature of knowledge. The framing of the dialogue begins when Euclides tells his friend Terpsion that he had written a book many years ago based on what Socrates had told him of a conversation he'd had with Theaetetus when Theaetetus was...

, Socrates
Socrates
Socrates was a classical Greek Athenian philosopher. Credited as one of the founders of Western philosophy, he is an enigmatic figure known chiefly through the accounts of later classical writers, especially the writings of his students Plato and Xenophon, and the plays of his contemporary ...

 considers a number of theories as to what knowledge is, the last being that knowledge is true belief that has been "given an account of" — meaning explained or defined in some way. According to the theory that knowledge is justified true belief, in order to know that a given proposition is true, one must not only believe the relevant true proposition, but one must also have a good reason for doing so. One implication of this would be that no one would gain knowledge just by believing something that happened to be true. For example, an ill person with no medical training, but with a generally optimistic attitude, might believe that he will recover from his illness quickly. Nevertheless, even if this belief turned out to be true, the patient would not have known that he would get well since his belief lacked justification.
The definition of knowledge as justified true belief was widely accepted until the 1960s. At this time, a paper written by the American philosopher Edmund Gettier
Edmund Gettier
Edmund L. Gettier III is an American philosopher and Professor Emeritus at the University of Massachusetts Amherst; he owes his reputation to a single three-page paper published in 1963 called "Is Justified True Belief Knowledge?"Gettier was educated at Cornell University, where his mentors...

 provoked major widespread discussion. See theories of justification
Theory of justification
Theory of justification is a part of epistemology that attempts to understand the justification of propositions and beliefs. Epistemologists are concerned with various epistemic features of belief, which include the ideas of justification, warrant, rationality, and probability...

  for other views on the idea.

The Gettier problem

Edmund Gettier is remembered for his 1963 argument, which called into question the theory of knowledge that had been dominant among philosophers for thousands of years. In a few pages, Gettier argued that there are situations in which one's belief may be justified and true, yet fail to count as knowledge. That is, Gettier contended that while justified belief in a true proposition is necessary for that proposition to be known, it is not sufficient. As in the diagram above, a true proposition can be believed by an individual (red region) but still not fall within the "knowledge" category (yellow region).

According to Gettier, there are certain circumstances in which one does not have knowledge, even when all of the above conditions are met. Gettier proposed two thought experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...

s, which have come to be known as "Gettier cases," as counterexample
Counterexample
In logic, and especially in its applications to mathematics and philosophy, a counterexample is an exception to a proposed general rule. For example, consider the proposition "all students are lazy"....

s to the classical account of knowledge. One of the cases involves two men, Smith and Jones, who are awaiting the results of their applications for the same job. Each man has ten coins in his pocket. Smith has excellent reasons to believe that Jones will get the job and, furthermore, knows that Jones has ten coins in his pocket (he recently counted them). From this Smith infers, "the man who will get the job has ten coins in his pocket." However, Smith is unaware that he also has ten coins in his own pocket. Furthermore, Smith, not Jones, is going to get the job. While Smith has strong evidence to believe that Jones will get the job, he is wrong. Smith has a justified true belief that a man with ten coins in his pocket will get the job; however, according to Gettier, Smith does not know that a man with ten coins in his pocket will get the job, because Smith's belief is "...true by virtue of the number of coins in Jones's pocket, while Smith does not know how many coins are in Smith's pocket, and bases his belief...on a count of the coins in Jones's pocket, whom he falsely believes to be the man who will get the job." (see p. 122.) These cases fail to be knowledge because the subject's belief is justified, but only happens to be true by virtue of luck. In other words, he made the correct choice (in this case predicting an outcome) for the wrong reasons.

Responses to Gettier

The responses to Gettier have been varied. Usually, they have involved substantive attempts to provide a definition of knowledge different from the classical one, either by recasting knowledge as justified true belief with some additional fourth condition, or as something else altogether.
Infallibilism, indefeasibility

In one response to Gettier, the American philosopher Richard Kirkham
Richard Kirkham
Richard Ladd Kirkham is an American philosopher. Among his published works are the much-cited Theories of Truth , "Does the Gettier Problem Rest on a Mistake?" Mind , and "On Paradoxes and a Surprise Exam" Philosophia . Kirkham graduated from Cornell College in 1977 and received his Ph.D...

 has argued that the only definition of knowledge that could ever be immune to all counterexamples is the infallibilist
Infallibilism
Infallibilism is, in epistemology, the position that knowledge is, by definition, a true belief which cannot be rationally doubted. Other beliefs may be rationally justified, but they do not rise to the level of knowledge unless absolutely certain...

 one. To qualify as an item of knowledge, goes the theory, a belief must not only be true and justified, the justification of the belief must necessitate its truth. In other words, the justification for the belief must be infallible. (See Fallibilism, below, for more information.)

