Empirical evidence

Last updated

Empirical evidence is evidence obtained through sense experience or experimental procedure. It is of central importance to the sciences and plays a role in various other fields, like epistemology and law.

Contents

There is no general agreement on how the terms evidence and empirical are to be defined. Often different fields work with quite different conceptions. In epistemology, evidence is what justifies beliefs or what determines whether holding a certain belief is rational. This is only possible if the evidence is possessed by the person, which has prompted various epistemologists to conceive evidence as private mental states like experiences or other beliefs. In philosophy of science, on the other hand, evidence is understood as that which confirms or disconfirms scientific hypotheses and arbitrates between competing theories. For this role, evidence must be public and uncontroversial, like observable physical objects or events and unlike private mental states, so that evidence may foster scientific consensus. The term empirical comes from Greek ἐμπειρία empeiría, i.e. 'experience'. In this context, it is usually understood as what is observable, in contrast to unobservable or theoretical objects. It is generally accepted that unaided perception constitutes observation, but it is disputed to what extent objects accessible only to aided perception, like bacteria seen through a microscope or positrons detected in a cloud chamber, should be regarded as observable.

Empirical evidence is essential to a posteriori knowledge or empirical knowledge, knowledge whose justification or falsification depends on experience or experiment. A priori knowledge, on the other hand, is seen either as innate or as justified by rational intuition and therefore as not dependent on empirical evidence. Rationalism fully accepts that there is knowledge a priori, which is either outright rejected by empiricism or accepted only in a restricted way as knowledge of relations between our concepts but not as pertaining to the external world.

Scientific evidence is closely related to empirical evidence but not all forms of empirical evidence meet the standards dictated by scientific methods. Sources of empirical evidence are sometimes divided into observation and experimentation, the difference being that only experimentation involves manipulation or intervention: phenomena are actively created instead of being passively observed.

Background

The concept of evidence is of central importance in epistemology and in philosophy of science but plays different roles in these two fields. [1] [2] In epistemology, evidence is what justifies beliefs or what determines whether holding a certain doxastic attitude is rational. [3] [4] [5] For example, the olfactory experience of smelling smoke justifies or makes it rational to hold the belief that something is burning. It is usually held that for justification to work, the evidence has to be possessed by the believer. The most straightforward way to account for this type of evidence possession is to hold that evidence consists of the private mental states possessed by the believer. [6] [7]

Some philosophers restrict evidence even further, for example, to only conscious, propositional or factive mental states. [2] Restricting evidence to conscious mental states has the implausible consequence that many simple everyday beliefs would be unjustified. This is why it is more common to hold that all kinds of mental states, including stored but currently unconscious beliefs, can act as evidence. [6] [7] Various of the roles played by evidence in reasoning, for example, in explanatory, probabilistic and deductive reasoning, suggest that evidence has to be propositional in nature, i.e. that it is correctly expressed by propositional attitude verbs like "believe" together with a that-clause, like "that something is burning". [8] [1] [9] But it runs counter to the common practice of treating non-propositional sense-experiences, like bodily pains, as evidence. [1] [10] Its defenders sometimes combine it with the view that evidence has to be factive, i.e. that only attitudes towards true propositions constitute evidence. [8] In this view, there is no misleading evidence. The olfactory experience of smoke would count as evidence if it was produced by a fire but not if it was produced by a smoke generator. This position has problems in explaining why it is still rational for the subject to believe that there is a fire even though the olfactory experience cannot be considered evidence. [6] [2]

In philosophy of science, evidence is understood as that which confirms or disconfirms scientific hypotheses and arbitrates between competing theories. [11] [1] [2] Measurements of Mercury's "anomalous" orbit, for example, constitute evidence that plays the role of neutral arbiter between Newton's and Einstein's theory of gravitation by confirming Einstein's theory. For scientific consensus, it is central that evidence is public and uncontroversial, like observable physical objects or events and unlike private mental states. [1] [2] [5] This way it can act as a shared ground for proponents of competing theories. Two issues threatening this role are the problem of underdetermination and theory-ladenness. The problem of underdetermination concerns the fact that the available evidence often provides equal support to either theory and therefore cannot arbitrate between them. [12] [13] Theory-ladenness refers to the idea that evidence already includes theoretical assumptions. These assumptions can hinder it from acting as neutral arbiter. It can also lead to a lack of shared evidence if different scientists do not share these assumptions. [2] [14] Thomas Kuhn is an important advocate of the position that theory-ladenness concerning scientific paradigms plays a central role in science. [15] [16]

