Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge . Also called theory of knowledge , it explores different types of knowledge, such as propositional knowledge about facts, practical knowledge in the form of skills, and knowledge by acquaintance as a familiarity through experience. Epistemologists study the concepts of belief , truth , and justification to understand the nature of knowledge. To discover how knowledge arises, they investigate sources of justification, such as perception , introspection , memory , reason , and testimony .
187-402: The school of skepticism questions the human ability to attain knowledge while fallibilism says that knowledge is never certain. Empiricists hold that all knowledge comes from sense experience, whereas rationalists believe that some knowledge does not depend on it. Coherentists argue that a belief is justified if it coheres with other beliefs. Foundationalists , by contrast, maintain that
374-505: A relation between a knower and a known proposition , in the case above between the person Ravi and the proposition "kangaroos hop". It is use-independent since it is not tied to one specific purpose. It is a mental representation that relies on concepts and ideas to depict reality. Because of its theoretical nature, it is often held that only relatively sophisticated creatures, such as humans, possess propositional knowledge. Propositional knowledge contrasts with non-propositional knowledge in
561-403: A self-refuting idea while others point out that it is implausible, psychologically impossible, or a pointless intellectual game. This position is based on the idea that philosophical skepticism not only rejects the existence of knowledge but seems to make knowledge claims itself at the same time. For example, to claim that there is no knowledge seems to be itself a knowledge claim. This problem
748-410: A series of thought experiments that aimed to show that some justified true beliefs do not amount to knowledge. In one of them, a person is unaware of all the fake barns in their area. By coincidence, they stop in front of the only real barn and form a justified true belief that it is a real barn. Many epistemologists agree that this is not knowledge because the justification is not directly relevant to
935-440: A "waste of time". This is often based on the idea that, because of its initial implausibility and distance from everyday life, it has little or no practical value. In this regard, Arthur Schopenhauer compares the position of radical skepticism to a border fortress that is best ignored: it is impregnable but its garrison does not pose any threat since it never sets foot outside the fortress. One defense of philosophical skepticism
1122-441: A belief is information that favors or supports it. Epistemologists understand evidence primarily in terms of mental states, for example, as sensory impressions or as other propositions that a person knows. But in a wider sense, it can also include physical objects, like bloodstains examined by forensic analysts or financial records studied by investigative journalists. Evidence is often understood in terms of probability : evidence for
1309-471: A belief is justified if the individual's evidence supports the belief and they hold the belief on the basis of this evidence. Reliabilism is an externalist theory asserting that a reliable connection between belief and truth is required for justification. Some reliabilists explain this in terms of reliable processes. According to this view, a belief is justified if it is produced by a reliable belief-formation process, like perception. A belief-formation process
1496-609: A belief makes it more likely that the belief is true. A defeater is evidence against a belief or evidence that undermines another piece of evidence. For instance, witness testimony connecting a suspect to a crime is evidence for their guilt while an alibi is a defeater. Evidentialists analyze justification in terms of evidence by saying that to be justified, a belief needs to rest on adequate evidence. The presence of evidence usually affects doubt and certainty , which are subjective attitudes toward propositions that differ regarding their level of confidence. Doubt involves questioning
1683-590: A belief, known as propositional justification , but also in whether the person holds the belief because or based on this reason, known as doxastic justification . For example, if a person has sufficient reason to believe that a neighborhood is dangerous but forms this belief based on superstition then they have propositional justification but lack doxastic justification. Sources of justification are ways or cognitive capacities through which people acquire justification. Often-discussed sources include perception , introspection , memory , reason , and testimony , but there
1870-479: A better version of it. However, some theorists distinguish philosophical skepticism from methodological skepticism in that philosophical skepticism is an approach that questions the possibility of certainty in knowledge, whereas methodological skepticism is an approach that subjects all knowledge claims to scrutiny with the goal of sorting out true from false claims. Similarly, scientific skepticism differs from philosophical skepticism in that scientific skepticism
2057-408: A claim based on other claims, but this leads to an infinite regress of justifications. One can use a dogmatic assertion, but this is not a justification. One can use circular reasoning , but this fails to justify the conclusion. A skeptical scenario is a hypothetical situation which can be used in an argument for skepticism about a particular claim or class of claims. Usually the scenario posits
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#17327805862772244-446: A cluster of loosely related ideas. Mental states are usually contrasted with physical or material aspects. This contrast is commonly based on the idea that certain features of mental phenomena are not present in the material universe as described by the natural sciences and may even be incompatible with it. Epistemic approaches emphasize that the subject has privileged access to all or at least some of their mental states. It
2431-411: A common view, this means that the person has sufficient reasons for holding this belief because they have information that supports it. Another view states that a belief is justified if it is formed by a reliable belief formation process, such as perception. The terms reasonable , warranted , and supported are closely related to the idea of justification and are sometimes used as synonyms. Justification
2618-402: A comprehensive account of all forms of rationality but it is more common to find separate treatments of specific forms of rationality that leave the relation to other forms of rationality open. There are various competing definitions of what constitutes rationality but no universally accepted answer. Some accounts focus on the relation between mental states for determining whether a given state
2805-527: A conglomeration of mental representations and propositional attitudes. Several theories in philosophy and psychology try to determine the relationship between the agent's mental state and a proposition. Instead of looking into what a mental state is, in itself, clinical psychology and psychiatry determine a person's mental health through a mental status examination . Mental states also include attitudes towards propositions , of which there are at least two— factive and non-factive, both of which entail
2992-570: A disease helps a doctor cure their patient, and knowledge of when a job interview starts helps a candidate arrive on time. The usefulness of a known fact depends on the circumstances. Knowledge of some facts may have little to no uses, like memorizing random phone numbers from an outdated phone book. Being able to assess the value of knowledge matters in choosing what information to acquire and transmit to others. It affects decisions like which subjects to teach at school and how to allocate funds to research projects. Of particular interest to epistemologists
3179-577: A feature which non-intentional states lack. A mental state is conscious if it belongs to a phenomenal experience. Unconscious mental states are also part of the mind but they lack this phenomenal dimension. Occurrent mental states are active or causally efficacious within the owner's mind while non-occurrent or standing states exist somewhere in the back of one's mind but do not currently play an active role in any mental processes . Certain mental states are rationally evaluable: they are either rational or irrational depending on whether they obey
3366-663: A formal institution. Sextus compiled and further developed the Pyrrhonists' skeptical arguments, most of which were directed against the Stoics but included arguments against all of the schools of Hellenistic philosophy , including the Academic skeptics. Sextus, as the most systematic author of the works by Hellenistic skeptics which have survived, noted that there are at least ten modes of skepticism. These modes may be broken down into three categories: one may be skeptical of
3553-577: A judgment that this event happened together with a negative evaluation of it. Brentano's distinction between judgments, phenomena of love and hate, and presentations is closely related to the more recent idea of direction of fit between mental state and world, i.e. mind-to-world direction of fit for judgments, the world-to-mind direction of fit for phenomena of love and hate and null direction of fit for mere presentations. Brentano's tripartite system of classification has been modified in various ways by Brentano's students. Alexius Meinong , for example, divides
3740-499: A kind of high-level property that can be understood in terms of fine-grained neural activity. Property dualists , on the other hand, claim that no such reductive explanation is possible. Eliminativists may reject the existence of mental properties, or at least of those corresponding to folk psychological categories such as thought and memory. Mental states play an important role in various fields, including philosophy of mind , epistemology and cognitive science . In psychology ,
3927-450: A letter, a newspaper, and a blog. Rationality is closely related to justification and the terms rational belief and justified belief are sometimes used as synonyms. However, rationality has a wider scope that encompasses both a theoretical side, covering beliefs, and a practical side, covering decisions , intentions , and actions . There are different conceptions about what it means for something to be rational. According to one view,
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#17327805862774114-415: A mental state is rational if it is based on or responsive to good reasons. Another view emphasizes the role of coherence, stating that rationality requires that the different mental states of a person are consistent and support each other. A slightly different approach holds that rationality is about achieving certain goals. Two goals of theoretical rationality are accuracy and comprehensiveness, meaning that