Yet another possible candidate for the fourth condition of knowledge is indefeasibility. Defeasibility theory maintains that there should be no overriding or defeating truths for the reasons that justify one's belief. For example, suppose that person S believes he saw Tom Grabit steal a book from the library and uses this to justify the claim that Tom Grabit stole a book from the library. A possible defeater or overriding proposition for such a claim could be a true proposition like, "Tom Grabit's identical twin Sam is currently in the same town as Tom." When no defeaters of one's justification exist, a subject would be epistemically justified.

The Indian philosopher B K Matilal has drawn on the Navya-Nyaya
Navya-Nyaya
The Navya-Nyāya or Neo-Logical darśana of Indian logic and Indian philosophy was founded in the 13th century CE by the philosopher Gangeśa Upādhyāya of Mithila. It was a development of the classical Nyāya darśana. Other influences on Navya-Nyāya were the work of earlier philosophers Vācaspati...

 fallibilism
Fallibilism
Fallibilism is the philosophical principle that human beings could be wrong about their beliefs, expectations, or their understanding of the world...

 tradition to respond to the Gettier problem.
Nyaya theory distinguishes between know p and know that one knows p – these are different events, with different causal conditions.
The second level is a sort of implicit inference that usually follows immediately the episode of knowing p (knowledge simpliciter). The Gettier
case is analyzed by referring to a view of Gangesha (13th c.), who takes any true belief to be knowledge; thus a true belief acquired through a wrong
route may just be regarded as knowledge simpliciter on this view.
The question of justification arises only at the second level, when one
considers the knowledgehood of the acquired belief.
Initially, there is lack of uncertainty, so it becomes a true belief.
But at the very next moment, when the hearer is about to embark upon the venture of knowing whether he knows p, doubts may arise. "If, in
some Gettier-like cases, I am wrong in my inference about the
knowledgehood of the given occurrent belief (for the evidence may be
pseudo-evidence), then I am mistaken about the truth of my belief – and
this is in accord with Nyaya fallibilism: not all knowledge-claims can be
sustained."
Reliabilism

Reliabilism is a theory that suggests a belief is justified (or otherwise supported in such a way as to count towards knowledge) only if it is produced by processes that typically yield a sufficiently high ratio of true to false beliefs. In other words, this theory states that a true belief counts as knowledge only if it is produced by a reliable belief-forming process.

Reliabilism has been challenged by Gettier cases. Another argument that challenges reliabilism, like the Gettier cases (although it was not presented in the same short article as the Gettier cases), is the case of Henry and the barn façades. In the thought experiment, a man, Henry, is driving along and sees a number of buildings that resemble barns. Based on his perception of one of these, he concludes that he has just seen barns. While he has seen one, and the perception he based his belief on was of a real barn, all the other barn
Barn
A barn is an agricultural building used for storage and as a covered workplace. It may sometimes be used to house livestock or to store farming vehicles and equipment...

-like buildings he saw were façades. Theoretically, Henry doesn't know that he has seen a barn, despite both his belief that he has seen one being true and his belief being formed on the basis of a reliable process (i.e. his vision), since he only acquired his true belief by accident.
Other responses

The American philosopher Robert Nozick
Robert Nozick
Robert Nozick was an American political philosopher, most prominent in the 1970s and 1980s. He was a professor at Harvard University. He is best known for his book Anarchy, State, and Utopia , a right-libertarian answer to John Rawls's A Theory of Justice...

 has offered the following definition of knowledge:

S knows that P if and only if:
  • P;
  • S believes that P;
  • if P were false, S would not believe that P;
  • if P is true, S will believe that P.

Nozick believed that the third subjunctive condition served to address cases of the sort described by Gettier. Nozick further claims this condition addresses a case of the sort described by D. M. Armstrong: A father believes his son innocent of committing a particular crime, both because of faith in his son and (now) because he has seen presented in the courtroom a conclusive demonstration of his son's innocence. His belief via the method of the courtroom satisfies the four subjunctive conditions, but his faith-based belief does not. If his son were guilty, he would still believe him innocent, on the basis of faith in his son; this would violate the third subjunctive condition.

