The terms "a priori" and "a posteriori" are used in philosophy to distinguish between deductive and inductive reasoning, respectively. Philosophy is the study of general problems concerning matters such as existence knowledge truth beauty justice validity mind and language Deductive reasoning is Reasoning which uses deductive Arguments to move from given statements ( Premises to Conclusions which must be true if the Induction or inductive reasoning, sometimes called inductive logic, is the process of Reasoning in which the premises of an argument are believed Attempts to define clearly or explain a priori and a posteriori knowledge are part of a central thread in epistemology, the study of knowledge. Epistemology (from Greek επιστήμη - episteme, "knowledge" + λόγος, " Logos " or theory of knowledge Knowledge is defined ( Oxford English Dictionary) variously as (i expertise and skills acquired by a person through experience or education the theoretical or practical understanding The exact definitions of the terms have changed over time and vary between fields.
In philosophy, a priori knowledge is independent of experience, while a posteriori knowledge is dependent on experience. Experience as a general concept comprises Knowledge of or skill in or Observation of some thing or some event gained through involvement in or In other words, statements that are, a priori, true are tautologies. In Propositional logic, a tautology (from the Greek word ταυτολογία is a Propositional formula that is true under any possible valuation
Economists sometimes use "a priori" to describe a step in an argument the truth of which can be taken as self-evident. "A posteriori", on the other hand, implies that an argument must be based upon empirical evidence.
The terms "a priori" and "a posteriori" are used in philosophy to distinguish two supposedly different types knowledge: a priori knowledge is gained independently of experience, and a posteriori knowledge is knowledge based on experience Thus, they are primarily used as adjectives to modify the noun "knowledge", or taken to be compound nouns that refer to types of knowledge (for example, "a priori knowledge"). In Grammar, an adjective is a word whose main syntactic role is to modify a Noun or Pronoun, giving more information about the However, "a priori" is sometimes used as an adjective to modify other nouns, such as "truth. " Additionally, philosophers often modify this use. For example, "apriority" and "aprioricity" are sometimes used as nouns to refer (approximately) to the quality of being a priori. Examples of proposed candidates of a priori knowledge include "2+5=7", the propositions of Euclidean geometry, and "all bachelors are unmarried"; Examples of proposed candidates of a posteriori reasoning include "Protons are made of quarks" and "Hitler died in 1945. Euclidean geometry is a mathematical system attributed to the Greek Mathematician Euclid of Alexandria. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive In Physics, a quark (kwɔrk kwɑːk or kwɑːrk is a type of Subatomic particle. Hi and welcome to Wikipedia! Please understand that this article is frequently vandalized and vandalism is reverted immediately "
Although definitions and use of the terms have varied in the history of philosophy, they have consistently labelled two separate epistemological notions. The intuitive distinction between a priori and a posteriori knowledge is best seen in examples. To borrow from Jerry Fodor (2004), take, for example, the proposition expressed by the sentence, "George V reigned from 1910 to 1936. Jerry Alan Fodor (born 1935 in New York City, New York) is an American philosopher and cognitive scientist. In Logic and Philosophy, proposition refers to either (a the content or Meaning of a meaningful Declarative sentence " This is something (if true) that one must come to know a posteriori, because it expresses an empirical fact unknowable by reason alone. By contrast, consider the proposition, "If George V reigned at all, then he reigned for a while. " This is something that one knows a priori, because it expresses a statement that one can derive by reason alone.
In statistical theory, a priori means knowledge present before a particular observation is made, and a posteriori denotes knowledge once the outcome of the observation is taken into account. Statistics is a mathematical science pertaining to the collection analysis interpretation or explanation and presentation of Data. This distinction is central to Bayesian inference, which takes a more general view of knowledge than the traditional philosophical dichotomy. Bayesian inference is Statistical inference in which evidence or observations are used to update or to newly infer the Probability that a hypothesis may be true A dichotomy is any splitting of a whole into exactly two non-overlapping parts
The phrases "a priori" and "a posteriori" are Latin for "from what comes before" and "from what comes later" (or, less literally, "before experience" and "after experience"). Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. An early philosophical use of what might be considered a notion of a priori knowledge (though not by called by that name) is Plato's theory of recollection, related in the dialogue Meno (380 B. Biography Early life Birth and family Plato was born in Athens Greece Innatism is a philosophical doctrine that holds that the mind is born with ideas/knowledge and that therefore the mind is not a ' Blank slate ' at birth as early empiricists Meno is a Socratic dialogue written by Plato. Written in the Socratic dialectic style, it attempts to determine the definition of Virtue C. E. ), according to which something like a priori knowledge is knowledge inherent in the human mind.