4301-438: A mind-to-world direction of fit : they represent the world as being a certain way and aim at truth. They contrast with desires , which are conative propositional attitudes that have a world-to-mind direction of fit and aim to change the world by representing how it should be. Desires are closely related to agency : they motivate the agent and are thus involved in the formation of intentions . Intentions are plans to which
4488-409: A person already has, asserting that a person should only change their beliefs if they have a good reason to. One motivation for adopting epistemic conservatism is that the cognitive resources of humans are limited, meaning that it is not feasible to constantly reexamine every belief. Pragmatist epistemology is a form of fallibilism that emphasizes the close relation between knowing and acting. It sees
4675-741: A person has as few false beliefs and as many true beliefs as possible. Epistemic norms are criteria to assess the cognitive quality of beliefs, like their justification and rationality. Epistemologists distinguish between deontic norms, which are prescriptions about what people should believe or which beliefs are correct, and axiological norms, which identify the goals and values of beliefs. Epistemic norms are closely related to intellectual or epistemic virtues , which are character traits like open-mindedness and conscientiousness . Epistemic virtues help individuals form true beliefs and acquire knowledge. They contrast with epistemic vices and act as foundational concepts of virtue epistemology . Evidence for
4862-418: A person knows depends on the subjective criteria or social conventions used to assess epistemic status. The debate between empiricism and rationalism centers on the origins of human knowledge. Empiricism emphasizes that sense experience is the primary source of all knowledge. Some empiricists express this view by stating that the mind is a blank slate that only develops ideas about the external world through
5049-490: A person's viewpoint as well as their characterisation of knowledge. Unmitigated skeptics believe that objective truths are unknowable and that man should live in an isolated environment in order to win mental peace. This is because everything, according to them, is changing and relative. The refusal to make judgments is of uttermost importance since there is no knowledge; only probable opinions. Philosophical skepticism has been criticized in various ways. Some criticisms see it as
5236-505: A posteriori knowledge. A priori knowledge is knowledge of non-empirical facts and does not depend on evidence from sensory experience. It belongs to fields such as mathematics and logic , like knowing that 2 + 2 = 4 {\displaystyle 2+2=4} . The contrast between a posteriori and a priori knowledge plays a central role in the debate between empiricists and rationalists on whether all knowledge depends on sensory experience. A closely related contrast
5423-402: A problem without representing it. But some theorists have argued that even these apparent counterexamples should be considered intentional when properly understood. Behaviorist definitions characterize mental states as dispositions to engage in certain publicly observable behavior as a reaction to particular external stimuli. On this view, to ascribe a belief to someone is to describe
5610-577: A specific event or object. Imagination is even further removed from the actual world in that it represents things without aiming to show how they actually are. All the aforementioned states can leave traces in memory that make it possible to relive them at a later time in the form of episodic memory. An important distinction among mental states is between sensory and non-sensory states. Sensory states involve some form of sense impressions like visual perceptions, auditory impressions or bodily pains. Non-sensory states, like thought, rational intuition or
5797-434: A state of wakefulness or sleep. But it is entirely possible that things in the world really are exactly as they appear to be to those in unnatural states (i.e., if everything were an elaborate dream). (Empiricus:59) One can have reasons for doubt that are based on the relationship between objective "facts" and subjective experience . The positions, distances, and places of objects would seem to affect how they are perceived by
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5984-598: A subject has to a proposition. The characteristic of intentional states is that they refer to or are about objects or states of affairs. Conscious states are part of the phenomenal experience while occurrent states are causally efficacious within the owner's mind, with or without consciousness. An influential classification of mental states is due to Franz Brentano, who argues that there are only three basic kinds: presentations, judgments, and phenomena of love and hate. Mental states are usually contrasted with physical or material aspects. For (non-eliminative) physicalists , they are
6171-504: A that-clause. So believing that it will rain today, for example, is a propositional attitude. It has been argued that the contrast between qualitative states and propositional attitudes is misleading since there is some form of subjective feel to certain propositional states like understanding a sentence or suddenly thinking of something. This would suggest that there are also non-sensory qualitative states and some propositional attitudes may be among them. Another problem with this contrast
6358-409: A theory but as a tool or a methodology . In this case, it may be used fruitfully to reject and improve philosophical systems despite its shortcomings as a theory. Another criticism holds that philosophical skepticism is highly counterintuitive by pointing out how far removed it is from regular life. For example, it seems very impractical, if not psychologically impossible, to suspend all beliefs at
6545-407: A threat to all kinds of philosophical theories and strives to disprove it. According to the second, philosophical skepticism is a useless distraction and should better be avoided altogether. Le Morvan himself proposes a positive third alternative: to use it as a philosophical tool in a few selected cases to overcome prejudices and foster practical wisdom. Ancient Greek skeptics were not "skeptics" in
6732-410: A true or a false proposition. According to the correspondence theory of truth , to be true means to stand in the right relation to the world by accurately describing what it is like. This means that truth is objective: a belief is true if it corresponds to a fact . The coherence theory of truth says that a belief is true if it belongs to a coherent system of beliefs. A result of this view is that truth
6919-747: A way of life. This outlook is motivated by the idea that suspending one's judgment on all kinds of issues brings with it inner peace and thereby contributes to the skeptic's happiness . Skepticism can be classified according to its scope. Local skepticism involves being skeptical about particular areas of knowledge (e.g. moral skepticism , skepticism about the external world, or skepticism about other minds), whereas radical skepticism claims that one cannot know anything—including that one cannot know about knowing anything. Skepticism can also be classified according to its method. Western philosophy has two basic approaches to skepticism. Cartesian skepticism —named somewhat misleadingly after René Descartes , who
7106-400: Is and what types of knowledge there are. It further investigates the sources of knowledge, like perception , inference , and testimony , to determine how knowledge is created. Another topic is the extent and limits of knowledge, confronting questions about what people can and cannot know. Other central concepts include belief , truth , justification , evidence , and reason . Epistemology
7293-407: Is a closely related process focused not on external physical objects but on internal mental states . For example, seeing a bus at a bus station belongs to perception while feeling tired belongs to introspection. Rationalists understand reason as a source of justification for non-empirical facts. It is often used to explain how people can know about mathematical, logical, and conceptual truths. Reason
7480-408: Is a comparative term, meaning that to know something involves distinguishing it from relevant alternatives. For example, if a person spots a bird in the garden, they may know that it is a sparrow rather than an eagle but they may not know that it is a sparrow rather than an indistinguishable sparrow hologram. Epistemic conservatism is a view about belief revision . It gives preference to the beliefs
7667-585: Is a great variety of types of mental states, which can be classified according to various distinctions. These types include perception , belief , desire , intention , emotion and memory . Many of the proposed distinctions for these types have significant overlaps and some may even be identical. Sensory states involve sense impressions, which are absent in non-sensory states . Propositional attitudes are mental states that have propositional contents, in contrast to non-propositional states . Intentional states refer to or are about objects or states of affairs,
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7854-441: Is a mental state to which the subject lacks the forms of privileged epistemic access mentioned. One way to respond to this worry is to ascribe a privileged status to conscious mental states. On such a consciousness-based approach , conscious mental states are non-derivative constituents of the mind while unconscious states somehow depend on their conscious counterparts for their existence. An influential example of this position
8041-562: Is a questioning attitude toward all kinds of knowledge claims. In this wide sense, it is quite common in everyday life: many people are ordinary skeptics about parapsychology or about astrology because they doubt the claims made by proponents of these fields. But the same people are not skeptical about other knowledge claims like the ones found in regular school books. Philosophical skepticism differs from ordinary skepticism in that it even rejects knowledge claims that belong to basic common sense and seem to be very certain. For this reason, it
8228-519: Is a special epistemic good that, unlike knowledge, is always intrinsically valuable. Wisdom is similar in this regard and is sometimes considered the highest epistemic good. It encompasses a reflective understanding with practical applications. It helps people grasp and evaluate complex situations and lead a good life. Philosophical skepticism questions the human ability to arrive at knowledge. Some skeptics limit their criticism to certain domains of knowledge. For example, religious skeptics say that it