The British philosopher Simon Blackburn
Simon Blackburn
Simon Blackburn is a British academic philosopher known for his work in quasi-realism and his efforts to popularise philosophy. He recently retired as professor of philosophy at the University of Cambridge, but remains a distinguished research professor of philosophy at the University of North...

 has criticized this formulation by suggesting that we do not want to accept as knowledge beliefs, which, while they "track the truth" (as Nozick's account requires), are not held for appropriate reasons. He says that "we do not want to award the title of knowing something to someone who is only meeting the conditions through a defect, flaw, or failure, compared with someone else who is not meeting the conditions.". In addition to this, externalist accounts of knowledge, like Nozick's, are often forced to reject closure in cases where it is intuitively valid.

Timothy Williamson
Timothy Williamson
Timothy Williamson is a British philosopher whose main research interests are in philosophical logic, philosophy of language, epistemology and metaphysics....

 has advanced a theory of knowledge according to which knowledge is not justified true belief plus some extra condition(s). In his book Knowledge and its Limits
Knowledge and Its Limits
Philosopher Timothy Williamson writes in his book, Knowledge and its Limits, that the concept of knowledge cannot be analyzed into a set of other concepts; instead, it is sui generis...

, Williamson argues that the concept of knowledge cannot be analyzed into a set of other concepts—instead, it is sui generis
Sui generis
Sui generis is a Latin expression, literally meaning of its own kind/genus or unique in its characteristics. The expression is often used in analytic philosophy to indicate an idea, an entity, or a reality which cannot be included in a wider concept....

. Thus, though knowledge requires justification, truth, and belief, the word "knowledge" can't be, according to Williamson's theory, accurately regarded as simply shorthand for "justified true belief."

Alvin Goldman
Alvin Goldman
Alvin Ira Goldman is an American professor of Philosophy at Rutgers University in New Jersey. He previously taught at the University of Michigan and at the University of Arizona. He earned his PhD from Princeton University and is married to Holly Smith, a well known ethicist, former...

 writes in his Causal Theory of Knowing that in order for knowledge to truly exist there must be a causal chain
Causal chain
In philosophy, a causal chain is an ordered sequence of events in which any one event in the chain causes the next. Some philosophers believe causation relates facts, not events, in which case the meaning is adjusted accordingly.-See also:*Causality*Event...

 between the proposition and the belief of that proposition.

Externalism and internalism

Part of the debate over the nature of knowledge is a debate between epistemological externalists on the one hand, and epistemological internalists on the other.
Externalists think that factors deemed "external", meaning outside of the psychological states of those who gain knowledge, can be conditions of knowledge. For example, an externalist response to the Gettier problem is to say that, in order for a justified true belief to count as knowledge, it must be caused, in the right sort of way, by relevant facts. Such causation, to the extent that it is "outside" the mind, would count as an external, knowledge-yielding condition. Internalists, contrariwise, claim that all knowledge-yielding conditions are within the psychological states of those who gain knowledge.

While unfamiliar with the internalist/externalist debate himself, many point to René Descartes
René Descartes
René Descartes ; was a French philosopher and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the 'Father of Modern Philosophy', and much subsequent Western philosophy is a response to his writings, which are studied closely to this day...

 as an early example of the internalist approach to justification. He wrote that, because the only method by which we perceive the external world is through our senses, and that, because the senses are not infallible, we should not consider our concept of knowledge to be infallible. The only way to find anything that could be described as "indubitably true," he advocates, would be to see things "clearly and distinctly". He argued that if there is an omnipotent, good being who made the world, then it's reasonable to believe that people are made with the ability to know. However, this does not mean that man's ability to know is perfect. God gave man the ability to know, but not omniscience. Descartes said that man must use his capacities for knowledge correctly and carefully through methodological doubt. The phrase "Cogito ergo sum" (I think, therefore I am) is also commonly associated with Descartes' theory, because in his own methodological doubt, doubting everything he previously knew in order to start from a blank slate, the first thing that he could not logically bring himself to doubt was his own existence: "I do not exist" would be a contradiction in terms; the act of saying that one does not exist assumes that someone must be making the statement in the first place. Though Descartes could doubt his senses, his body and the world around him, he could not deny his own existence, because he was able to doubt and must exist in order to do so. Even if some "evil genius" were to be deceiving him, he would have to exist in order to be deceived. This one sure point provided him with what he would call his Archimedean point, in order to further develop his foundation for knowledge. Simply put, Descartes' epistemological justification depended upon his indubitable belief in his own existence and his clear and distinct knowledge of god.

