# Portal:Logic

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## Logic

Logic (from the Ancient Greek: λογική, translit. logikḗ) is the systematic study of the form of valid inference, and the most general laws of truth. A valid inference is one where there is a specific relation of logical support between the assumptions of the inference and its conclusion. In ordinary discourse, inferences may be signified by words such as therefore, hence, ergo, and so on.

There is no universal agreement as to the exact scope and subject matter of logic (see § Rival conceptions, below), but it has traditionally included the classification of arguments, the systematic exposition of the 'logical form' common to all valid arguments, the study of proof and inference, including paradoxes and fallacies, and the study of syntax and semantics. Historically, logic has been studied in philosophy (since ancient times) and mathematics (since the mid-19th century), and recently logic has been studied in computer science, linguistics, psychology, and other fields.

## Selected article

The history of logic is the study of the development of the science of valid inference (logic). While many cultures have employed intricate systems of reasoning, and logical methods are evident in all human thought, an explicit analysis of the principles of reasoning was developed only in three traditions: those of China, India, and Greece. Of these, only the treatment of logic descending from the Greek tradition, particularly Aristotelian logic, found wide application and acceptance in science and mathematics. The Greek tradition was further developed by Islamic logicians and then medieval European logicians. Not until the 19th century does the next great advance in logic arise, with the development of symbolic logic by George Boole and its subsequent development into formal calculable logical systems by Gottlob Frege and set theorists such as Georg Cantor and Giuseppe Peano, ushering in the Information Age.

Logic was known as 'dialectic' or 'analytic' in Ancient Greece. The word 'logic' (from the Greek logos, meaning discourse or sentence) does not appear in the modern sense until the commentaries of Alexander of Aphrodisias, writing in the third century A.D.

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## Selected biography

Ramon Llull (Catalan: [rəˈmoɲ ˈʎuʎ]; ca. 1232[1] – ca. 1315) (Anglicised Raymond Lully, Raymond Lull; in Latin Raimundus or Raymundus Lullus or Lullius) was a Majorcan writer and philosopher, logician and a Franciscan tertiary. He wrote the first major work of Catalan literature. Recently-surfaced manuscripts show him to have anticipated by several centuries prominent work on elections theory. He is sometimes considered a pioneer of computation theory, especially given his influence on Gottfried Leibniz. Llull is well known also as a glossator of Roman Law.

Within the Franciscan Order, he is honored as a martyr. He was beatified in 1857 by Pope Pius IX and his feast day was assigned to 30 June and is celebrated by the Third Order of St. Francis.

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## Things to do

 Here are some tasks awaiting attention: Article requests : Anonymous authority  • Anti-Procreation Movement  • Appeal to classical allusions  • Archimedean Fulcrum  • Asserting an alternative  • Bad reasons fallacy  • Cartesian logic  • Common thread reasoning  • Conjunctive forks  • Converting a conditional  • Doctrine of Unexpected Consequences  • Dream logic  • Equivocity  • Fallacy of assuming a common cause  • Fallacy of biased generalization  • Conflicting conditions  • Failure to elucidate  • Too broad  • Too narrow  • Fallacies of distraction  • Fallacies of explanation  • Limited depth  • Limited scope  • Non-support  • Subverted support  • Untestability  • Fallacy of personal preference assumptions  • Fallacy of quantificational logic  • Fallacy of reverse causation  • Fallacy of the alternative syllogism  • Fallacy of the disjunctive syllogism  • Fallacy of the propositional logic  • Free time (fallacy)  • Futurist extrapolation  • Heads in the sand critique  • Ignoring common cause  • Illicit process  • Improper disjunctive syllogism  • Improper transposition  • Inferring from a metaphor  • Intuitionistic modal logic  • Jactication  • Kicking the problem upstairs  • Lennon/McCartney fallacy  • Liminocentricity  • List of valid argument forms Done  • List of invalid argument forms  • Logical notation  • Meinongian arguments  • Mereological arguments  • Negating antecedent and consequent  • Neutrality Schmeutrality  • One-sidedness  • Open Block Logic  • Oppositional logic  • Perfectly rigorous  • Physiological Egoism  • Plurivocity  • Postmodern mathematics  • Prejudicial language  • Pseudorefutation  • Quote-name  • Repetition (fallacy)  • Science fiction moralizing  • Significant difference reasoning  • Some are/some are not  • Sublime experience  • Superalternation  • Swiftian logic  • Tendentious appeal to possibilities  • truth-apt  • Truthmapping  • Unwarranted contrast  • Upwards inherited  • Volitive  • Weaseler  • John Arrington WoodwardOther : Add links to this portal by placing {{Portal|Logic}} in the See also sections of relevant articles

## References

1. ^ Born 1232 per Mark D. Johnston in Routledge Encyclopedia of Philosophy. London: Routledge, 1998. Older sources (such as versions of Encyclopædia Britannica at least up to 1955) give 1235; the current Britannica gives 1232/33.

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