8415-437: Is also responsible for inferential knowledge, in which one or several beliefs are used as premises to support another belief. Memory depends on information provided by other sources, which it retains and recalls, like remembering a phone number perceived earlier. Justification by testimony relies on information one person communicates to another person. This can happen by talking to each other but can also occur in other forms, like
8602-405: Is an epistemological position in which one questions the veracity of claims lacking empirical evidence . In practice, the term most commonly references the examination of claims and theories that appear to be pseudoscience , rather than the routine discussions and challenges among scientists. In ancient philosophy , skepticism was seen not just as a theory about the existence of knowledge but as
8789-456: Is an oversimplification of much more complex psychological processes. Beliefs play a central role in various epistemological debates, which cover their status as a component of propositional knowledge, the question of whether people have control over and are responsible for their beliefs , and the issue of whether there are degrees of beliefs, called credences . As propositional attitudes, beliefs are true or false depending on whether they affirm
8976-471: Is available for reasoning and guiding behavior, even if it is not associated with any subjective feel characterizing the concurrent phenomenal experience. Being an access-conscious state is similar but not identical to being an occurrent mental state, the topic of the next section. A mental state is occurrent if it is active or causally efficacious within the owner's mind. Non-occurrent states are called standing or dispositional states. They exist somewhere in
9163-470: Is avoided by functionalist approaches, which define mental states through their causal roles but allow both external and internal events in their causal network. On this view, the definition of pain-state may include aspects such as being in a state that "tends to be caused by bodily injury, to produce the belief that something is wrong with the body and ... to cause wincing or moaning". One important aspect of both behaviorist and functionalist approaches
9350-421: Is better because it is more stable. Another suggestion focuses on practical reasoning . It proposes that people put more trust in knowledge than in mere true beliefs when drawing conclusions and deciding what to do. A different response says that knowledge has intrinsic value, meaning that it is good in itself independent of its usefulness. Beliefs are mental states about what is the case, like believing that snow
9537-403: Is between analytic and synthetic truths . A sentence is analytically true if its truth depends only on the meaning of the words it uses. For instance, the sentence "all bachelors are unmarried" is analytically true because the word "bachelor" already includes the meaning "unmarried". A sentence is synthetically true if its truth depends on additional facts. For example, the sentence "snow is white"
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#17327805862779724-476: Is black. The ancient Greek Pyrrhonists developed sets of arguments to demonstrate that claims about reality cannot be adequately justified. Two sets of these arguments are well known. The oldest set is known as the ten tropes of Aenesidemus —although whether he invented the tropes or just systematized them from prior Pyrrhonist works is unknown. The tropes represent reasons for epoché ( suspension of judgment ). These are as follows: Another set are known as
9911-436: Is correct. Some philosophers, such as Timothy Williamson , reject the basic assumption underlying the analysis of knowledge by arguing that propositional knowledge is a unique state that cannot be dissected into simpler components. The value of knowledge is the worth it holds by expanding understanding and guiding action. Knowledge can have instrumental value by helping a person achieve their goals. For example, knowledge of
10098-418: Is due to John Searle , who holds that unconscious mental states have to be accessible to consciousness to count as "mental" at all. They can be understood as dispositions to bring about conscious states. This position denies that the so-called "deep unconscious", i.e. mental contents inaccessible to consciousness, exists. Another problem for consciousness-based approaches , besides the issue of accounting for
10285-471: Is engaged in her favorite computer game, she still believes that dogs have four legs and desires to get a pet dog on her next birthday. But these two states play no active role in her current state of mind. Another example comes from dreamless sleep when most or all of our mental states are standing states. Certain mental states, like beliefs and intentions , are rationally evaluable: they are either rational or irrational depending on whether they obey
10472-509: Is given in virtue of the coherence among the different mental states of a subject. This involves an holistic outlook that is less concerned with the rationality of individual mental states and more with the rationality of the person as a whole. Other accounts focus not on the relation between two or several mental states but on responding correctly to external reasons. Reasons are usually understood as facts that count in favor or against something. On this account, Scarlet's aforementioned belief
10659-414: Is important for explaining the nature of illusions. Constructivism in epistemology is the theory that how people view the world is not a simple reflection of external reality but an invention or a social construction. This view emphasizes the creative role of interpretation while undermining objectivity since social constructions may differ from society to society. According to contrastivism , knowledge
10846-458: Is impossible to have certain knowledge about the existence of deities or other religious doctrines. Similarly, moral skeptics challenge the existence of moral knowledge and metaphysical skeptics say that humans cannot know ultimate reality. Global skepticism is the widest form of skepticism, asserting that there is no knowledge in any domain. In ancient philosophy , this view was accepted by academic skeptics while Pyrrhonian skeptics recommended
11033-440: Is itself a knowledge claim. Another objection says that the abstract reasoning leading to skepticism is not convincing enough to overrule common sense. Fallibilism is another response to skepticism. Fallibilists agree with skeptics that absolute certainty is impossible. Most fallibilists disagree with skeptics about the existence of knowledge, saying that there is knowledge since it does not require absolute certainty. They emphasize
11220-466: Is no universal agreement to what extent they all provide valid justification. Perception relies on sensory organs to gain empirical information. There are various forms of perception corresponding to different physical stimuli, such as visual , auditory , haptic , olfactory , and gustatory perception. Perception is not merely the reception of sense impressions but an active process that selects, organizes, and interprets sensory signals . Introspection
11407-419: Is not just the rejection of some forms of commonly accepted knowledge but the rejection of all forms of knowledge. In this regard, we may have relatively secure beliefs in some cases but these beliefs never amount to knowledge. Weaker forms of philosophical skepticism restrict this rejection to specific fields, like the external world or moral doctrines. In some cases, knowledge per se is not rejected but it
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#173278058627711594-495: Is one of the main branches of philosophy besides fields like ethics , logic , and metaphysics . The term is also used in a slightly different sense to refer not to the branch of philosophy but to a particular position within that branch, as in Plato 's epistemology and Immanuel Kant 's epistemology. As a normative field of inquiry, epistemology explores how people should acquire beliefs. This way, it determines which beliefs fulfill
11781-479: Is only known to us through Photius , Sextus Empiricus , and to a lesser extent Diogenes Laërtius . The skeptical arguments most closely associated with Aenesidemus are the ten modes described above designed to induce epoche . The works of Sextus Empiricus (c. 200 CE) are the main surviving account of ancient Pyrrhonism. Long before Sextus' time, the Academy had abandoned skepticism and had been destroyed as
11968-504: Is particularly relevant for versions of philosophical skepticism that deny any form of knowledge. So the global skeptic denies that any claim is rationally justified but then goes on to provide arguments in an attempt to rationally justify their denial. Some philosophical skeptics have responded to this objection by restricting the denial of knowledge to certain fields without denying the existence of knowledge in general. Another defense consists in understanding philosophical skepticism not as
12155-422: Is presented but in mode or how it is presented. The most basic kind is presentation , which is involved in every mental state. Pure presentations, as in imagination, just show their object without any additional information about the veridical or evaluative aspects of their object. A judgment , on the other hand, is an attitude directed at a presentation that asserts that its presentation is either true or false, as
12342-473: Is rational because it responds correctly to the external fact that it is raining, which constitutes a reason for holding this belief. An influential classification of mental states is due to Franz Brentano . He argues that there are three basic kinds: presentations , judgments , and phenomena of love and hate . All mental states either belong to one of these kinds or are constituted by combinations of them. These different types differ not in content or what
12529-482: Is rational. In one view, a state is rational if it is well-grounded in another state that acts as its source of justification. For example, Scarlet's belief that it is raining in Manchester is rational because it is grounded in her perceptual experience of the rain while the same belief would be irrational for Frank since he lacks such a perceptual ground. A different version of such an approach holds that rationality
12716-404: Is relative since it depends on other beliefs. Further theories of truth include pragmatist , semantic , pluralist , and deflationary theories . Truth plays a central role in epistemology as a goal of cognitive processes and a component of propositional knowledge. In epistemology, justification is a property of beliefs that fulfill certain norms about what a person should believe. According to
12903-406: Is relevant to many descriptive and normative disciplines, such as the other branches of philosophy and the sciences, by exploring the principles of how they may arrive at knowledge. The word epistemology comes from the ancient Greek terms ἐπιστήμη (episteme, meaning knowledge or understanding ) and λόγος (logos, meaning study of or reason ), literally, the study of knowledge. The word
