The notion of the general purpose computer that came from this work was of fundamental importance to the designers of the computer machinery in the s. In the s and s, researchers predicted that when human knowledge could be expressed using logic with mathematical notation , it would be possible to create a machine that mimics the problem-solving skills of a human being. This was more difficult than expected because of the complexity of human reasoning. In the summer of , John McCarthy , Marvin Minsky , Claude Shannon and Nathan Rochester organized a conference on the subject of what they called " artificial intelligence " a term coined by McCarthy for the occasion.
Newell and Simon proudly presented the group with the Logic Theorist and were somewhat surprised when the program received a lukewarm reception.
Formation-rules 2. Grice, from whom I have never ceased to learn about logic since he was my tutor in the subject; and to Professor Gilbert Ryle, Mr. Editorial team. Copeland Oxford University, Copeland Oxford University, Just a moment while we sign you in to your Goodreads account. Strawson, Introduction to Logical Theory.
In logic programming , a program consists of a set of axioms and rules. Logic programming systems such as Prolog compute the consequences of the axioms and rules in order to answer a query. Today, logic is extensively applied in the field of artificial intelligence, and this field provide a rich source of problems in formal and informal logic.
Argumentation theory is one good example of how logic is being applied to artificial intelligence. Furthermore, computers can be used as tools for logicians. For example, in symbolic logic and mathematical logic, proofs by humans can be computer-assisted. Using automated theorem proving , the machines can find and check proofs, as well as work with proofs too lengthy to write out by hand.
The logics discussed above are all " bivalent " or "two-valued"; that is, they are most naturally understood as dividing propositions into true and false propositions. Non-classical logics are those systems that reject various rules of Classical logic. Hegel developed his own dialectic logic that extended Kant 's transcendental logic but also brought it back to ground by assuring us that "neither in heaven nor in earth, neither in the world of mind nor of nature, is there anywhere such an abstract 'either—or' as the understanding maintains.
Whatever exists is concrete, with difference and opposition in itself". In , Nicolai A. Vasiliev extended the law of excluded middle and the law of contradiction and proposed the law of excluded fourth and logic tolerant to contradiction. Logics such as fuzzy logic have since been devised with an infinite number of "degrees of truth", represented by a real number between 0 and 1. Intuitionistic logic was proposed by L.
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Brouwer as the correct logic for reasoning about mathematics, based upon his rejection of the law of the excluded middle as part of his intuitionism. Brouwer rejected formalization in mathematics, but his student Arend Heyting studied intuitionistic logic formally, as did Gerhard Gentzen.
Intuitionistic logic is of great interest to computer scientists, as it is a constructive logic and sees many applications, such as extracting verified programs from proofs and influencing the design of programming languages through the formulae-as-types correspondence. Modal logic is not truth conditional, and so it has often been proposed as a non-classical logic. However, modal logic is normally formalized with the principle of the excluded middle, and its relational semantics is bivalent, so this inclusion is disputable. What is the epistemological status of the laws of logic?
What sort of argument is appropriate for criticizing purported principles of logic? In an influential paper entitled " Is Logic Empirical? Quine , argued that in general the facts of propositional logic have a similar epistemological status as facts about the physical universe, for example as the laws of mechanics or of general relativity , and in particular that what physicists have learned about quantum mechanics provides a compelling case for abandoning certain familiar principles of classical logic: if we want to be realists about the physical phenomena described by quantum theory, then we should abandon the principle of distributivity , substituting for classical logic the quantum logic proposed by Garrett Birkhoff and John von Neumann.
Another paper of the same name by Michael Dummett argues that Putnam's desire for realism mandates the law of distributivity. In this way, the question, "Is Logic Empirical? The notion of implication formalized in classical logic does not comfortably translate into natural language by means of "if Eliminating this class of paradoxes was the reason for C. Lewis 's formulation of strict implication , which eventually led to more radically revisionist logics such as relevance logic.
The second class of paradoxes involves redundant premises, falsely suggesting that we know the succedent because of the antecedent: thus "if that man gets elected, granny will die" is materially true since granny is mortal, regardless of the man's election prospects. Such sentences violate the Gricean maxim of relevance, and can be modelled by logics that reject the principle of monotonicity of entailment , such as relevance logic. Hegel was deeply critical of any simplified notion of the law of non-contradiction. It was based on Gottfried Wilhelm Leibniz 's idea that this law of logic also requires a sufficient ground to specify from what point of view or time one says that something cannot contradict itself.
A building, for example, both moves and does not move; the ground for the first is our solar system and for the second the earth. In Hegelian dialectic, the law of non-contradiction, of identity, itself relies upon difference and so is not independently assertable. Closely related to questions arising from the paradoxes of implication comes the suggestion that logic ought to tolerate inconsistency.
Relevance logic and paraconsistent logic are the most important approaches here, though the concerns are different: a key consequence of classical logic and some of its rivals, such as intuitionistic logic , is that they respect the principle of explosion , which means that the logic collapses if it is capable of deriving a contradiction.
Graham Priest , the main proponent of dialetheism , has argued for paraconsistency on the grounds that there are in fact, true contradictions. The philosophical vein of various kinds of skepticism contains many kinds of doubt and rejection of the various bases on which logic rests, such as the idea of logical form, correct inference, or meaning, typically leading to the conclusion that there are no logical truths.
This is in contrast with the usual views in philosophical skepticism , where logic directs skeptical enquiry to doubt received wisdoms, as in the work of Sextus Empiricus. Friedrich Nietzsche provides a strong example of the rejection of the usual basis of logic: his radical rejection of idealization led him to reject truth as a " Innumerable beings who made inferences in a way different from ours perished".
This position held by Nietzsche however, has come under extreme scrutiny for several reasons. From Wikipedia, the free encyclopedia. This article is about the systematic study of the form of arguments. For other uses, see Logic disambiguation. Study of inference and truth. Plato Kant Nietzsche. Buddha Confucius Averroes. Main article: Logical form. Main article: Semantics of logic. Main article: Formal system. Main article: Logic and rationality.
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There might be a discussion about this on the talk page. May Learn how and when to remove this template message. Main article: Conceptions of logic. Main article: History of logic.
Main article: Aristotelian logic. Main article: Propositional calculus.
Main article: Predicate logic. Main article: Modal logic.
Main articles: Informal logic and Logic and dialectic. Main article: Mathematical logic. Main article: Philosophical logic. Main articles: Computational logic and Logic in computer science. Main article: Non-classical logic. Further information: Is Logic Empirical? Main article: Paradoxes of material implication. Main article: Paraconsistent logic. Philosophy portal. In Mckeon, Richard ed. The Basic Works. Modern Library. Cambridge University Press. Logic for Mathematicians. Aristotle's syllogistic from the standpoint of modern formal logic 2nd ed.
Oxford University Press. Freddoso and H. Schuurman, St Augustine's Press , p. The Logic Book Fifth ed. Introduction to Mathematical Logic. Van Nostrand.