Acquiring knowledge

The second question that will be dealt with is the question of how knowledge is acquired. This area of epistemology covers:
  1. Issues concerning epistemic distinctions such as that between experience and apriori  as means of creating knowledge.
  2. Distinguish between synthesis and analysis used as means of proof
  3. Debates such as the one between empiricists and rationalists.
  4. What is called "the regress problem"

A priori and a posteriori knowledge

The nature of this distinction has been disputed by various philosophers; however, the terms may be roughly defined as follows:
  • A priori knowledge is knowledge that is known independently of experience (that is, it is non-empirical, or arrived at beforehand, usually by reason). It will henceforth be acquired through anything that is independent from experience.
  • A posteriori knowledge is knowledge that is known by experience (that is, it is empirical, or arrived at afterward).

Analytic/synthetic distinction

Some propositions are such that we appear to be justified in believing them to be true just by understanding their meaning. For example, consider, "My father's brother is my uncle." We seem to be justified in believing it to be true by virtue of our knowledge of what its terms mean. Philosophers call such propositions "analytic." Synthetic propositions, on the other hand, have distinct subjects and predicates. An example of a synthetic proposition would be, "My father's brother has black hair." Kant
Immanuel Kant
Immanuel Kant was a German philosopher from Königsberg , researching, lecturing and writing on philosophy and anthropology at the end of the 18th Century Enlightenment....

 stated that all mathematical and scientifical statements are synthetic a priori propositions because they are necessarily true but our knowledge about the attributes of the mathematical or physical subjects we can only get by logical inference.

The American philosopher W. V. O. Quine, in his "Two Dogmas of Empiricism
Two Dogmas of Empiricism
W. V. Quine's paper Two Dogmas of Empiricism, published in 1951, is one of the most celebrated papers of twentieth century philosophy in the analytic tradition. According to Harvard professor of philosophy Peter Godfrey-Smith, this "paper [is] sometimes regarded as the most important in all of...

", famously challenged the distinction, arguing that the two have a blurry boundary.

Empiricism

In philosophy, empiricism is generally a theory of knowledge emphasizing the role of experience, especially experience based on perceptual observations
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...

 by the sense
Sense
Senses are physiological capacities of organisms that provide inputs for perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...

s. Certain forms treat all knowledge as empirical, while some regard disciplines such as mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 and logic
Logic
In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

 as exceptions.

There are many variants of empiricism, positivism
Positivism
Positivism is a a view of scientific methods and a philosophical approach, theory, or system based on the view that, in the social as well as natural sciences, sensory experiences and their logical and mathematical treatment are together the exclusive source of all worthwhile information....

 and realism
Realism
Realism, Realist or Realistic are terms that describe any manifestation of philosophical realism, the belief that reality exists independently of observers, whether in philosophy itself or in the applied arts and sciences. In this broad sense it is frequently contrasted with Idealism.Realism in the...

 being among the most commonly expounded but central to all empiricist epistemologies is the notion of the epistemologically privileged status of sense data
Sense data
In the philosophy of perception, the theory of sense data was a popular view held the early 20th century by philosophers such as Bertrand Russell, C. D. Broad, H. H. Price, A.J. Ayer and G.E. Moore, among others. Sense data are supposedly mind-dependent objects whose existence and properties are...

.

Idealism

Idealists believe that knowledge is primarily (at least in some areas) acquired by a priori processes or is innate
Innatism
Innatism is a philosophical doctrine that holds that the mind is born with ideas/knowledge, and that therefore the mind is not a 'blank slate' at birth, as early empiricists such as John Locke claimed...

—for example, in the form of concepts not derived from experience. The relevant theoretical processes often go by the name "intuition
Intuition (knowledge)
Intuition is the ability to acquire knowledge without inference or the use of reason. "The word 'intuition' comes from the Latin word 'intueri', which is often roughly translated as meaning 'to look inside'’ or 'to contemplate'." Intuition provides us with beliefs that we cannot necessarily justify...

". The relevant theoretical concepts may purportedly be part of the structure of the human mind
Mind
The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...