13090-411: Is reliable if most of the beliefs it causes are true. A slightly different view focuses on beliefs rather than belief-formation processes, saying that a belief is justified if it is a reliable indicator of the fact it presents. This means that the belief tracks the fact: the person believes it because it is a fact but would not believe it otherwise. Virtue epistemology is another type of externalism and
13277-447: Is somehow derivative in relation to the intentionality of mental entities. For example, a map of Addis Ababa may be said to represent Addis Ababa not intrinsically but only extrinsically because people interpret it as a representation. Another difficulty is that not all mental states seem to be intentional. So while beliefs and desires are forms of representation, this seems not to be the case for pains and itches, which may indicate
13464-402: Is something it is like for a subject to be in these states. Opponents of consciousness-based approaches often point out that despite these attempts, it is still very unclear what the term "phenomenal consciousness" is supposed to mean. This is important because not much would be gained theoretically by defining one ill-understood term in terms of another. Another objection to this type of approach
13651-461: Is sometimes claimed that this access is direct , private and infallible . Direct access refers to non-inferential knowledge. When someone is in pain, for example, they know directly that they are in pain, they do not need to infer it from other indicators like a body part being swollen or their tendency to scream when it is touched. But we arguably also have non-inferential knowledge of external objects, like trees or cats, through perception, which
13838-412: Is sometimes held that all sensory states lack intentionality. But such a view ignores that certain sensory states, like perceptions, can be intentional at the same time. It is usually accepted that all propositional attitudes are intentional. But while the paradigmatic cases of intentionality are all propositional as well, there may be some intentional attitudes that are non-propositional. This could be
14025-544: Is sometimes referred to as radical doubt . In some cases, it is even proclaimed that one does not know that "I have two hands" or that "the sun will come out tomorrow". In this regard, philosophical skepticism is not a position commonly adopted by regular people in everyday life. This denial of knowledge is usually associated with the demand that one should suspend one's beliefs about the doubted proposition . This means that one should neither believe nor disbelieve it but keep an open mind without committing oneself one way or
14212-419: Is sometimes understood as a form of reliabilism. It says that a belief is justified if it manifests intellectual virtues. Intellectual virtues are capacities or traits that perform cognitive functions and help people form true beliefs. Suggested examples include faculties like vision, memory, and introspection. In the epistemology of perception, direct and indirect realists disagree about the connection between
14399-401: Is still denied that one can ever be absolutely certain. There are only few defenders of philosophical skepticism in the strong sense. In this regard, it is much more commonly used as a theoretical tool to test theories. On this view, it is a philosophical methodology that can be utilized to probe a theory to find its weak points, either to expose it or to modify it in order to arrive at
14586-405: Is synthetically true because its truth depends on the color of snow in addition to the meanings of the words snow and white . A priori knowledge is primarily associated with analytic sentences while a posteriori knowledge is primarily associated with synthetic sentences. However, it is controversial whether this is true for all cases. Some philosophers, such as Willard Van Orman Quine , reject
14773-457: Is taken by radical skeptics , who argue that there is no knowledge at all. Epistemologists distinguish between different types of knowledge. Their primary interest is in knowledge of facts, called propositional knowledge . It is a theoretical knowledge that can be expressed in declarative sentences using a that-clause, like "Ravi knows that kangaroos hop". For this reason, it is also called knowledge-that . Epistemologists often understand it as
14960-507: Is than is not, or both is and is not, or neither is nor is not. Pyrrhonism faded as a movement following the death of Pyrrho's student Timon. The Academy became slowly more dogmatic such that in the first century BCE Aenesidemus denounced the Academics as "Stoics fighting against Stoics", breaking with the Academy to revive Pyrrhonism. Aenesidemus's best known contribution to skepticism was his now-lost book, Pyrrhonian Discourses , which
15147-537: Is that it has had important impacts on the history of philosophy at large and not just among skeptical philosophers. This is due to its critical attitude, which remains a constant challenge to the epistemic foundations of various philosophical theories. It has often provoked creative responses from other philosophers when trying to modify the affected theory to avoid the problem of skepticism. According to Pierre Le Morvan, there are two very common negative responses to philosophical skepticism. The first understands it as
15334-433: Is that minds represent the world around them, which is not the case for regular physical objects. So a person who believes that there is ice cream in the fridge represents the world as being a certain way. The ice cream can be represented but it does not itself represent the world. This is why a mind is ascribed to the person but not to the ice cream, according to the intentional approach. One advantage of it in comparison to
15521-490: Is that some states are both sensory and propositional. This is the case for perception, for example, which involves sensory impressions that represent what the world is like. This representational aspect is usually understood as involving a propositional attitude. Closely related to these distinctions is the concept of intentionality . Intentionality is usually defined as the characteristic of mental states to refer to or be about objects or states of affairs. The belief that
15708-427: Is that, according to them, the mind is multiply realizable . This means that it does not depend on the exact constitution of an entity for whether it has a mind or not. Instead, only its behavioral dispositions or its role in the causal network matter. The entity in question may be a human, an animal, a silicon-based alien or a robot. Functionalists sometimes draw an analogy to the software-hardware distinction where
15895-414: Is the dream argument . It starts from the observation that, while people are dreaming, they are usually unaware of this. This inability to distinguish between dream and regular experience is used to argue that there is no certain knowledge since a person can never be sure that they are not dreaming. Some critics assert that global skepticism is a self-refuting idea because denying the existence of knowledge
16082-413: Is the case if the beliefs are consistent and support each other. According to coherentism, justification is a holistic aspect determined by the whole system of beliefs, which resembles an interconnected web. The view of foundherentism is an intermediary position combining elements of both foundationalism and coherentism. It accepts the distinction between basic and non-basic beliefs while asserting that
16269-399: Is the case in regular perception. Phenomena of love and hate involve an evaluative attitude towards their presentation: they show how things ought to be, and the presented object is seen as either good or bad. This happens, for example, in desires. More complex types can be built up through combinations of these basic types. To be disappointed about an event, for example, can be construed as
16456-403: Is the question of whether knowledge is more valuable than a mere opinion that is true. Knowledge and true opinion often have a similar usefulness since both are accurate representations of reality. For example, if a person wants to go to Larissa , a true opinion about how to get there may help them in the same way as knowledge does. Plato already considered this problem and suggested that knowledge
16643-430: Is to be defined but also on which states count as mental. Mental states encompass a diverse group of aspects of an entity, like this entity's beliefs, desires, intentions, or pain experiences. The different approaches often result in a satisfactory characterization of only some of them. This has prompted some philosophers to doubt that there is a unifying mark of the mental and instead see the term "mental" as referring to
16830-435: Is to deny that the conscious mind has a privileged status in relation to the unconscious mind, for example, by insisting that the deep unconscious exists. Intentionality-based approaches see intentionality as the mark of the mental . The originator of this approach is Franz Brentano , who defined intentionality as the characteristic of mental states to refer to or be about objects. One central idea for this approach
17017-425: Is wet. According to foundationalism, basic beliefs are the foundation on which all other knowledge is built while non-basic beliefs constitute the superstructure resting on this foundation. Coherentists reject the distinction between basic and non-basic beliefs, saying that the justification of any belief depends on other beliefs. They assert that a belief must be in tune with other beliefs to amount to knowledge. This
17204-404: Is what distinguishes justified beliefs from superstition and lucky guesses. However, justification does not guarantee truth. For example, if a person has strong but misleading evidence, they may form a justified belief that is false. Epistemologists often identify justification as one component of knowledge. Usually, they are not only interested in whether a person has a sufficient reason to hold
17391-599: Is white or that God exists . In epistemology, they are often understood as subjective attitudes that affirm or deny a proposition , which can be expressed in a declarative sentence . For instance, to believe that snow is white is to affirm the proposition "snow is white". According to this view, beliefs are representations of what the world is like. They are kept in memory and can be retrieved when actively thinking about reality or when deciding how to act. A different view understands beliefs as behavioral patterns or dispositions to act rather than as representational items stored in
17578-684: Is why this criterion by itself is not sufficient. Another epistemic privilege often mentioned is that mental states are private in contrast to public external facts. For example, the fallen tree lying on a person's leg is directly open to perception by the bystanders while the victim's pain is private: only they know it directly while the bystanders have to infer it from their screams. It was traditionally often claimed that we have infallible knowledge of our own mental states, i.e. that we cannot be wrong about them when we have them. So when someone has an itching sensation, for example, they cannot be wrong about having this sensation. They can only be wrong about
