What is truth?
The major theories of truth
The question of what is a proper basis for deciding how words, symbols, ideas and beliefs may properly be considered true, whether by a single person or an entire society, is dealt with by the five major substantive theories introduced below. Each theory presents perspectives that are widely shared by published scholars.](http://www.nachi.org/forum/#cite_note-EPT-4)](http://www.nachi.org/forum/#cite_note-5) There also have more recently arisen “deflationary” or “minimalist” theories of truth based on the idea that the application of a term like true to a statement does not assert anything significant about it, for instance, anything about its nature, but that the label truth is a tool of discourse used to express agreement, to emphasize claims, or to form certain types of generalizations.](http://www.nachi.org/forum/#cite_note-EPT-4)](http://www.nachi.org/forum/#cite_note-6)](http://www.nachi.org/forum/#cite_note-7)
edit] Substantive theories
Truth, holding a mirror and a serpent (1896). Olin Levi Warner, Library of Congress Thomas Jefferson Building, Washington, D.C.
edit] Correspondence theory
Main article: Correspondence theory of truth
For the truth to correspond it must first be proved by evidence or an individual’s valid opinion, which have similar meaning or context.](http://www.nachi.org/forum/#cite_note-8) This type of theory posits a relationship between thoughts or statements on the one hand, and things or objects on the other. It is a traditional model which goes back at least to some of the classical Greek philosophers such as Socrates, Plato, and Aristotle.](http://www.nachi.org/forum/#cite_note-9) This class of theories holds that the truth or the falsity of a representation is determined in principle solely by how it relates to “things”, by whether it accurately describes those “things”. An example of correspondence theory is the statement by the Thirteenth Century philosopher/theologian Thomas Aquinas: Veritas est adaequatio rei et intellectus (“Truth is the equation [or adequation] of things and intellect”), a statement which Aquinas attributed to the Ninth Century neoplatonist Isaac Israeli.](http://www.nachi.org/forum/#cite_note-10)](http://www.nachi.org/forum/#cite_note-11) Aquinas also restated the theory as: “A judgment is said to be true when it conforms to the external reality” ](http://www.nachi.org/forum/#cite_note-12)
Correspondence theory practically operates on the assumption that truth is a matter of accurately copying what was much later called “objective reality” and then representing it in thoughts, words and other symbols.](http://www.nachi.org/forum/#cite_note-13) Many modern theorists have stated that this ideal cannot be achieved independently of some analysis of additional factors.](http://www.nachi.org/forum/#cite_note-EPT-4)](http://www.nachi.org/forum/#cite_note-14) For example, language plays a role in that all languages have words that are not easily translatable into another. The German word Zeitgeist is one such example: one who speaks or understands the language may “know” what it means, but any translation of the word fails to accurately capture its full meaning (this is a problem with many abstract words, especially those derived in agglutinative languages). Thus, some words add an additional parameter to the construction of an accurate truth predicate. Among the philosophers who grappled with this problem is Alfred Tarski, whose semantic theory is summarized further below in this article.](http://www.nachi.org/forum/#cite_note-15)
Proponents of several of the theories below have gone further to assert that there are yet other issues necessary to the analysis, such as interpersonal power struggles, community interactions, personal biases and other factors involved in deciding what is seen as truth.
edit] Coherence theory
Main article: Coherence theory of truth
For coherence theories in general, truth requires a proper fit of elements within a whole system. Very often, though, coherence is taken to imply something more than simple logical consistency; often there is a demand that the propositions in a coherent system lend mutual inferential support to each other. So, for example, the completeness and comprehensiveness of the underlying set of concepts is a critical factor in judging the validity and usefulness of a coherent system.](http://www.nachi.org/forum/#cite_note-16) A pervasive tenet of coherence theories is the idea that truth is primarily a property of whole systems of propositions, and can be ascribed to individual propositions only according to their coherence with the whole. Among the assortment of perspectives commonly regarded as coherence theory, theorists differ on the question of whether coherence entails many possible true systems of thought or only a single absolute system.
Some variants of coherence theory are claimed to characterize the essential and intrinsic properties of formal systems in logic and mathematics.](http://www.nachi.org/forum/#cite_note-17) However, formal reasoners are content to contemplate axiomatically independent and sometimes mutually contradictory systems side by side, for example, the various alternative geometries. On the whole, coherence theories have been criticized as lacking justification in their application to other areas of truth, especially with respect to assertions about the natural world, empirical data in general, assertions about practical matters of psychology and society, especially when used without support from the other major theories of truth.](http://www.nachi.org/forum/#cite_note-18)
Coherence theories distinguish the thought of rationalist philosophers, particularly of Spinoza, Leibniz, and G.W.F. Hegel, along with the British philosopher F.H. Bradley.](http://www.nachi.org/forum/#cite_note-19) They have found a resurgence also among several proponents of logical positivism, notably Otto Neurath and Carl Hempel.
edit] Constructivist theory
Main article: Constructivist epistemology
Social constructivism holds that truth is constructed by social processes, is historically and culturally specific, and that it is in part shaped through the power struggles within a community. Constructivism views all of our knowledge as “constructed,” because it does not reflect any external “transcendent” realities (as a pure correspondence theory might hold). Rather, perceptions of truth are viewed as contingent on convention, human perception, and social experience. It is believed by constructivists that representations of physical and biological reality, including race, sexuality, and gender are socially constructed.