 (as in Kant
KANT
KANT is a computer algebra system for mathematicians interested in algebraic number theory, performing sophisticated computations in algebraic number fields, in global function fields, and in local fields. KASH is the associated command line interface...

's theory of transcendental idealism
Transcendental idealism
Transcendental idealism is a doctrine founded by German philosopher Immanuel Kant in the eighteenth century. Kant's doctrine maintains that human experience of things is similar to the way they appear to us — implying a fundamentally subject-based component, rather than being an activity that...

), or they may be said to exist independently of the mind (as in Plato's theory of Forms
Theory of Forms
Plato's theory of Forms or theory of Ideas asserts that non-material abstract forms , and not the material world of change known to us through sensation, possess the highest and most fundamental kind of reality. When used in this sense, the word form is often capitalized...

).

The extent to which this innate human knowledge is emphasized over experience as a means to acquire knowledge varies from idealist to idealist. Some hold that knowledge of any kind can only be gained a priori, while others claim that some knowledge can also be gained a posteriori. Consequently, the borderline between idealist epistemologies and others can be vague.

The main concept, however, central to all idealist epistemologies is the centrality of Reason: (i.e.: 'Reason' with a capital 'R'): a priori Reason: Knowledge can only be, ultimately, a product of the mind and is therefore, by definition, 'ideal'.
Ie: What is 'known' is, by definition, 'ideal'.

Rationalism

By contrast with empiricism and idealism, which emphasize the epistemologically privileged status of sense data (empirical) and the primacy of reason (theoretical) respectively, modern rationalism adds a third 'system of thinking', as Gaston Bachelard
Gaston Bachelard
Gaston Bachelard was a French philosopher. He made contributions in the fields of poetics and the philosophy of science. To the latter he introduced the concepts of epistemological obstacle and epistemological break...

 has termed these areas and holds that all three are of equal importance: The empirical, the theoretical and the abstract. Rationalism makes equal reference to all three systems of thinking.

An example of abstract thinking is Pythagoras' concept of 'pure' geometric forms: perfect triangles, squares, circles. Etc. Another example is imaginary numbers, in mathematics.

(See, esp. Scientific Rationalism (article needed) intended by its authors, Bachelard, Louis Althusser
Louis Althusser
Louis Pierre Althusser was a French Marxist philosopher. He was born in Algeria and studied at the École Normale Supérieure in Paris, where he eventually became Professor of Philosophy....

, Dominique Lecourt
Dominique Lecourt
Dominique Lecourt is a French philosopher and editor born on 5 February 1944 in Paris. He is known in the anglophone world primarily for his work developing a materialist interpretation of the philosophy of science of Gaston Bachelard....

 etc. as an attempt to walk the narrow tightrope between these two opposing dogmas of empiricism and idealism).

Constructivism

Constructivism is a view in philosophy according to which all "knowledge is a compilation of human-made constructions", “not the neutral discovery of an objective truth”. Whereas objectivism is concerned with the “object of our knowledge”, constructivism emphasises “how we construct knowledge”. Constructivism proposes new definitions for knowledge
Knowledge
Knowledge is a familiarity with someone or something unknown, which can include information, facts, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject...

 and truth
Truth
Truth has a variety of meanings, such as the state of being in accord with fact or reality. It can also mean having fidelity to an original or to a standard or ideal. In a common usage, it also means constancy or sincerity in action or character...

 that form a new paradigm
Paradigm
The word paradigm has been used in science to describe distinct concepts. It comes from Greek "παράδειγμα" , "pattern, example, sample" from the verb "παραδείκνυμι" , "exhibit, represent, expose" and that from "παρά" , "beside, beyond" + "δείκνυμι" , "to show, to point out".The original Greek...

, based on inter-subjectivity instead of the classical objectivity
Objectivity (philosophy)
Objectivity is a central philosophical concept which has been variously defined by sources. A proposition is generally considered to be objectively true when its truth conditions are met and are "mind-independent"—that is, not met by the judgment of a conscious entity or subject.- Objectivism...

, and on viability instead of truth. Piagetian constructivism, however, believes in objectivity—constructs can be validated through experimentation. The constructivist point of view is pragmatic; as Vico
Giambattista Vico
Giovanni Battista ' Vico or Vigo was an Italian political philosopher, rhetorician, historian, and jurist....

 said: "The norm of the truth is to have made it."