Definition

A thing is evidence for a proposition if it epistemically supports this proposition or indicates that the supported proposition is true. Evidence is empirical if it is constituted by or accessible to sensory experience. There are various competing theories about the exact definition of the terms evidence and empirical. Different fields, like epistemology, the sciences or legal systems, often associate different concepts with these terms. An important distinction among theories of evidence is whether they identify evidence with private mental states or with public physical objects. Concerning the term empirical, there is a dispute about where to draw the line between observable or empirical objects in contrast to unobservable or merely theoretical objects.

The traditional view proposes that evidence is empirical if it is constituted by or accessible to sensory experience. This involves experiences arising from the stimulation of the sense organs, like visual or auditory experiences, [2] but the term is often used in a wider sense including memories and introspection. [17] It is usually seen as excluding purely intellectual experiences, like rational insights or intuitions used to justify basic logical or mathematical principles. [18] The terms empirical and observable are closely related and sometimes used as synonyms. [19]

There is an active debate in contemporary philosophy of science as to what should be regarded as observable or empirical in contrast to unobservable or merely theoretical objects. There is general consensus that everyday objects like books or houses are observable since they are accessible via unaided perception, but disagreement starts for objects that are only accessible through aided perception. This includes using telescopes to study distant galaxies, [20] microscopes to study bacteria or using cloud chambers to study positrons. [21] So the question is whether distant galaxies, bacteria or positrons should be regarded as observable or merely theoretical objects. Some even hold that any measurement process of an entity should be considered an observation of this entity. In this sense, the interior of the Sun is observable since neutrinos originating there can be detected. [22] [23] The difficulty with this debate is that there is a continuity of cases going from looking at something with the naked eye, through a window, through a pair of glasses, through a microscope, etc. [24] [25] Because of this continuity, drawing the line between any two adjacent cases seems to be arbitrary. One way to avoid these difficulties is to hold that it is a mistake to identify the empirical with what is observable or sensible. Instead, it has been suggested that empirical evidence can include unobservable entities as long as they are detectable through suitable measurements. [26] A problem with this approach is that it is rather far from the original meaning of "empirical", which contains the reference to experience.

Knowledge a posteriori and a priori

Knowledge or the justification of a belief is said to be a posteriori if it is based on empirical evidence. A posteriori refers to what depends on experience (what comes after experience), in contrast to a priori, which stands for what is independent of experience (what comes before experience). [18] [27] For example, the proposition that "all bachelors are unmarried" is knowable a priori since its truth only depends on the meanings of the words used in the expression. The proposition "some bachelors are happy", on the other hand, is only knowable a posteriori since it depends on experience of the world as its justifier. [28] Immanuel Kant held that the difference between a posteriori and a priori is tantamount to the distinction between empirical and non-empirical knowledge. [29]

Two central questions for this distinction concern the relevant sense of "experience" and of "dependence". The paradigmatic justification of knowledge a posteriori consists in sensory experience, but other mental phenomena, like memory or introspection, are also usually included in it. [18] But purely intellectual experiences, like rational insights or intuitions used to justify basic logical or mathematical principles, are normally excluded from it. [30] [27] There are different senses in which knowledge may be said to depend on experience. In order to know a proposition, the subject has to be able to entertain this proposition, i.e. possess the relevant concepts. [18] [31] For example, experience is necessary to entertain the proposition "if something is red all over then it is not green all over" because the terms "red" and "green" have to be acquired this way. But the sense of dependence most relevant to empirical evidence concerns the status of justification of a belief. So experience may be needed to acquire the relevant concepts in the example above, but once these concepts are possessed, no further experience providing empirical evidence is needed to know that the proposition is true, which is why it is considered to be justified a priori. [18] [27]