The German philosopher Immanuel Kant (1781) advocated a blend of rationalist and empiricist theories. Immanuel Kant (ɪmanuəl kant 22 April 1724 12 February 1804 was an 18th-century German Philosopher from the Prussian city of Königsberg Kant states, "That all our knowledge begins with experience, there can be no doubt. . . But. . . it by no means follows that all arises out of experience. " According to Kant, a priori knowledge is transcendental, or based on the form of all possible experience, while a posteriori knowledge is empirical, based on the content of experience. Kant states, ". . . it is quite possible that our empirical knowledge is a compound of that which we receive through impressions, and that which the faculty of cognition supplies from itself (sensuous impressions giving merely the occasion). " Thus, unlike the empiricists, Kant thinks that a priori knowledge is independent of the content of experience; however, unlike the rationalists, Kant thinks that a priori knowledge, in its pure form, that is without the admixture of any empirical content, is knowledge limited to the deduction of the conditions of possible experience. These a priori, or transcendental conditions, are seated in one's cognitive faculties, and are not provided by experience in general or any experience in particular. Kant nominated and explored the possibility of a transcendental logic with which to consider the deduction of the a priori in its pure form. Concepts such as time and cause are counted among the list of pure a priori forms. For other uses see Time (disambiguation Time is a component of a measuring system used to sequence events to compare the durations of Causality (but not causation) denotes a necessary relationship between one event (called cause and another event (called effect) which is the direct consequence Kant reasoned that the pure a priori forms are established via his transcendental aesthetic and transcendental logic. The Critique of Pure Reason (Kritik der reinen Vernunft by Immanuel Kant, first published in 1781, second edition 1787, is one He claimed that the human subject would not have the kind of experience that she has were these a priori forms not in some way constitutive of her as a human subject. For instance, she would not experience the world as an orderly, rule-governed place unless time and cause were operative in her cognitive faculties. The claim is more formally known as Kant's transcendental deduction and it is the central argument of his major work, the Critique of Pure Reason. The Critique of Pure Reason (Kritik der reinen Vernunft by Immanuel Kant, first published in 1781, second edition 1787, is one The transcendental deduction does not avoid the fact or objectivity of time and cause, but does, in its consideration of a possible logic of the a priori, attempt to make the case for the fact of subjectivity, what consititutes subjectivity and what relation it holds with objectivity and the empirical. Objectivity is both an important and very difficult concept to pin down in philosophy Subjectivity refers to a subject's perspective particularly feelings beliefs and desires
Several philosophers reacting to Kant sought to explain a priori knowledge without appealing to, as Paul Boghossian explains, "a special faculty. . . that has never been described in satisfactory terms. " One theory, popular among the logical positivists of the early twentieth century, is what Boghossian calls the "analytic explanation of the a priori. Logical positivism (later and more accurately called logical empiricism) is a school of philosophy that combines Empiricism, the idea that observational evidence is " The distinction between analytic and synthetic propositions was first introduced by Kant. The analytic-synthetic distinction is a conceptual distinction used primarily in Philosophy to distinguish propositions into two types analytic propositions and While Kant's original distinction was primarily drawn in terms of conceptual containment, the contemporary version of the distinction primarily involves, as Quine put it, the notions of "true by virtue of meanings and independently of fact. Willard Van Orman Quine (June 25 1908 Akron, Ohio &ndash December 25 2000 (known to intimates as "Van" " Analytic propositions are thought to be true in virtue of their meaning alone, while a priori synthetic propositions are thought to be true in virtue of their meaning and certain facts about the world. According to the analytic explanation of the a priori, all a priori knowledge is analytic; so a priori knowledge need not require a special faculty of pure intuition, since it can be accounted for simply by one's ability to understand the meaning of the proposition in question. In short, proponents of this explanation claimed to have reduced a dubious metaphysical faculty of pure reason to a legitimate linguistic notion of analyticity.