17765-571: The Miracles . He claimed that all Cartesian knowledge, or the rational knowledge should be accessible to the entire population. Therefore, the Scriptures, aside from those by Jesus, should not be considered the secret knowledge attained from God but just the imagination of the prophets. The Scriptures, as a result of this claim, could not serve as a base for knowledge and were reduced to simple ancient historical texts. Moreover, Spinoza also rejected
17952-837: The Münchhausen trilemma and the problem of the criterion to claim that no certain belief can be achieved. This position is known as "global skepticism" or " radical skepticism ." Foundationalists have used the same trilemma as a justification for demanding the validity of basic beliefs. Epistemological nihilism rejects the possibility of human knowledge, but not necessarily knowledge in general. There are two different categories of epistemological skepticism, which can be referred to as mitigated and unmitigated skepticism. The two forms are contrasting but are still true forms of skepticism . Mitigated skepticism does not accept "strong" or "strict" knowledge claims but does, however, approve specific weaker ones. These weaker claims can be assigned
18139-588: The New Academy under Carneades (c. 213–129 BCE). Clitomachus , a student of Carneades, interpreted his teacher's philosophy as suggesting an account of knowledge based on truth-likeness. The Roman politician and philosopher, Cicero , was also an adherent of the skepticism of the New Academy, even though a return to a more dogmatic orientation of the school was already beginning to take place. In 386 CE, Augustine published Contra Academicos (Against
18326-433: The epistemic approach is that it has no problems to account for unconscious mental states: they can be intentional just like conscious mental states and thereby qualify as constituents of the mind. But a problem for this approach is that there are also some non-mental entities that have intentionality, like maps or linguistic expressions. One response to this problem is to hold that the intentionality of non-mental entities
18513-540: The knowledge base of an expert system . Knowledge contrasts with ignorance , which is often simply defined as the absence of knowledge. Knowledge is usually accompanied by ignorance since people rarely have complete knowledge of a field, forcing them to rely on incomplete or uncertain information when making decisions. Even though many forms of ignorance can be mitigated through education and research, there are certain limits to human understanding that are responsible for inevitable ignorance. Some limitations are inherent in
18700-709: The skeptical arguments cited above (the Ten Modes of Aenesidemus and the Five Modes of Agrippa ) demonstrating that beliefs cannot be justified: According to an account of Pyrrho's life by his student Timon of Phlius , Pyrrho extolled a way to become happy and tranquil: 'The things themselves are equally indifferent, and unstable, and indeterminate, and therefore neither our senses nor our opinions are either true or false. For this reason then we must not trust them, but be without opinions, and without bias, and without wavering, saying of every single thing that it no more
18887-434: The suspension of belief to achieve a state of tranquility . Overall, not many epistemologists have explicitly defended global skepticism. The influence of this position derives mainly from attempts by other philosophers to show that their theory overcomes the challenge of skepticism. For example, René Descartes used methodological doubt to find facts that cannot be doubted. One consideration in favor of global skepticism
19074-670: The suspension of judgment due to the inadequacy of evidence. This distinction is modeled after the differences between the Academic skeptics and the Pyrrhonian skeptics in ancient Greek philosophy . Pyrrhonian skepticism is a practice of suspending judgement, and skepticism in this sense is understood as a way of life that helps the practitioner achieve inner peace . Some types of philosophical skepticism reject all forms of knowledge while others limit this rejection to certain fields, for example, knowledge about moral doctrines or about
19261-430: The "5th century sophists [who] develop forms of debate which are ancestors of skeptical argumentation. They take pride in arguing in a persuasive fashion for both sides of an issue." In Hellenistic philosophy , Pyrrhonism and Academic Skepticism were the two schools of skeptical philosophy. Subsequently, the words Academic and Pyrrhonist were often used to mean skeptic . Like other Hellenistic philosophies ,
19448-775: The Academic Skeptics), which argued against claims made by the Academic Skeptics (266–90 BCE) on the following grounds: Francisco Sanches 's That Nothing is Known (published in 1581 as Quod nihil scitur ) is one of the crucial texts of Renaissance skepticism . The most notable figure of the Skepticism revival in the 1500s, Michel de Montaigne wrote about his studies of Academic Skepticism and Pyrrhonism through his Essais . His most notable writings on skepticism occurred in an essay written mostly in 1575–1576, "Apologie de Raimond Sebond", when he
19635-403: The agent is committed and which may guide actions. Intention-formation is sometimes preceded by deliberation and decision , in which the advantages and disadvantages of different courses of action are considered before committing oneself to one course. It is commonly held that pleasure plays a central role in these considerations. "Pleasure" refers to experience that feels good, that involves
19822-460: The agent's behavior while remaining unconscious, which would be an example of an unconscious occurring mental state. The distinction between occurrent and standing is especially relevant for beliefs and desires . At any moment, there seems to be a great number of things we believe or things we want that are not relevant to our current situation. These states remain inactive in the back of one's head even though one has them. For example, while Ann
20009-478: The back of one's mind but currently play no active role in any mental processes. This distinction is sometimes identified with the distinction between phenomenally conscious and unconscious mental states. It seems to be the case that the two distinctions overlap but do not fully match despite the fact that all conscious states are occurrent. This is the case because unconscious states may become causally active while remaining unconscious. A repressed desire may affect
20196-416: The belief following it and is supported by the belief preceding it. The disagreement between internalism and externalism is about the sources of justification. Internalists say that justification depends only on factors within the individual. Examples of such factors include perceptual experience, memories, and the possession of other beliefs. This view emphasizes the importance of the cognitive perspective of
20383-424: The belief in the right way. Another theory states that the belief is the product of a reliable belief formation process. Further approaches require that the person would not have the belief if it was false, that the belief is not inferred from a falsehood, that the justification cannot be undermined , or that the belief is infallible. There is no consensus on which of the proposed modifications and reconceptualizations
20570-482: The belief that the moon is closer to the earth than to the sun. When considered, this belief becomes conscious, but it is unconscious most of the time otherwise. The relation between conscious and unconscious states is a controversial topic. It is often held that conscious states are in some sense more basic with unconscious mental states depending on them. One such approach states that unconscious states have to be accessible to consciousness, that they are dispositions of
20757-474: The case when an intentional attitude is directed only at an object. In this view, Elsie's fear of snakes is a non-propositional intentional attitude while Joseph's fear that he will be bitten by snakes is a propositional intentional attitude. A mental state is conscious if it belongs to phenomenal experience . The subject is aware of the conscious mental states it is in: there is some subjective feeling to having them. Unconscious mental states are also part of
20944-439: The category of phenomena of love and hate into two distinct categories: feelings and desires. Uriah Kriegel is a contemporary defender of Brentano's approach to the classification of mental phenomena. Discussions about mental states can be found in many areas of study. In cognitive psychology and the philosophy of mind , a mental state is a kind of hypothetical state that corresponds to thinking and feeling, and consists of
21131-519: The circumstances under which they observed the cup. Evidentialism is an influential internalist view. It says that justification depends on the possession of evidence . In this context, evidence for a belief is any information in the individual's mind that supports the belief. For example, the perceptual experience of rain is evidence for the belief that it is raining. Evidentialists have suggested various other forms of evidence, including memories, intuitions, and other beliefs. According to evidentialism,
21318-525: The communal aspect of knowledge and historical epistemology examines its historical conditions. Epistemology is closely related to psychology , which describes the beliefs people hold, while epistemology studies the norms governing the evaluation of beliefs. It also intersects with fields such as decision theory , education , and anthropology . Early reflections on the nature, sources, and scope of knowledge are found in ancient Greek , Indian , and Chinese philosophy . The relation between reason and faith
21505-446: The contemporary sense of selective, localized doubt. Their concerns were epistemological, noting that truth claims could not be adequately supported, and psychotherapeutic, noting that beliefs caused mental perturbation. The Western tradition of systematic skepticism goes back at least as far as Pyrrho of Elis (b. c. 360 BCE ) and arguably to Xenophanes (b. c. 570 BCE ). Parts of skepticism also appear among
21692-402: The distinction, saying that there are no analytic truths. The analysis of knowledge is the attempt to identify the essential components or conditions of all and only propositional knowledge states. According to the so-called traditional analysis , knowledge has three components: it is a belief that is justified and true. In the second half of the 20th century, this view was put into doubt by
21879-489: The doubt can also be doubted, so on and so forth. Thus, according to Mersenne, something has to be true. Finally, Mersenne writes about all the mathematical, physical, and other scientific knowledge that is true by repeated testing, and has practical use value. Notably, Mersenne was one of the few philosophers who accepted Hobbes ' radical ideology—he saw it as a new science of man. During his long stay in Paris, Thomas Hobbes