Empiricism and rationalism

In its strictest sense, empiricism is the view that all knowledge is based on experience or that all epistemic justification arises from empirical evidence. This stands in contrast to the rationalist view, which holds that some knowledge is independent of experience, either because it is innate or because it is justified by reason or rational reflection alone. [32] [30] [33] [34] Expressed through the distinction between knowledge a priori and a posteriori from the previous section, rationalism affirms that there is knowledge a priori, which is denied by empiricism in this strict form. [35] [2] One difficulty for empiricists is to account for the justification of knowledge pertaining to fields like mathematics and logic, for example, that 3 is a prime number or that modus ponens is a valid form of deduction. The difficulty is due to the fact that there seems to be no good candidate of empirical evidence that could justify these beliefs. [30] [35] Such cases have prompted empiricists to allow for certain forms of knowledge a priori, for example, concerning tautologies or relations between our concepts. These concessions preserve the spirit of empiricism insofar as the restriction to experience still applies to knowledge about the external world. [30] In some fields, like metaphysics or ethics, the choice between empiricism and rationalism makes a difference not just for how a given claim is justified but for whether it is justified at all. This is best exemplified in metaphysics, where empiricists tend to take a skeptical position, thereby denying the existence of metaphysical knowledge, while rationalists seek justification for metaphysical claims in metaphysical intuitions. [30] [36] [37]

Scientific evidence

Scientific evidence is closely related to empirical evidence. Some theorists, like Carlos Santana, have argued that there is a sense in which not all empirical evidence constitutes scientific evidence. One reason for this is that the standards or criteria that scientists apply to evidence exclude certain evidence that is legitimate in other contexts. [38] For example, anecdotal evidence from a friend about how to treat a certain disease constitutes empirical evidence that this treatment works but would not be considered scientific evidence. [38] [39] Others have argued that the traditional empiricist definition of empirical evidence as perceptual evidence is too narrow for much of scientific practice, which uses evidence from various kinds of non-perceptual equipment. [40]

Central to scientific evidence is that it was arrived at by following scientific method in the context of some scientific theory. [41] But people rely on various forms of empirical evidence in their everyday lives that have not been obtained this way and therefore do not qualify as scientific evidence. One problem with non-scientific evidence is that it is less reliable, for example, due to cognitive biases like the anchoring effect, [42] in which information obtained earlier is given more weight, although science done poorly is also subject to such biases, as in the example of p-hacking. [38]

Observation, experimentation and scientific method

In the philosophy of science, it is sometimes held that there are two sources of empirical evidence: observation and experimentation. [43] The idea behind this distinction is that only experimentation involves manipulation or intervention: phenomena are actively created instead of being passively observed. [44] [45] [46] For example, inserting viral DNA into a bacterium is a form of experimentation while studying planetary orbits through a telescope belongs to mere observation. [47] In these cases, the mutated DNA was actively produced by the biologist while the planetary orbits are independent of the astronomer observing them. Applied to the history of science, it is sometimes held that ancient science is mainly observational while the emphasis on experimentation is only present in modern science and responsible for the scientific revolution. [44] This is sometimes phrased through the expression that modern science actively "puts questions to nature". [47] This distinction also underlies the categorization of sciences into experimental sciences, like physics, and observational sciences, like astronomy. While the distinction is relatively intuitive in paradigmatic cases, it has proven difficult to give a general definition of "intervention" applying to all cases, which is why it is sometimes outright rejected. [47] [44]

Empirical evidence is required for a hypothesis to gain acceptance in the scientific community. Normally, this validation is achieved by the scientific method of forming a hypothesis, experimental design, peer review, reproduction of results, conference presentation, and journal publication. This requires rigorous communication of hypothesis (usually expressed in mathematics), experimental constraints and controls (expressed in terms of standard experimental apparatus), and a common understanding of measurement. In the scientific context, the term semi-empirical is used for qualifying theoretical methods that use, in part, basic axioms or postulated scientific laws and experimental results. Such methods are opposed to theoretical ab initio methods, which are purely deductive and based on first principles. Typical examples of both ab initio and semi-empirical methods can be found in computational chemistry.