Giambattista Vico was among the first to claim that history and culture were man-made. Vico’s epistemological orientation gathers the most diverse rays and unfolds in one axiom – verum ipsum factum – “truth itself is constructed”. Hegel and Marx were among the other early proponents of the premise that truth is, or can be, socially constructed. Marx, like many critical theorists who followed, did not reject the existence of objective truth but rather distinguished between true knowledge and knowledge that has been distorted through power or ideology. For Marx scientific and true knowledge is ‘in accordance with the dialectical understanding of history’ and ideological knowledge ‘an epiphenomenal expression of the relation of material forces in a given economic arrangement’.](http://www.nachi.org/forum/#cite_note-20)
edit] Consensus theory
Main article: Consensus theory of truth
Consensus theory holds that truth is whatever is agreed upon, or in some versions, might come to be agreed upon, by some specified group. Such a group might include all human beings, or a subset thereof consisting of more than one person.
Among the current advocates of consensus theory as a useful accounting of the concept of “truth” is the philosopher Jürgen Habermas.](http://www.nachi.org/forum/#cite_note-21) Habermas maintains that truth is what would be agreed upon in an ideal speech situation.](http://www.nachi.org/forum/#cite_note-22) Among the current strong critics of consensus theory is the philosopher Nicholas Rescher.](http://www.nachi.org/forum/#cite_note-23)
edit] Pragmatic theory
Main article: Pragmatic theory of truth
The three most influential forms of the pragmatic theory of truth were introduced around the turn of the 20th century by Charles Sanders Peirce, William James, and John Dewey. Although there are wide differences in viewpoint among these and other proponents of pragmatic theory, they hold in common that truth is verified and confirmed by the results of putting one’s concepts into practice.](http://www.nachi.org/forum/#cite_note-24)
Peirce defines truth as follows: “Truth is that concordance of an abstract statement with the ideal limit towards which endless investigation would tend to bring scientific belief, which concordance the abstract statement may possess by virtue of the confession of its inaccuracy and one-sidedness, and this confession is an essential ingredient of truth.”](http://www.nachi.org/forum/#cite_note-Peirce_Truth_and_Falsity-25) This statement emphasizes Peirce’s view that ideas of approximation, incompleteness, and partiality, what he describes elsewhere as fallibilism and “reference to the future”, are essential to a proper conception of truth. Although Peirce uses words like concordance and correspondence to describe one aspect of the pragmatic sign relation, he is also quite explicit in saying that definitions of truth based on mere correspondence are no more than nominal definitions, which he accords a lower status than real definitions.
William James’s version of pragmatic theory, while complex, is often summarized by his statement that “the ‘true’ is only the expedient in our way of thinking, just as the ‘right’ is only the expedient in our way of behaving.”](http://www.nachi.org/forum/#cite_note-WJP-26) By this, James meant that truth is a quality the value of which is confirmed by its effectiveness when applying concepts to actual practice (thus, “pragmatic”).
John Dewey, less broadly than James but more broadly than Peirce, held that inquiry, whether scientific, technical, sociological, philosophical or cultural, is self-corrective over time if openly submitted for testing by a community of inquirers in order to clarify, justify, refine and/or refute proposed truths.](http://www.nachi.org/forum/#cite_note-27)
edit] Minimalist (deflationary) theories
Main article: Deflationary theory of truth
A number of philosophers reject the thesis that the concept or term truth refers to a real property of sentences or propositions. These philosophers are responding, in part, to the common use of truth predicates (e.g., that some particular thing “…is true”) which was particularly prevalent in philosophical discourse on truth in the first half of the 20th century. From this point of view, to assert the proposition “2 + 2 = 4’ is true” is logically equivalent to asserting the proposition “2 + 2 = 4”, and the phrase “is true” is completely dispensable in this and every other context. These positions are broadly described
Whichever term is used, deflationary theories can be said to hold in common that “[t]he predicate ‘true’ is an expressive convenience, not the name of a property requiring deep analysis.”](http://www.nachi.org/forum/#cite_note-EPT-4) Once we have identified the truth predicate’s formal features and utility, deflationists argue, we have said all there is to be said about truth. Among the theoretical concerns of these views is to explain away those special cases where it does appear that the concept of truth has peculiar and interesting properties. (See, e.g., Semantic paradoxes, and below.)