22066-863: The end of the first Meditation Descartes writes: "I will suppose... that some evil demon of the utmost power and cunning has employed all his energies to deceive me." Skepticism, as an epistemological view, calls into question whether knowledge is possible at all. This is distinct from other known skeptical practices, including Cartesian skepticism , as it targets knowledge in general instead of individual types of knowledge. Skeptics argue that belief in something does not justify an assertion of knowledge of it. In this, skeptics oppose foundationalism , which states that there are basic positions that are self-justified or beyond justification, without reference to others. (One example of such foundationalism may be found in Spinoza 's Ethics .) Among other arguments, skeptics use
22253-468: The enjoyment of something. The topic of emotions is closely intertwined with that of agency and pleasure. Emotions are evaluative responses to external or internal stimuli that are associated with a feeling of pleasure or displeasure and motivate various behavioral reactions. Emotions are quite similar to moods , some differences being that moods tend to arise for longer durations at a time and that moods are usually not clearly triggered by or directed at
22440-597: The existence of a deceptive power that deceives our senses and undermines the justification of knowledge otherwise accepted as justified, and is proposed in order to call into question our ordinary claims to knowledge on the grounds that we cannot exclude the possibility of skeptical scenarios being true. Skeptical scenarios have received a great deal of attention in modern Western philosophy. The first major skeptical scenario in modern Western philosophy appears in René Descartes ' Meditations on First Philosophy . At
22627-430: The external world. Some theorists criticize philosophical skepticism based on the claim that it is a self-refuting idea since its proponents seem to claim to know that there is no knowledge. Other objections focus on its implausibility and distance from regular life. Philosophical skepticism is a doubtful attitude toward commonly accepted knowledge claims. It is an important form of skepticism . Skepticism in general
22814-488: The feeling of familiarity, lack sensory contents. Sensory states are sometimes equated with qualitative states and contrasted with propositional attitude states . Qualitative states involve qualia , which constitute the subjective feeling of having the state in question or what it is like to be in it. Propositional attitudes, on the other hand, are relations a subject has to a proposition. They are usually expressed by verbs like believe , desire , fear or hope together with
23001-588: The first European philosophers who were religious skeptics. He was quite familiar with the philosophy of Descartes and unprecedentedly extended the application of the Cartesian method to the religious context by analyzing religious texts with it. Spinoza sought to dispute the knowledge-claims of the Judeo-Christian-Islamic religious system by examining its two foundations: the Scripture and
23188-558: The five tropes of Agrippa : According to Victor Brochard "the five tropes can be regarded as the most radical and most precise formulation of philosophical skepticism that has ever been given. In a sense, they are still irresistible today." Pyrrho's thinking subsequently influenced the Platonic Academy , arising first in the Academic skepticism of the Middle Academy under Arcesilaus (c. 315 – 241 BCE) and then
23375-408: The form of knowledge-how and knowledge by acquaintance . Knowledge-how is a practical ability or skill, like knowing how to read or how to prepare lasagna . It is usually tied to a specific goal and not mastered in the abstract without concrete practice. To know something by acquaintance means to be familiar with it as a result of experiental contact. Examples are knowing the city of Perth , knowing
23562-446: The goal of Pyrrhonism was eudaimonia , which the Pyrrhonists sought through achieving ataraxia (an untroubled state of mind), which they found could be induced by producing a state of epoché (suspension of judgment) regarding non-evident matters. Epoché could be produced by pitting one dogma against another to undermine belief, and by questioning whether a belief could be justified. In support of this questioning Pyrrhonists developed
23749-425: The human cognitive faculties themselves, such as the inability to know facts too complex for the human mind to conceive. Others depend on external circumstances when no access to the relevant information exists. Epistemologists disagree on how much people know, for example, whether fallible beliefs about everyday affairs can amount to knowledge or whether absolute certainty is required. The most stringent position
23936-604: The impressions of sight. But one may also be lacking enough powers of sense to understand the world in its entirety: if one had an extra sense, then one might know of things in a way that the present five senses are unable to advise us of. Given that our senses can be shown to be unreliable by appealing to other senses, and so our senses may be incomplete (relative to some more perfect sense that one lacks), then it follows that all of our senses may be unreliable. (Empiricus:58) Fourth, our circumstances when one perceives anything may be either natural or unnatural, i.e., one may be either in
24123-416: The individual in the form of their mental states. It is commonly associated with the idea that the relevant factors are accessible, meaning that the individual can become aware of their reasons for holding a justified belief through introspection and reflection. Externalism rejects this view, saying that at least some relevant factors are external to the individual. This means that the cognitive perspective of
24310-404: The individual is less central while other factors, specifically the relation to truth, become more important. For instance, when considering the belief that a cup of coffee stands on the table, externalists are not only interested in the perceptual experience that led to this belief but also consider the quality of the person's eyesight, their ability to differentiate coffee from other beverages, and
24497-531: The justification of basic beliefs does not depend on other beliefs. Internalism and externalism disagree about whether justification is determined solely by mental states or also by external circumstances. Separate branches of epistemology are dedicated to knowledge found in specific fields, like scientific, mathematical, moral, and religious knowledge. Naturalized epistemology relies on empirical methods and discoveries, whereas formal epistemology uses formal tools from logic . Social epistemology investigates
24684-404: The justification of non-basic beliefs depends on coherence with other beliefs. Infinitism presents another approach to the structure of knowledge. It agrees with coherentism that there are no basic beliefs while rejecting the view that beliefs can support each other in a circular manner . Instead, it argues that beliefs form infinite justification chains, in which each link of the chain supports
24871-440: The main topic in epistemology, some theorists focus on understanding rather than knowledge. Understanding is a more holistic notion that involves a wider grasp of a subject. To understand something, a person requires awareness of how different things are connected and why they are the way they are. For example, knowledge of isolated facts memorized from a textbook does not amount to understanding. According to one view, understanding
25058-550: The mental state of acquaintance. To be acquainted with a proposition is to understand its meaning and be able to entertain it. The proposition can be true or false, and acquaintance requires no specific attitude towards that truth or falsity. Factive attitudes include those mental states that are attached to the truth of the proposition—i.e. the proposition entails truth. Some factive mental states include "perceiving that", "remembering that", "regretting that", and (more controversially) "knowing that". Non-factive attitudes do not entail
25245-428: The mind but they lack this phenomenal dimension. So it is possible for a subject to be in an unconscious mental state, like a repressed desire, without knowing about it. It is usually held that some types of mental states, like sensations or pains, can only occur as conscious mental states. But there are also other types, like beliefs and desires, that can be both conscious and unconscious. For example, many people share
25432-436: The mind emphasized by consciousness-based approaches . It may be true that pains are caused by bodily injuries and themselves produce certain beliefs and moaning behavior. But the causal profile of pain remains silent on the intrinsic unpleasantness of the painful experience itself. Some states that are not painful to the subject at all may even fit these characterizations. Theories under the umbrella of externalism emphasize
25619-415: The mind is likened to a certain type of software that can be installed on different forms of hardware. Closely linked to this analogy is the thesis of computationalism , which defines the mind as an information processing system that is physically implemented by the neural activity of the brain. One problem for all of these views is that they seem to be unable to account for the phenomenal consciousness of
25806-455: The mind possesses inborn ideas which it can access without the help of the senses. Others hold that there is an additional cognitive faculty, sometimes called rational intuition , through which people acquire nonempirical knowledge. Some rationalists limit their discussion to the origin of concepts, saying that the mind relies on inborn categories to understand the world and organize experience. Foundationalists and coherentists disagree about
25993-555: The mind's dependency on the environment. According to this view, mental states and their contents are at least partially determined by external circumstances. For example, some forms of content externalism hold that it can depend on external circumstances whether a belief refers to one object or another. The extended mind thesis states that external circumstances not only affect the mind but are part of it. The closely related view of enactivism holds that mental processes involve an interaction between organism and environment. There
26180-408: The mind. This view says that to believe that there is mineral water in the fridge is nothing more than a group of dispositions related to mineral water and the fridge. Examples are the dispositions to answer questions about the presence of mineral water affirmatively and to go to the fridge when thirsty. Some theorists deny the existence of beliefs, saying that this concept borrowed from folk psychology