See also

Footnotes

  1. 1 2 3 4 5 DiFate, Victor. "Evidence". Internet Encyclopedia of Philosophy. Archived from the original on 25 June 2021. Retrieved 11 June 2021.
  2. 1 2 3 4 5 6 7 8 Kelly, Thomas (2016). "Evidence". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 8 September 2021. Retrieved 11 June 2021.
  3. Steup, Matthias; Neta, Ram (2020). "Epistemology". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 21 July 2020. Retrieved 15 June 2021.
  4. Mittag, Daniel M. "Evidentialism". Internet Encyclopedia of Philosophy. Archived from the original on 29 July 2021. Retrieved 15 June 2021.
  5. 1 2 Gage, Logan Paul (2014). "1. Introduction: Two Rival Conceptions of Evidence". Objectivity and Subjectivity in Epistemology: A Defense of the Phenomenal Conception of Evidence (PhD Thesis). Baylor University. Archived from the original on 2021-06-16. Retrieved 2021-06-21.
  6. 1 2 3 Conee, Earl; Feldman, Richard (2008). "Evidence". Epistemology: New Essays. Oxford University Press. Archived from the original on 2021-06-24. Retrieved 2021-06-21.
  7. 1 2 Piazza, Tommaso (2009). "Evidentialism and the Problem of Stored Beliefs". Philosophical Studies. 145 (2): 311–324. doi:10.1007/s11098-008-9233-1. S2CID   56299607. Archived from the original on 2021-06-16. Retrieved 2021-06-21.
  8. 1 2 Williamson, Timothy (2002). Evidence. Oxford University Press. doi:10.1093/019925656X.001.0001. ISBN   978-0-19-159867-8. Archived from the original on 2021-06-16. Retrieved 2021-06-21.
  9. "Philosophy of mind – Propositional attitudes". Encyclopedia Britannica. Archived from the original on 19 July 2020. Retrieved 2 April 2021.
  10. Huemer, Michael (2019). "Sense-Data". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2018. Retrieved 15 June 2021.
  11. Crupi, Vincenzo (2021). "Confirmation". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 17 May 2021. Retrieved 13 June 2021.
  12. Stanford, Kyle (2017). "Underdetermination of Scientific Theory". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 21 May 2021. Retrieved 15 June 2021.
  13. "Philosophy of science – Underdetermination". Encyclopedia Britannica. Archived from the original on 16 June 2021. Retrieved 15 June 2021.
  14. Andersen, Hanne; Green, Sara (2013). "Theory-Ladenness". Encyclopedia of Systems Biology. Springer. pp. 2165–2167. doi:10.1007/978-1-4419-9863-7_86. ISBN   978-1-4419-9863-7. Archived from the original on 2022-04-08. Retrieved 2021-06-21.
  15. Kuhn 1970
  16. Bird 2013
  17. "Empiricism". Encyclopedia Britannica. Archived from the original on 3 May 2021. Retrieved 17 June 2021.
  18. 1 2 3 4 5 Baehr, Jason S. "A Priori and A Posteriori". Internet Encyclopedia of Philosophy. Archived from the original on 4 October 2019. Retrieved 18 June 2021.
  19. Willer, David; Webster, Murray (1970). "Theoretical Concepts and Observables". American Sociological Review. 35 (4): 748–757. doi:10.2307/2093949. ISSN   0003-1224. JSTOR   2093949. Archived from the original on 2021-06-25. Retrieved 2021-06-21.
  20. Churchland, Paul M. (1985). "The Ontological Status of Observables: In Praise of the Superempirical Virtues". In Churchland, Paul M.; Hooker, Clifford A. (eds.). Images of Science: Essays on Realism and Empiricism. University of Chicago Press.
  21. van Fraassen, Bas (1980). The Scientific Image. Oxford University Press. pp. 16–17.
  22. Schickore, Jutta (1999). "Sehen, Sichtbarkeit Und Empirische Forschung". Journal for General Philosophy of Science. 30 (2): 273–287. doi:10.1023/A:1008374032737. S2CID   119357187. Archived from the original on 2021-06-24. Retrieved 2021-06-21.
  23. Shapere, Dudley (1982). "The Concept of Observation in Science and Philosophy". Philosophy of Science. 49 (4): 485–525. doi:10.1086/289075. S2CID   224832408. Archived from the original on 2021-06-28. Retrieved 2021-06-21.
  24. Malik, Saira (2017-03-01). "Observation Versus Experiment: An Adequate Framework for Analysing Scientific Experimentation?". Journal for General Philosophy of Science. 48 (1): 71–95. doi: 10.1007/s10838-016-9335-y . ISSN   1572-8587.
  25. Okasha, Samir (2016). "4. Realism and anti-realism". Philosophy of Science: Very Short Introduction (2nd ed.). Oxford University Press. ISBN   978-0-19-180764-0. Archived from the original on 2021-06-24. Retrieved 2021-06-21.
  26. Boyd, Nora Mills (2018). "Evidence Enriched". Philosophy of Science. 85 (3): 403–421. doi:10.1086/697747. S2CID   224833831. Archived from the original on 2021-06-24. Retrieved 2021-06-21.