It originated in sociology under the term "social constructionism
Social constructionism
Social constructionism and social constructivism are sociological theories of knowledge that consider how social phenomena or objects of consciousness develop in social contexts. A social construction is a concept or practice that is the construct of a particular group...

" and has been given the name "constructivism" when referring to philosophical epistemology, though "constructionism" and "constructivism" are often used interchangeably. Constructivism has also emerged in the field of International Relations
International relations
International relations is the study of relationships between countries, including the roles of states, inter-governmental organizations , international nongovernmental organizations , non-governmental organizations and multinational corporations...

, where the writings of Alexander Wendt
Alexander Wendt
Alexander Wendt is one of the core social constructivist scholars in the field of international relations. Wendt and scholars such as Nicholas Onuf, Peter J...

 are popular. Describing the characteristic nature of International reality marked by 'anarchy' he says, "Anarchy is what states make of it."

The regress problem

"... to justify a belief one must appeal to a further justified belief. This means that one of two things can be the case. Either there are some [epistemologically basic] beliefs that we can be justified in holding without being able to justify them on the basis of any other belief, or else for each justified belief there is an infinite regress of (potential) justification [the nebula theory]. On this theory there is no rock bottom of justification. Justification just meanders in and out through our network of beliefs, stopping nowhere." The apparent impossibility of completing an infinite chain of reasoning is thought by some to support skepticism
Skepticism
Skepticism has many definitions, but generally refers to any questioning attitude towards knowledge, facts, or opinions/beliefs stated as facts, or doubt regarding claims that are taken for granted elsewhere...

. Socrates said, "The only true wisdom is in knowing you know nothing."

Response to the regress problem

Many epistemologists studying justification have attempted to argue for various types of chains of reasoning that can escape the regress problem.
Infinitism

It is not impossible for an infinite justificatory series to exist. This position is known as "infinitism
Infinitism
Infinitism is the view that knowledge may be justified by an infinite chain of reasons. It belongs to epistemology, the branch of philosophy that considers the possibility, nature, and means of knowledge.-Epistemological infinitism:...

". Infinitists typically take the infinite series to be merely potential, in the sense that an individual may have indefinitely many reasons available to him, without having consciously thought through all of these reasons when the need arises. This position is motivated in part by the desire to avoid what is seen as the arbitrariness and circularity of its chief competitors, foundationalism and coherentism. In mathematics, an infinite series will sometimes converge –
(this is the basis of calculus
Calculus
Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

) – one can therefore have an infinite series of logical arguments
and analyze it for a convergent (or non-convergent) solution.
Foundationalism

Foundationalists
Foundationalism
Foundationalism is any theory in epistemology that holds that beliefs are justified based on what are called basic beliefs . This position is intended to resolve the infinite regress problem in epistemology...

 respond to the regress problem by claiming that some beliefs that support other beliefs do not themselves require justification by other beliefs. Sometimes, these beliefs, labeled "foundational," are characterized as beliefs of whose truth one is directly aware, or as beliefs that are self-justifying, or as beliefs that are infallible. According to one particularly permissive form of foundationalism, a belief may count as foundational, in the sense that it may be presumed true until defeating evidence appears, as long as the belief seems to its believer to be true. Others have argued that a belief is justified if it is based on perception or certain a priori considerations.

The chief criticism of foundationalism is that it allegedly leads to the arbitrary or unjustified acceptance of certain beliefs.
Coherentism

Another response to the regress problem is coherentism
Coherentism
There are two distinct types of coherentism. One refers to the coherence theory of truth. The other refers to the coherence theory of justification. The coherentist theory of justification characterizes epistemic justification as a property of a belief only if that belief is a member of a coherent...

, which is the rejection of the assumption that the regress proceeds according to a pattern of linear justification. To avoid the charge of circularity, coherentists
Coherentism
There are two distinct types of coherentism. One refers to the coherence theory of truth. The other refers to the coherence theory of justification. The coherentist theory of justification characterizes epistemic justification as a property of a belief only if that belief is a member of a coherent...

 hold that an individual belief is justified circularly by the way it fits together (coheres) with the rest of the belief system of which it is a part. This theory has the advantage of avoiding the infinite regress without claiming special, possibly arbitrary status for some particular class of beliefs. Yet, since a system can be coherent while also being wrong, coherentists face the difficulty of ensuring that the whole system corresponds
Correspondence theory of truth
The correspondence theory of truth states that the truth or falsity of a statement is determined only by how it relates to the world, and whether it accurately describes that world...

 to reality. Additionally, most logicians agree that any argument that is circular is inherently invalid. That is, arguments must be linear with conclusions that flow directly from state premises.
Foundherentism

A position known as "foundherentism
Foundherentism
In epistemology, foundherentism is a theory of justification that combines elements from the two rival theories addressing infinite regress, foundationalism prone to arbitrariness, and coherentism prone to circularity...