In addition to highlighting such formal aspects of the predicate “is true”, some deflationists point out that the concept enables us to express things that might otherwise require infinitely long sentences. For example, one cannot express confidence in Michael’s accuracy by asserting the endless sentence:
*Michael says, ‘snow is white’ and snow is white, or he says ‘roses are red’ and roses are red or he says … etc.*This assertion can also be succinctly expressed by saying: What Michael says is true.](http://www.nachi.org/forum/#cite_note-29)
edit] Performative theory of truth
Attributed to P. F. Strawson is the performative theory of truth which holds that to say “‘Snow is white’ is true” is to perform the speech act of signaling one’s agreement with the claim that snow is white (much like nodding one’s head in agreement). The idea that some statements are more actions than communicative statements is not as odd as it may seem. Consider, for example, that when the bride says “I do” at the appropriate time in a wedding, she is performing the act of taking this man to be her lawful wedded husband. She is not describing herself as taking this man, but actually doing so (perhaps the most thorough analysis of such “perlocutionary” statements is J. L. Austin, “How to Do Things With Words”](http://www.nachi.org/forum/#cite_note-30)).
Strawson holds that a similar analysis is applicable to all speech acts, not only to special perlocutionary ones: “To say a statement is true is not to make a statement about a statement, but rather to perform the act of agreeing with, accepting, or endorsing a statement. When one says ‘It’s true that it’s raining,’ one asserts no more than ‘It’s raining.’ The function of [the statement] ‘It’s true that…’ is to agree with, accept, or endorse the statement that ‘it’s raining.’”](http://www.nachi.org/forum/#cite_note-31)
edit] Redundancy and related theories
Main article: Redundancy theory of truth
According to the redundancy theory of truth, asserting that a statement is true is completely equivalent to asserting the statement itself. For example, making the assertion that " ‘Snow is white’ is true" is equivalent to asserting “Snow is white”. Redundancy theorists infer from this premise that truth is a redundant concept; that is, it is merely a word that is traditionally used in conversation or writing, generally for emphasis, but not a word that actually equates to anything in reality. This theory is commonly attributed to Frank P. Ramsey, who held that the use of words like fact and truth was nothing but a roundabout way of asserting a proposition, and that treating these words as separate problems in isolation from judgment was merely a “linguistic muddle”.](http://www.nachi.org/forum/#cite_note-EPT-4)](http://www.nachi.org/forum/#cite_note-32)](http://www.nachi.org/forum/#cite_note-33)
A variant of redundancy theory is the disquotational theory which uses a modified form of Tarski’s schema: To say that ‘“P” is true’ is to say that P. Yet another version of deflationism is the prosentential theory of truth, first developed by Dorothy Grover, Joseph Camp, and Nuel Belnap as an elaboration of Ramsey’s claims. They argue that sentences like “That’s true”, when said in response to “It’s raining”, are prosentences, expressions that merely repeat the content of other expressions. In the same way that it means the same as my dog in the sentence My dog was hungry, so I fed it, That’s true is supposed to mean the same as It’s raining — if you say the latter and I then say the former. These variations do not necessarily follow Ramsey in asserting that truth is not a property, but rather can be understood to say that, for instance, the assertion “P” may well involve a substantial truth, and the theorists in this case are minimalizing only the redundancy or prosentence involved in the statement such as “that’s true.”](http://www.nachi.org/forum/#cite_note-EPT-4)
Deflationary principles do not apply to representations that are not analogous to sentences, and also do not apply to many other things that are commonly judged to be true or otherwise. Consider the analogy between the sentence “Snow is white” and the character named Snow White, both of which can be true in some sense. To a minimalist, saying “Snow is white is true” is the same as saying “Snow is white,” but to say “Snow White is true” is not the same as saying “Snow White.”
edit] Pluralist theories
Main article: Pluralist theories of truth
Several of the major theories of truth hold that there is a particular property the having of which makes a belief or proposition true. Pluralist theories of truth assert that there may be more than one property that makes propositions true: ethical propositions might be true by virtue of coherence. Propositions about the physical world might be true by corresponding to the objects and properties they are about.
Some of the pragmatic theories, such as those by Charles Peirce and William James, included aspects of correspondence, coherence and constructivist theories.](http://www.nachi.org/forum/#cite_note-Peirce_Truth_and_Falsity-25)](http://www.nachi.org/forum/#cite_note-WJP-26) Crispin Wright argued in his 1992 book Truth and Objectivity that any predicate which satisfied certain platitudes about truth qualified as a truth predicate. In some discourses, Wright argued, the role of the truth predicate might be played by the notion of superassertibility.](http://www.nachi.org/forum/#cite_note-34) Michael Lynch, in a 2009 book Truth as One and Many, argued that we should see truth as a functional property capable of being multiply manifested in distinct properties like correspondence or coherence.](http://www.nachi.org/forum/#cite_note-35)
edit] Most believed theories
According to a survey of professional philosophers and others on their philosophical views which was carried out in November 2009 (taken by 3226 respondents, including 1803 philosophy faculty members and/or PhDs and 829 philosophy graduate students) 44.9% of respondents accept or lean towards correspondence theories, 20.7% accept or lean towards deflationary theories and 13.8% epistemic theories.](http://www.nachi.org/forum/#cite_note-36)