  27. 1 2 3 Russell, Bruce (2020). "A Priori Justification and Knowledge". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 12 August 2021. Retrieved 20 June 2021.
  28. Gensler, Harry J. (2012). "3.7 A priori and a posteriori". Introduction to Logic. Routledge. ISBN   978-1-136-99452-4.
  29. Craig 2005 , p. 1
  30. 1 2 3 4 5 Markie, Peter (2017). "Rationalism vs. Empiricism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 9 August 2019. Retrieved 20 June 2021.
  31. Siebel, Mark (2005). "A Puzzle About Concept Possession". Grazer Philosophische Studien. 68 (1): 1–22. doi:10.1163/18756735-068001001. Archived from the original on 2021-06-28. Retrieved 2021-06-21.
  32. Feldman 2001 , p. 293
  33. Alston, William P. (1998). "Empiricism". Routledge Encyclopedia of Philosophy. Taylor and Francis. doi:10.4324/9780415249126-P014-1. ISBN   978-0415250696. Archived from the original on 2021-06-24. Retrieved 2021-06-21.
  34. Markie, Peter J. (1998). "Rationalism". Routledge Encyclopedia of Philosophy. Taylor and Francis. doi:10.4324/9780415249126-P041-1. ISBN   978-0415250696. Archived from the original on 2021-06-24. Retrieved 2021-06-21.
  35. 1 2 Teixeira, Célia (2018). "How Not to Reject the a Priori". Kriterion: Journal of Philosophy. 59 (140): 365–384. doi: 10.1590/0100-512x2018n14002ct .
  36. Friedman, Michael (2007). "The Aufbau and the rejection of metaphysics". The Cambridge Companion to Carnap. Cambridge University Press. pp. 129–152. ISBN   978-0-521-84015-6. Archived from the original on 2021-06-30. Retrieved 2021-06-21.
  37. Chakravartty, Anjan (2004). "Stance Relativism: Empiricism Versus Metaphysics". Studies in History and Philosophy of Science Part A. 35 (1): 173–184. doi:10.1016/j.shpsa.2003.12.002. Archived from the original on 2021-06-29. Retrieved 2021-06-21.
  38. 1 2 3 Santana, Carlos (2018). "Why Not All Evidence is Scientific Evidence". Episteme. 15 (2): 209–227. doi:10.1017/epi.2017.3. S2CID   152066892. Archived from the original on 2021-06-27. Retrieved 2021-06-21.
  39. Browning, Heather (2017). "Anecdotes Can Be Evidence Too". Animal Sentience. 2 (16): 13. doi: 10.51291/2377-7478.1246 . Archived from the original on 2021-06-29. Retrieved 2021-06-21.
  40. Bogen, James (2016). "Empiricism and After". In Humphreys, Paul; Chakravartty, Anjan; Morrison, Margaret; Woody, Andrea (eds.). The Oxford Handbook of Philosophy of Science. Oxford Handbooks in Philosophy. Oxford; New York: Oxford University Press. pp. 779–795. doi:10.1093/oxfordhb/9780199368815.013.12. ISBN   978-0199368815. OCLC   933596096.
  41. Bunge, Mario (1998) [1967]. Philosophy of Science: Volume 1, From Problem to Theory . Science and Technology Studies (Revised ed.). New Brunswick, NJ: Transaction Publishers. p.  21. ISBN   9780765804136. OCLC   37156799. ... empirical information is not weighed in a theoretical vacuum: every piece of evidence must be judged in the light of the theory employed in the design and implementation of the technique used to gather that information. Just as no factual theory stands by itself, so no datum constitutes an evidence for or against a theory unless it is gathered and interpreted with the help of some scientific theory.
  42. Tversky, Amos; Kahneman, Daniel (1974-09-27). "Judgment under Uncertainty: Heuristics and Biases". Science. 185 (4157): 1124–1131. Bibcode:1974Sci...185.1124T. doi:10.1126/science.185.4157.1124. ISSN   0036-8075. PMID   17835457. S2CID   143452957. Archived from the original on 2022-07-15. Retrieved 2022-06-30.
  43. Pickett 2011 , Empirical
  44. 1 2 3 Malik, Saira (2017). "Observation Versus Experiment: An Adequate Framework for Analysing Scientific Experimentation?". Journal for General Philosophy of Science. 48 (1): 71–95. doi: 10.1007/s10838-016-9335-y . Archived from the original on 2021-06-24. Retrieved 2021-06-21.
  45. González, Wenceslao J. (2010). "1. Recent approaches on Observation and Experimentation". New Methodological Perspectives on Observation and Experimentation in Science. Netbiblo. ISBN   978-84-9745-530-5.
  46. Boyd, Nora Mills; Bogen, James (2021). "Theory and Observation in Science". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 14 June 2021. Retrieved 21 June 2021.
  47. 1 2 3 Okasha, S. (2011). "Experiment, Observation and the Confirmation of Laws". Analysis. 71 (2): 222–232. doi:10.1093/analys/anr014. hdl: 1983/79e68032-e432-47de-adb5-e7ca3ff2841d . Archived from the original on 2021-06-24. Retrieved 2021-06-21.