", advanced by Susan Haack
Susan Haack
Susan Haack is an English professor of philosophy and law at the University of Miami in the United States. She has written on logic, the philosophy of language, epistemology, and metaphysics. Her pragmatism follows that of Charles Sanders Peirce.-Career:Haack is a graduate of the University of...

, is meant to be a unification of foundationalism and coherentism. One component of this theory is what is called the "analogy of the crossword puzzle." Whereas, say, infinitists regard the regress of reasons as "shaped" like a single line, Susan Haack has argued that it is more like a crossword puzzle, with multiple lines mutually supporting each other.

What do people know?

The last question that will be dealt with is the question of what people know. At the heart of this area of study is skepticism
Skepticism
Skepticism has many definitions, but generally refers to any questioning attitude towards knowledge, facts, or opinions/beliefs stated as facts, or doubt regarding claims that are taken for granted elsewhere...

, with many approaches involved trying to disprove some particular form of it.

Skepticism

Skepticism is related to the question of whether a certain knowledge is possible. "If we cannot move on to point B until we have proved point A, and if in order to prove point A we must establish it with absolute certainty, then it looks as though we will have a very hard time proving any point at all." Skeptics argue that the belief in something does not necessarily justify an assertion of knowledge of it. In this skeptics oppose foundationalism
Foundationalism
Foundationalism is any theory in epistemology that holds that beliefs are justified based on what are called basic beliefs . This position is intended to resolve the infinite regress problem in epistemology...

, which states that there have to be some basic beliefs that are justified without reference to others. The skeptical response to this can take several approaches. First, claiming that "basic beliefs" must exist, amounts to the logical fallacy of argument from ignorance
Argument from ignorance
Argument from ignorance, also known as argumentum ad ignorantiam or "appeal to ignorance" , is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false, it is "generally accepted"...

 combined with the slippery slope
Slippery slope
In debate or rhetoric, a slippery slope is a classic form of argument, arguably an informal fallacy...

. While a foundationalist would use Münchhausen Trilemma as a justification for demanding the validity of basic beliefs, a skeptic would see no problem with admitting the result.

Developments from skepticism

Early in the 20th century, the notion that belief had to be justified as such to count as knowledge lost favour. Fallibilism
Fallibilism
Fallibilism is the philosophical principle that human beings could be wrong about their beliefs, expectations, or their understanding of the world...

 is the view that knowing something does not entail certainty regarding it. Charles Sanders Peirce was a fallibilist and the most developed form of fallibilism can be traced to Karl Popper
Karl Popper
Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...

 (1902–1994) whose first book Logik Der Forschung (The Logic of Scientific Discovery
The Logic of Scientific Discovery
The Logic of Scientific Discovery is a 1934 book by Karl Popper. It was originally written in German and titled Logik der Forschung. Then Popper reformulated his book in English and republished it in 1959. This forms the rare case of a major work to appear in two languages, both written and one...

), 1934 introduced a "conjectural turn" into the philosophy of science and epistemology at large. He adumbrated a school of thought that is known as Critical Rationalism with a central tenet being the rejection of the idea that knowledge can ever be justified in the strong form that is sought by most schools of thought. His two most helpful exponents are the late William W Bartley and David Miller, recently retired from the University of Warwick. A major source of on-line material is the Critical Rationalist
Critical rationalism
Critical rationalism is an epistemological philosophy advanced by Karl Popper. Popper wrote about critical rationalism in his works, The Open Society and its Enemies Volume 2, and Conjectures and Refutations.- Criticism, not support :...

 website and also the Rathouse of Rafe Champion
Rafe Champion
Rafe Champion is an Australian writer. He was born in the Australian state of Tasmania, and grew up on a farm in the northern part of that state, near Irishtown...

.

