Portal:Logic
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Logic (from Classical Greek λόγος logos; meaning 'speech/word') is the study of the principles and criteria of valid inference and demonstration. As a formal science, logic investigates and classifies the structure of statements and arguments, both through the study of formal systems of inference and through the study of arguments in natural language. The field of logic ranges from core topics such as the study of fallacies and paradoxes, to specialized analysis of reasoning using probability and to arguments involving causality. Logic is also commonly used today in argumentation theory. [1] Traditionally, logic is studied as a branch of philosophy, one part of the classical trivium, which consisted of grammar, logic, and rhetoric. Since the mid-nineteenth century formal logic has been studied in the context of the foundations of mathematics. In 1903 Bertrand Russell and Alfred North Whitehead attempted to establish logic as the cornerstone of mathematics formally with the publication of Principia Mathematica. However, the system of Principia is no longer much used, having been largely supplanted by set theory. The development of formal logic and its implementation in computing machinery is the foundation of computer science. |
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.
Together with Plato and Socrates (Plato's teacher), Aristotle is one of the most important founding figures in Western philosophy. He was the first to create a comprehensive system of Western philosophy, encompassing morality and aesthetics, logic and science, politics and metaphysics. Aristotle's views on the physical sciences profoundly shaped medieval scholarship, and their influence extended well into the Renaissance, although they were ultimately replaced by Newtonian Physics. In the biological sciences, some of his observations were confirmed to be accurate only in the nineteenth century. His works contain the earliest known formal study of logic, which was incorporated in the late nineteenth century into modern formal logic. In metaphysics, Aristotelianism had a profound influence on philosophical and theological thinking in the Islamic and Jewish traditions in the Middle Ages, and it continues to influence Christian theology, especially Eastern Orthodox theology, and the scholastic tradition of the Roman Catholic Church. All aspects of Aristotle's philosophy continue to be the object of active academic study today.
- ...that the Law of noncontradiction is the same as the Law of contradiction?
- ...that nand alone or nor alone make a functionally complete set of logical operators?
- ...that according to the continuum hypothesis, there is no cardinal number in between aleph null and the cardinality of the continuum?
- ...that all 24 valid syllogistic forms have names like 'Camestrop' and 'Felapton'?
- ...that if a statement P implies another statement Q, and a third statement R also implies Q, and either P or R is true; then Q has to be true?
- ...that the dunce hat was named after a logician?
- ...that the collective noun for a group of logicians is a "sequitur of logicians"
Requested articles: Affirming the disjunct • Alethic • Ambiguous middle term • Anonymous authority • Anti-Procreation Movement • Appeal to classical allusions • Appeal to law • Appeal to written law • Argument by example • Archimedean Fulcrum • Asserting an alternative • Bad reasons fallacy • Cartesian logic • Common thread reasoning • Complex cause • Conjunctive forks • Converting a conditional • Doctrine of Unexpected Consequences • Dream logic • Equivocity • Exclusive premises • 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 consequent • Fallacy of the disjunctive syllogism • Fallacy of the propositional logic • Four term fallacy • Free time (fallacy) • Futurist extrapolation • Ganto's Ax • Heads in the sand critique • Ignoring common cause • Illicit major premise • Illicit minor premise • Illicit process • Illicit quantifier shift • 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 • List of invalid argument forms • Logical notation • Meinongian arguments • Mereological arguments • Missing the point • Negating antecedent and conseqent • Negative conclusion from affirmative premises • Neutrality Schmeutrality • One-sidedness • Open Block Logic • Oppositional logic • Perfectly rigorous • Physiological Egoism • Plurivocity • Positive conclusion from negative premises • Postmodern mathematics • Prejudicial language • Pseudorefutation • Quantifier shift fallacy • Quote-name • Repetition (fallacy) • Science fiction moralizing • Significant difference reasoning • Slothful induction • Some are/some are not • Sublime experience • Superalternation • Swiftian logic • Tendentious appeal to possibilities • truth-apt • Truthmapping • Two negative premises • Unwarranted contrast • Upwards inherited • Van Gogh fallacy • Volitive • Weaseler • Woodward, John Arrington