Related Research Articles

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.

<span class="mw-page-title-main">Empiricism</span> Idea that knowledge comes only/mainly from sensory experience

In philosophy, empiricism is an epistemological view which holds that true knowledge or justification comes only or primarily from sensory experience and empirical evidence. It is one of several competing views within epistemology, along with rationalism and skepticism. Empiricists argue that empiricism is a more reliable method of finding the truth than purely using logical reasoning, because humans have cognitive biases and limitations which lead to errors of judgement. Empiricism emphasizes the central role of empirical evidence in the formation of ideas, rather than innate ideas or traditions. Empiricists may argue that traditions arise due to relations of previous sensory experiences.

Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, is a movement whose central thesis is the verification principle. This theory of knowledge asserts that only statements verifiable through direct observation or logical proof are meaningful in terms of conveying truth value, information or factual content. Starting in the late 1920s, groups of philosophers, scientists, and mathematicians formed the Berlin Circle and the Vienna Circle, which, in these two cities, would propound the ideas of logical positivism.

Philosophical methodology encompasses the methods used to philosophize and the study of these methods. Methods of philosophy are procedures for conducting research, creating new theories, and selecting between competing theories. In addition to the description of methods, philosophical methodology also compares and evaluates them.

In philosophy, rationalism is the epistemological view that "regards reason as the chief source and test of knowledge" or “the position that reason has precedence over other ways of acquiring knowledge”, often in contrast to other possible sources of knowledge such as faith, tradition, or sensory experience. More formally, rationalism is defined as a methodology or a theory "in which the criterion of truth is not sensory but intellectual and deductive".

<span class="mw-page-title-main">Knowledge</span> Awareness of facts or being competent

Knowledge is an awareness of facts, a familiarity with individuals and situations, or a practical skill. Knowledge of facts, also called propositional knowledge, is often characterized as true belief that is distinct from opinion or guesswork by virtue of justification. While there is wide agreement among philosophers that propositional knowledge is a form of true belief, many controversies focus on justification. This includes questions like how to understand justification, whether it is needed at all, and whether something else besides it is needed. These controversies intensified in the latter half of the 20th century due to a series of thought experiments called Gettier cases that provoked alternative definitions.

In philosophy of science and in epistemology, instrumentalism is a methodological view that ideas are useful instruments, and that the worth of an idea is based on how effective it is in explaining and predicting natural phenomena. According to instrumentalists, a successful scientific theory reveals nothing known either true or false about nature's unobservable objects, properties or processes. Scientific theory is merely a tool whereby humans predict observations in a particular domain of nature by formulating laws, which state or summarize regularities, while theories themselves do not reveal supposedly hidden aspects of nature that somehow explain these laws. Instrumentalism is a perspective originally introduced by Pierre Duhem in 1906.

Scientific realism is the view that the universe described by science is real regardless of how it may be interpreted. A believer of scientific realism takes the universe as described by science to be true, because of their assertion that science can be used to find the truth about both the physical and metaphysical in the Universe.