Epistemic culture

Epistemic culture distinguishes between various settings of knowledge production and emphasizes their contextual aspects. Coined by Karin Knorr-Cetina
Karin Knorr
Karin Knorr-Cetina is an Austrian sociologist well known for her work on epistemology and Social constructionism, summarized in the books The Manufacture of Knowledge: An Essay on the Constructivist and Contextual Nature of Science and Epistemic Cultures: How the Sciences Make Knowledge...

 in her book Epistemic Cultures; she defines epistemic cultures as an "amalgam of arrangements and mechanisms - bonded through affinity, necessity and historical coincidence - which in a given field, make up how we know what we know". The term provides the conceptual framework
Conceptual framework
A conceptual framework is used in research to outline possible courses of action or to present a preferred approach to an idea or thought. For example, the philosopher Isaiah Berlin used the "hedgehogs" versus "foxes" approach; a "hedgehog" might approach the world in terms of a single organizing...

 used to demonstrate that different laboratories do not share the same "scientific" knowledge production model, but rather each is endowed with a different epistemic culture prescribing what is adequate knowledge and how it is obtained. Since its introduction, the term has been picked up and used by various researchers engaging in Science and technology studies
Science and technology studies
Science, technology and society is the study of how social, political, and cultural values affect scientific research and technological innovation, and how these, in turn, affect society, politics and culture...

.

Practical applications

Far from being purely academic, the study of epistemology is useful for a great many applications. It is particularly commonly employed in issues of law where proof of guilt or innocence may be required, or when it must be determined whether a person knew a particular fact before taking a specific action (e.g., whether an action was premeditated). Another practical application is to the design of user interfaces. For example, the skills, rules, and knowledge taxonomy of human behavior has been used by designers to develop systems that are compatible with multiple "ways of knowing": abstract analytic reasoning, experience-based 'gut feelings', and 'craft' sensorimotor skills.

Other common applications of epistemology include:
  • Education Theory
    Education theory
    Educational theory can refer to either speculative educational thought in general or to a theory of education as something that guides, explains, or describes educational practice....

  • Education Technology
  • Artificial intelligence
    Artificial intelligence
    Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...

  • Cognitive science
    Cognitive science
    Cognitive science is the interdisciplinary scientific study of mind and its processes. It examines what cognition is, what it does and how it works. It includes research on how information is processed , represented, and transformed in behaviour, nervous system or machine...

  • Cultural anthropology
    Cultural anthropology
    Cultural anthropology is a branch of anthropology focused on the study of cultural variation among humans, collecting data about the impact of global economic and political processes on local cultural realities. Anthropologists use a variety of methods, including participant observation,...

     (do different cultures have different systems of knowledge?)
  • History
    History
    History is the discovery, collection, organization, and presentation of information about past events. History can also mean the period of time after writing was invented. Scholars who write about history are called historians...

     and archaeology
    Archaeology
    Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

  • Intelligence (information) gathering
  • Knowledge management
    Knowledge management
    Knowledge management comprises a range of strategies and practices used in an organization to identify, create, represent, distribute, and enable adoption of insights and experiences...

  • Mathematics
    Mathematics
    Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

     and science
    Science
    Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

  • Medicine
    Medicine
    Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

     (diagnosis of disease)
  • Neurology
    Neurology
    Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...

  • Behavioral neuroscience
    Behavioral neuroscience
    Behavioral neuroscience, also known as biological psychology, biopsychology, or psychobiology is the application of the principles of biology , to the study of physiological, genetic, and developmental mechanisms of behavior in human and non-human animals...

  • Product testing (how can we know that the product will not fail?)
  • Psychology
    Psychology
    Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

  • Philosophy
    Philosophy
    Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

  • Linguistics
    Linguistics
    Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

  • Logic
    Logic
    In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

  • Literature
    Literature
    Literature is the art of written works, and is not bound to published sources...

  • Theology
    Theology
    Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...

     and apologetics
    Apologetics
    Apologetics is the discipline of defending a position through the systematic use of reason. Early Christian writers Apologetics (from Greek ἀπολογία, "speaking in defense") is the discipline of defending a position (often religious) through the systematic use of reason. Early Christian writers...

  • Sociology
    Sociology
    Sociology is the study of society. It is a social science—a term with which it is sometimes synonymous—which uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social activity...

  • Testimony
    Philosophical problems of testimony
    In philosophy, testimony includes any words or utterances that are presented as evidence for the claims they express. This definition may be distinguished from the legal notion of testimony in that the speaker does not have to make a declaration of the truth of the facts.The role of testimony in...



  • See also

    External links and references

    Stanford Encyclopedia of Philosophy articles:

    Other links:
    The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
     
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