26367-546: The moon has a circumference of 10921 km, for example, is a mental state that is intentional in virtue of being about the moon and its circumference. It is sometimes held that all mental states are intentional, i.e. that intentionality is the "mark of the mental". This thesis is known as intentionalism . But this view has various opponents, who distinguish between intentional and non-intentional states. Putative examples of non-intentional states include various bodily experiences like pains and itches. Because of this association, it
26554-399: The more religiously tolerant Holland where he stayed and worked for the rest of his life. Mental state A mental state , or a mental property , is a state of mind of a person. Mental states comprise a diverse class, including perception , pain / pleasure experience, belief , desire , intention , emotion , and memory . There is controversy concerning the exact definition of
26741-416: The need to keep an open and inquisitive mind since doubt can never be fully excluded, even for well-established knowledge claims like thoroughly tested scientific theories. Epistemic relativism is a related view. It does not question the existence of knowledge in general but rejects the idea that there are universal epistemic standards or absolute principles that apply equally to everyone. This means that what
26928-442: The non-mental causes, e.g. whether it is the consequence of bug bites or of a fungal infection. But various counterexamples have been presented to claims of infallibility, which is why this criterion is usually not accepted in contemporary philosophy. One problem for all epistemic approaches to the mark of the mental is that they focus mainly on conscious states but exclude unconscious states. A repressed desire , for example,
27115-473: The norms of rationality. But other states, like urges, experiences of dizziness or hunger, are arational: they are outside the domain of rationality and can be neither rational nor irrational. An important distinction within rationality concerns the difference between theoretical and practical rationality . Theoretical rationality covers beliefs and their degrees while practical rationality focuses on desires, intentions and actions. Some theorists aim to provide
27302-636: The norms of rationality. But other states are arational : they are outside the domain of rationality. A well-known classification is due to Franz Brentano, who distinguishes three basic categories of mental states: presentations , judgments , and phenomena of love and hate . There is a great variety of types of mental states including perception , bodily awareness , thought , belief , desire , motivation , intention , deliberation , decision , pleasure , emotion , mood , imagination and memory . Some of these types are precisely contrasted with each other while other types may overlap. Perception involves
27489-543: The other. Philosophical skepticism is often based on the idea that no matter how certain one is about a given belief, one could still be wrong about it. From this observation, it is argued that the belief does not amount to knowledge. Philosophical skepticism follows from the consideration that this might be the case for most or all beliefs. Because of its wide-ranging consequences, it is of central interest to theories of knowledge since it questions their very foundations. According to some definitions, philosophical skepticism
27676-453: The perceiver and the perceived object. Direct realists say that this connection is direct, meaning that there is no difference between the object present in perceptual experience and the physical object causing this experience. According to indirect realism, the connection is indirect since there are mental entities, like ideas or sense data, that mediate between the perceiver and the external world. The contrast between direct and indirect realism
27863-539: The perceiver. Perception is usually considered to be reliable but our perceptual experiences may present false information at times and can thereby mislead us. The information received in perception is often further considered in thought , in which information is mentally represented and processed. Both perceptions and thoughts often result in the formation of new or the change of existing beliefs . Beliefs may amount to knowledge if they are justified and true. They are non-sensory cognitive propositional attitudes that have
28050-469: The person: for instance, the portico may appear tapered when viewed from one end, but symmetrical when viewed at the other; and these features are different. Because they are different features, to believe the object has both properties at the same time is to believe it has two contradictory properties. Since this is absurd, one must suspend judgment about what properties it possesses due to the contradictory experiences. (Empiricus:63) One may also observe that
28237-466: The possibility for the Miracles by simply asserting that people only considered them miraculous due to their lack of understanding of the nature. By rejecting the validity of the Scriptures and the Miracles, Spinoza demolished the foundation for religious knowledge-claim and established his understanding of the Cartesian knowledge as the sole authority of knowledge-claims. Despite being deeply skeptical of
28424-814: The power of minds to refer to objects and represent the world as the mark of the mental. According to functionalist approaches , mental states are defined in terms of their role in the causal network independent of their intrinsic properties. Some philosophers deny all the aforementioned approaches by holding that the term "mental" refers to a cluster of loosely related ideas without an underlying unifying feature shared by all. Various overlapping classifications of mental states have been proposed. Important distinctions group mental phenomena together according to whether they are sensory , propositional , intentional , conscious or occurrent . Sensory states involve sense impressions like visual perceptions or bodily pains. Propositional attitudes, like beliefs and desires, are relations
28611-486: The power of reason, i.e., by treating the rational animal as a carrier of greater knowledge than the irrational animal, since the irrational animal is still adept at navigating their environment, which suggests the ability to "know" about some aspects of the environment. Secondly, the personality of the individual might also influence what they observe, since (it is argued) preferences are based on sense-impressions, differences in preferences can be attributed to differences in
28798-621: The pursuit of knowledge as an ongoing process guided by common sense and experience while always open to revision. Philosophical skepticism Philosophical skepticism ( UK spelling : scepticism ; from Greek σκέψις skepsis , "inquiry") is a family of philosophical views that question the possibility of knowledge . It differs from other forms of skepticism in that it even rejects very plausible knowledge claims that belong to basic common sense . Philosophical skeptics are often classified into two general categories: Those who deny all possibility of knowledge , and those who advocate for
28985-480: The religions, Spinoza was in fact exceedingly anti-skeptical towards reason and rationality. He steadfastly confirmed the legitimacy of reason by associating it with the acknowledgement of God, and thereby skepticism with the rational approach to knowledge was not due to problems with the rational knowledge but from the fundamental lack of understanding of God. Spinoza's religious skepticism and anti-skepticism with reason thus helped him transform epistemology by separating
29172-531: The religions. Although Hobbes himself did not go further to challenge other religious principles, his suspicion for the Mosaic authorship did significant damage to the religious traditions and paved the way for later religious skeptics like Spinoza and Isaac La Peyrère to further question some of the fundamental beliefs of the Judeo-Christian religious system. Hobbes' answer to skepticism and epistemology
29359-408: The same lines, the skeptic may insist that all things are relative, by arguing that: Finally, one has reason to disbelieve that one knows anything by looking at problems in understanding objects by themselves. Things, when taken individually, may appear to be very different from when they are in mass quantities: for instance, the shavings of a goat's horn are white when taken alone, yet the horn intact
29546-503: The same time. And even if it were possible, it would not be advisable since "the complete skeptic would wind up starving to death or walking into walls or out of windows". This criticism can allow that there are some arguments that support philosophical skepticism. However, it has been claimed that they are not nearly strong enough to support such a radical conclusion. Common-sense philosophers follow this line of thought by arguing that regular common-sense beliefs are much more reliable than
29733-640: The sense data it receives from the sensory organs. According to them, the mind can arrive at various additional insights by comparing impressions, combining them, generalizing to arrive at more abstract ideas, and deducing new conclusions from them. Empiricists say that all these mental operations depend on material from the senses and do not function on their own. Even though rationalists usually accept sense experience as one source of knowledge, they also say that important forms of knowledge come directly from reason without sense experience, like knowledge of mathematical and logical truths. According to some rationalists,
29920-506: The skeptics' intricate arguments. George Edward Moore , for example, tried to refute skepticism about the existence of the external world, not by engaging with its complex arguments, but by using a simple observation: that he has two hands . For Moore, this observation is a reliable source of knowledge incompatible with external world skepticism since it entails that at least two physical objects exist. A closely related objection sees philosophical skepticism as an "idle academic exercise" or
30107-409: The standards or epistemic goals of knowledge and which ones fail, thereby providing an evaluation of beliefs. Descriptive fields of inquiry, like psychology and cognitive sociology , are also interested in beliefs and related cognitive processes. Unlike epistemology, they study the beliefs people have and how people acquire them instead of examining the evaluative norms of these processes. Epistemology
30294-403: The structure of knowledge. Foundationalism distinguishes between basic and non-basic beliefs. A belief is basic if it is justified directly, meaning that its validity does not depend on the support of other beliefs. A belief is non-basic if it is justified by another belief. For example, the belief that it rained last night is a non-basic belief if it is inferred from the observation that the street