Experience refers to conscious events in general, more specifically to perceptions, or to the practical knowledge and familiarity that is produced by these processes. Understood as a conscious event in the widest sense, experience involves a subject to which various items are presented. In this sense, seeing a yellow bird on a branch presents the subject with the objects "bird" and "branch", the relation between them and the property "yellow". Unreal items may be included as well, which happens when experiencing hallucinations or dreams. When understood in a more restricted sense, only sensory consciousness counts as experience. In this sense, experience is usually identified with perception and contrasted with other types of conscious events, like thinking or imagining. In a slightly different sense, experience refers not to the conscious events themselves but to the practical knowledge and familiarity they produce. Hence, it is important that direct perceptual contact with the external world is the source of knowledge. So an experienced hiker is someone who has actually lived through many hikes, not someone who merely read many books about hiking. This is associated both with recurrent past acquaintance and the abilities learned through them.

<span class="mw-page-title-main">Hume's fork</span> English philosophy

Hume's fork, in epistemology, is a tenet elaborating upon British empiricist philosopher David Hume's emphatic, 1730s division between "relations of ideas" and "matters of fact." As phrased in Immanuel Kant's 1780s characterization of Hume's thesis, and furthered in the 1930s by the logical empiricists, Hume's fork asserts that all statements are exclusively either "analytic a priori" or "synthetic a posteriori," which, respectively, are universally true by mere definition or, however apparently probable, are unknowable without exact experience.

<span class="mw-page-title-main">Scholarly method</span> Body of principles and practices used by scholars and academics to make their claims

The scholarly method or scholarship is the body of principles and practices used by scholars and academics to make their claims about their subjects of expertise as valid and trustworthy as possible, and to make them known to the scholarly public. It comprises the methods that systemically advance the teaching, research, and practice of a scholarly or academic field of study through rigorous inquiry. Scholarship is creative, can be documented, can be replicated or elaborated, and can be and is peer reviewed through various methods. The scholarly method includes the subcategories of the scientific method, with which scientists bolster their claims, and the historical method, with which historians verify their claims.

Laurence BonJour is an American philosopher and Emeritus of Philosophy at the University of Washington.

The analytic–synthetic distinction is a semantic distinction used primarily in philosophy to distinguish between propositions that are of two types: analytic propositions and synthetic propositions. Analytic propositions are true or not true solely by virtue of their meaning, whereas synthetic propositions' truth, if any, derives from how their meaning relates to the world.

The following outline is provided as an overview of and topical guide to epistemology:

A priori and a posteriori are Latin phrases used in philosophy to distinguish types of knowledge, justification, or argument by their reliance on experience. A priori knowledge is independent from any experience. Examples include mathematics, tautologies and deduction from pure reason. A posteriori knowledge depends on empirical evidence. Examples include most fields of science and aspects of personal knowledge.

Inductivism is the traditional and still commonplace philosophy of scientific method to develop scientific theories. Inductivism aims to neutrally observe a domain, infer laws from examined cases—hence, inductive reasoning—and thus objectively discover the sole naturally true theory of the observed.

Epistemology or theory of knowledge is the branch of philosophy concerned with the nature and scope (limitations) of knowledge. It addresses the questions "What is knowledge?", "How is knowledge acquired?", "What do people know?", "How do we know what we know?", and "Why do we know what we know?". Much of the debate in this field has focused on analyzing the nature of knowledge and how it relates to similar notions such as truth, belief, and justification. It also deals with the means of production of knowledge, as well as skepticism about different knowledge claims.

<span class="mw-page-title-main">Evidence</span> Material supporting an assertion

Evidence for a proposition is what supports the proposition. It is usually understood as an indication that the proposition is true. The exact definition and role of evidence vary across different fields. In epistemology, evidence is what justifies beliefs or what makes it rational to hold a certain doxastic attitude. For example, a perceptual experience of a tree may serve as evidence to justify the belief that there is a tree. In this role, evidence is usually understood as a private mental state. In phenomenology, evidence is limited to intuitive knowledge, often associated with the controversial assumption that it provides indubitable access to truth.

<span class="mw-page-title-main">Declarative knowledge</span> Awareness of facts

Declarative knowledge is an awareness of facts that can be expressed using declarative sentences. It is also called theoretical knowledge, descriptive knowledge, propositional knowledge, and knowledge-that. It is not restricted to one specific use or purpose and can be stored in books or on computers.

A posteriori necessity is a thesis in metaphysics and the philosophy of language, that some statements of which we must acquire knowledge a posteriori are also necessarily true. It challenges previously widespread belief that only a priori knowledge can be necessary. It draws on a number of philosophical concepts such as necessity, the causal theory of reference, rigidity, and the a prioria posteriori distinction.

References