However, the analytic explanation of a priori knowledge has undergone several criticisms. Most notably, the American philosopher W. V. O. Quine (1951) argued that the analytic-synthetic distinction is illegitimate (see Quine's rejection of the analytic-synthetic distinction). Willard Van Orman Quine (June 25 1908 Akron, Ohio &ndash December 25 2000 (known to intimates as "Van" Willard Van Orman Quine (June 25 1908 Akron, Ohio &ndash December 25 2000 (known to intimates as "Van" Quine states: "But for all its a priori reasonableness, a boundary between analytic and synthetic statements simply has not been drawn. That there is such a distinction to be drawn at all is an unempirical dogma of empiricists, a metaphysical article of faith. " While the soundness of Quine's critique is highly disputed, it had a powerful effect on the project of explaining the a priori in terms of the analytic.
The metaphysical distinction between necessary and contingent truths has also been related to a priori and a posteriori knowledge. A proposition that is necessarily true is one whose negation is self-contradictory (thus, it is said to be true in every possible world). A modal logic is any system of formal logic that attempts to deal with modalities. Consider the proposition that all bachelors are unmarried. Theoretically, its negation, the proposition that some bachelors are married, is incoherent, because the concept of being unmarried (or the meaning of the word "unmarried") is part of the concept of being a bachelor (or part of the definition of the word "bachelor"). To the extent that contradictions are impossible, self-contradictory propositions are necessarily false, because it is impossible for them to be true. Thus, the negation of a self-contradictory proposition is supposed to be necessarily true. By contrast, a proposition that is contingently true is one whose negation is not self-contradictory (thus, it is said that it is not true in every possible world). As Jason Baehr states, it seems plausible that all necessary propositions are known a priori, because "[s]ense experience can tell us only about the actual world and hence about what is the case; it can say nothing about what must or must not be the case. "
Following Kant, some philosophers have considered the relationship between aprioricity, analyticity, and necessity to be extremely close. According to Jerry Fodor, "Positivism, in particular, took it for granted that a priori truths must be necessary. Logical positivism (later and more accurately called logical empiricism) is a school of philosophy that combines Empiricism, the idea that observational evidence is . . . " However, since Kant, the distinction between analytic and synthetic propositions had slightly changed. Analytic propositions were largely taken to be "true by virtue of meanings and independently of fact", while synthetic propositions were not—one must conduct some sort of empirical investigation, looking to the world, to determine the truth-value of synthetic propositions.
However, aprioricity, analyticity, and necessity have since been more clearly separated from each other. The American philosopher Saul Kripke (1972), for example, provided strong arguments against this position. Saul Aaron Kripke (born on November 13, 1940 in Bay Shore New York) is an American philosopher and Logician now Emeritus Kripke argued that there are necessary a posteriori truths, such as the proposition that water is H2O (if it is true). According to Kripke, this statement is necessarily true (since water and H2O are the same thing, they are identical in every possible world, and truths of identity are logically necessary) and a posteriori (since it is known only through empirical investigation). Following such considerations of Kripke and others (such as Hilary Putnam), philosophers tend to distinguish more clearly the notion of aprioricity from that of necessity and analyticity. Hilary Whitehall Putnam (born July 31 1926 is an American Philosopher who has been a central figure in Western philosophy since the 1960s especially in Philosophy
Thus, the relationship between aprioricity, necessity, and analyticity is not easy to discern. However, most philosophers at least seem to agree that while the various distinctions may overlap, the notions are clearly not identical: the a priori/a posteriori distinction is epistemological, the analytic/synthetic distinction is linguistic, and the necessary/contingent distinction is metaphysical. Epistemology (from Greek επιστήμη - episteme, "knowledge" + λόγος, " Logos " or theory of knowledge Linguistics is the scientific study of Language, encompassing a number of sub-fields Metaphysics is the branch of Philosophy investigating principles of reality transcending those of any particular science