30481-403: The subject to enter their corresponding conscious counterparts. On this position there can be no "deep unconscious", i.e. unconscious mental states that can not become conscious. The term "consciousness" is sometimes used not in the sense of phenomenal consciousness , as above, but in the sense of access consciousness . A mental state is conscious in this sense if the information it carries
30668-489: The subjective perceiver, of the objective world , and the relation between perceiver and the world . His arguments are as follows. Subjectively , the powers of the senses and reasoning may vary among different people. And since knowledge is a product of one or the other, and since neither are reliable, knowledge would seem to be in trouble. For instance, a color-blind person sees the world quite differently from everyone else. Moreover, one cannot even give preference based on
30855-418: The taste of tsampa , and knowing Marta Vieira da Silva personally. Another influential distinction is between a posteriori and a priori knowledge. A posteriori knowledge is knowledge of empirical facts based on sensory experience, like seeing that the sun is shining and smelling that a piece of meat has gone bad. Knowledge belonging to the empirical science and knowledge of everyday affairs belongs to
31042-404: The tendency of this person to behave in certain ways. Such an ascription does not involve any claims about the internal states of this person, it only talks about behavioral tendencies. A strong motivation for such a position comes from empiricist considerations stressing the importance of observation and the lack thereof in the case of private internal mental states. This is sometimes combined with
31229-531: The term is used not just to refer to the individual mental states listed above but also to a more global assessment of a person's mental health. Various competing theories have been proposed about what the essential features of all mental states are, sometimes referred to as the search for the "mark of the mental". These theories can roughly be divided into epistemic approaches , consciousness-based approaches , intentionality-based approaches and functionalism . These approaches disagree not just on how mentality
31416-409: The term. According to epistemic approaches , the essential mark of mental states is that their subject has privileged epistemic access while others can only infer their existence from outward signs. Consciousness-based approaches hold that all mental states are either conscious themselves or stand in the right relation to conscious states. Intentionality-based approaches , on the other hand, see
31603-530: The theological knowledge-claims and the rational knowledge-claims. Pierre Bayle was a French philosopher in the late 17th century that was described by Richard Popkin to be a "supersceptic" who carried out the sceptic tradition to the extreme. Bayle was born in a Calvinist family in Carla-Bayle , and during the early stage of his life, he converted into Catholicism before returning to Calvinism. This conversion between religions caused him to leave France for
31790-405: The thesis that we could not even learn how to use mental terms without reference to the behavior associated with them. One problem for behaviorism is that the same entity often behaves differently despite being in the same situation as before. This suggests that explanation needs to make reference to the internal states of the entity that mediate the link between stimulus and response. This problem
31977-458: The things one perceives are, in a sense, polluted by experience. Any given perception—say, of a chair—will always be perceived within some context or other (i.e., next to a table, on a mat, etc.) Since this is the case, one often only speaks of ideas as they occur in the context of the other things that are paired with it, and therefore, one can never know of the true nature of the thing, but only how it appears to us in context. (Empiricus: 64) Along
32164-570: The title of "virtual knowledge", but must be to justified belief. Some mitigated skeptics are also fallibilists , arguing that knowledge does not require certainty. Mitigated skeptics hold that knowledge does not require certainty and that many beliefs are, in practice, certain to the point that they can be safely acted upon in order to live significant and meaningful lives. Unmitigated skepticism rejects both claims of virtual knowledge and strong knowledge. Characterising knowledge as strong, weak, virtual or genuine can be determined differently depending on
32351-541: The true nature of things, we can still formulate certain laws and rules for sense-perceptions through science. Additionally, he points out that we do not doubt everything because: A Pyrrhonist might refute these points by saying that senses deceive, and thus knowledge turns into infinite regress or circular logic. Thus Mersenne argues that this cannot be the case, since commonly agreed upon rules of thumb can be hypothesized and tested over time to ensure that they continue to hold. Furthermore, if everything can be doubted,
32538-442: The truth of the propositions to which they are attached. That is, one can be in one of these mental states and the proposition can be false. An example of a non-factive attitude is believing—people can believe a false proposition and people can believe a true proposition. Since there is the possibility of both, such mental states do not entail truth, and therefore, are not factive. However, belief does entail an attitude of assent toward
32725-406: The truth. More specifically, this and similar counterexamples involve some form of epistemic luck, that is, a cognitive success that results from fortuitous circumstances rather than competence. Following these thought experiments , philosophers proposed various alternative definitions of knowledge by modifying or expanding the traditional analysis. According to one view, the known fact has to cause
32912-411: The unconscious mind, is to elucidate the nature of consciousness itself. Consciousness-based approaches are usually interested in phenomenal consciousness , i.e. in qualitative experience, rather than access consciousness , which refers to information being available for reasoning and guiding behavior. Conscious mental states are normally characterized as qualitative and subjective, i.e. that there
33099-449: The use of senses, like sight, touch, hearing, smell and taste, to acquire information about material objects and events in the external world. It contrasts with bodily awareness in this sense, which is about the internal ongoings in our body and which does not present its contents as independent objects. The objects given in perception, on the other hand, are directly (i.e. non-inferentially) presented as existing out there independently of
33286-399: The validity or truth of a proposition. Certainty, by contrast, is a strong affirmative conviction, meaning that the person is free of doubt that the proposition is true. In epistemology, doubt and certainty play central roles in attempts to find a secure foundation of all knowledge and in skeptical projects aiming to establish that no belief is immune to doubt. While propositional knowledge is
33473-456: The way that people are affected by the object. (Empiricus:56) Third, the perceptions of each individual sense seemingly have nothing in common with the other senses: i.e., the color "red" has little to do with the feeling of touching a red object. This is manifest when our senses "disagree" with each other: for example, a mirage presents certain visible features, but is not responsive to any other kind of sense. In that case, our other senses defeat
33660-403: The world. While this core sense is of particular interest to epistemologists, the term also has other meanings. Understood on a social level, knowledge is a characteristic of a group of people that share ideas, understanding, or culture in general. The term can also refer to information stored in documents, such as "knowledge housed in the library" or knowledge stored in computers in the form of
33847-433: Was a central topic in the medieval period . The modern era was characterized by the contrasting perspectives of empiricism and rationalism. Epistemologists in the 20th century examined the components, structure, and value of knowledge while integrating insights from the natural sciences and linguistics . Epistemology is the philosophical study of knowledge . Also called theory of knowledge , it examines what knowledge
34034-510: Was actively involved in the circle of major skeptics like Gassendi and Mersenne who focus on the study of skepticism and epistemology . Unlike his fellow skeptic friends, Hobbes never treated skepticism as a main topic for discussion in his works. Nonetheless, Hobbes was still labeled as a religious skeptic by his contemporaries for raising doubts about Mosaic authorship of the Pentateuch and his political and psychological explanation of
34221-436: Was an author, mathematician, scientist, and philosopher. He wrote in defense of science and Christianity against atheists and Pyrrhonists before retiring to encourage development of science and the "new philosophy", which includes philosophers like Gassendi , Descartes , Galileo , and Hobbes . A major work of his in relation to Skepticism is La Verité des Sciences , in which he argues that although we may not be able to know
34408-399: Was innovatively political: he believed that moral knowledge and religious knowledge were in their nature relative, and there was no absolute standard of truth governing them. As a result, it was out of political reasons that certain truth standards about religions and ethics were devised and established in order to form a functioning government and stable society. Baruch Spinoza was among
34595-411: Was not a skeptic but used some traditional skeptical arguments in his Meditations to help establish his rationalist approach to knowledge—attempts to show that any proposed knowledge claim can be doubted. Agrippan skepticism focuses on justification rather than the possibility of doubt. According to this view, none of the ways in which one might attempt to justify a claim are adequate. One can justify
34782-451: Was only coined in the 19th century to label this field and conceive it as a distinct branch of philosophy. Knowledge is an awareness, familiarity, understanding, or skill. Its various forms all involve a cognitive success through which a person establishes epistemic contact with reality. Knowledge is typically understood as an aspect of individuals, generally as a cognitive mental state that helps them understand, interpret, and interact with
34969-533: Was reading Sextus Empiricus and trying to translate Raimond Sebond 's writing, including his proof of Christianity 's natural existence. The reception to Montaigne's translations included some criticisms of Sebond's proof. Montaigne responded to some of them in Apologie, including a defense for Sebond's logic that is skeptical in nature and similar to Pyrrhonism. His refutation is as follows: Marin Mersenne
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