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Dilemma
A dilemma () is a problem offering two possibilities, neither of which is unambiguously acceptable or preferable. The possibilities are termed the ''horns'' of the dilemma, a clichéd usage, but distinguishing the dilemma from other kinds of predicament as a matter of usage. Terminology The term ''dilemma'' is attributed by Gabriel Nuchelmans to Lorenzo Valla in the 15th century, in later versions of his logic text traditionally called ''Dialectica''. Valla claimed that it was the appropriate Latin equivalent of the Greek ''dilemmaton''. Nuchelmans argued that his probable source was a logic text of of George of Trebizond. He also concluded that Valla had reintroduced to the Latin West a type of argument that had fallen into disuse. Valla's neologism did not immediately take hold, preference being given to the established Latin term ''complexio'', used by Cicero, with ''conversio'' applied to the upsetting of dilemmatic reasoning. With the support of Juan Luis Vives, how ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
False Dichotomy
A false dilemma, also referred to as false dichotomy or false binary, is an informal fallacy based on a premise that erroneously limits what options are available. The source of the fallacy lies not in an invalid form of inference but in a false premise. This premise has the form of a disjunction, disjunctive claim: it asserts that one among a number of alternatives must be true. This disjunction is problematic because it oversimplifies the choice by excluding viable alternatives, presenting the viewer with only two absolute choices when, in fact, there could be many. False dilemmas often have the form of treating two contraries, which may both be false, as contradictories, of which one is necessarily true. Various inferential schemes are associated with false dilemmas, for example, the constructive dilemma, the destructive dilemma or the disjunctive syllogism. False dilemmas are usually discussed in terms of deductive reasoning, deductive arguments, but they can also occur as de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propositional Logic
The propositional calculus is a branch of logic. It is also called propositional logic, statement logic, sentential calculus, sentential logic, or sometimes zeroth-order logic. Sometimes, it is called ''first-order'' propositional logic to contrast it with System F, but it should not be confused with first-order logic. It deals with propositions (which can be true or false) and relations between propositions, including the construction of arguments based on them. Compound propositions are formed by connecting propositions by logical connectives representing the truth functions of conjunction, disjunction, implication, biconditional, and negation. Some sources include other connectives, as in the table below. Unlike first-order logic, propositional logic does not deal with non-logical objects, predicates about them, or quantifiers. However, all the machinery of propositional logic is included in first-order logic and higher-order logics. In this sense, propositional logi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Destructive Dilemma
Destructive dilemmaMoore and Parker is the name of a valid rule of inference of propositional logic. It is the inference that, if ''P'' implies ''Q'' and ''R'' implies ''S'' and either ''Q'' is false or ''S'' is false, then either ''P'' or ''R'' must be false. In sum, if two conditionals are true, but one of their consequents is false, then one of their antecedents has to be false. ''Destructive dilemma'' is the disjunctive version of ''modus tollens''. The disjunctive version of ''modus ponens'' is the constructive dilemma. The destructive dilemma rule can be stated: :\frac where the rule is that wherever instances of "P \to Q", "R \to S", and "\neg Q \lor \neg S" appear on lines of a proof, "\neg P \lor \neg R" can be placed on a subsequent line. Formal notation The ''destructive dilemma'' rule may be written in sequent notation: : (P \to Q), (R \to S), (\neg Q \lor \neg S) \vdash (\neg P \lor \neg R) where \vdash is a metalogical symbol meaning that \neg P \lor \neg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constructive Dilemma
Constructive dilemmaCopi and Cohen is a valid rule of inference of propositional logic. It is the inference that, if ''P'' implies ''Q'' and ''R'' implies ''S'' and either ''P'' or ''R'' is true, then either ''Q or S'' has to be true. In sum, if two conditionals are true and at least one of their antecedents is, then at least one of their consequents must be too. ''Constructive dilemma'' is the disjunctive version of modus ponens, whereas destructive dilemma is the disjunctive version of ''modus tollens''. The constructive dilemma rule can be stated: :\frac where the rule is that whenever instances of "P \to Q", "R \to S", and "P \lor R" appear on lines of a proof, "Q \lor S" can be placed on a subsequent line. Formal notation The ''constructive dilemma'' rule may be written in sequent notation: : (P \to Q), (R \to S), (P \lor R) \vdash (Q \lor S) where \vdash is a metalogical symbol meaning that Q \lor S is a syntactic consequence of P \to Q, R \to S, and P \lor R in so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lorenzo Valla
Lorenzo Valla (; also latinized as Laurentius; 1 August 1457) was an Italian Renaissance humanist, rhetorician, educator and scholar. He is best known for his historical-critical textual analysis that proved that the Donation of Constantine was a forgery, therefore attacking and undermining the presumption of temporal power claimed by the papacy. Lorenzo is sometimes seen as a precursor of the Reformation. Life Valla was born in Rome, with a family background of Piacenza; his father, Luciave della Valla, was a lawyer who worked in the Papal Curia. He was educated in Rome, attending the classes of teachers including Leonardo Bruni and Giovanni Aurispa, from whom he learned Latin and Greek. He is thought otherwise to have been largely self-taught. Bruni was a papal secretary; Melchior Scrivani, Valla's uncle, was another. But Valla had caused offence, to Antonio Loschi, by championing the rhetorician Quintilian in an early work. In 1431, he was ordained as a priest; the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excluded Middle
In logic, the law of excluded middle or the principle of excluded middle states that for every proposition, either this proposition or its negation is true. It is one of the three laws of thought, along with the law of noncontradiction and the law of identity; however, no system of logic is built on just these laws, and none of these laws provides inference rules, such as modus ponens or De Morgan's laws. The law is also known as the law/principle of the excluded third, in Latin ''principium tertii exclusi''. Another Latin designation for this law is ''tertium non datur'' or "no third ossibilityis given". In classical logic, the law is a tautology. In contemporary logic the principle is distinguished from the semantical principle of bivalence, which states that every proposition is either true or false. The principle of bivalence always implies the law of excluded middle, while the converse is not always true. A commonly cited counterexample uses statements unprovable now, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cicero
Marcus Tullius Cicero ( ; ; 3 January 106 BC – 7 December 43 BC) was a Roman statesman, lawyer, scholar, philosopher, orator, writer and Academic skeptic, who tried to uphold optimate principles during the political crises that led to the establishment of the Roman Empire. His extensive writings include treatises on rhetoric, philosophy and politics. He is considered one of Rome's greatest orators and prose stylists and the innovator of what became known as "Ciceronian rhetoric". Cicero was educated in Rome and in Greece. He came from a wealthy municipal family of the Roman equestrian order, and served as consul in 63 BC. He greatly influenced both ancient and modern reception of the Latin language. A substantial part of his work has survived, and he was admired by both ancient and modern authors alike. Cicero adapted the arguments of the chief schools of Hellenistic philosophy in Latin and coined a large portion of Latin philosophical vocabulary via ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gabriel Nuchelmans
Gabriel Nuchelmans (15 May 1922, Oud Gastel – 6 August 1996, Wassenaar) was a Dutch philosopher, who focused on the history of philosophy as well as on logic and the philosophy of language more in particular. Biography After completing high school at the Episcopal School of Roermond, Nuchelmans studied at the Catholic University of Nijmegen, where he also earned his PhD in 1950. During the PhD he spent a year in Freiburg/Switzerland with Olof Gigon and Joseph Maria Bocheński. In 1947/48 he attended courses by Alfred Ayer and Stuart Hampshire, at University College London. He also heard, at the London School of Economics, Karl Popper and J.O.Wisdom. After admission to the PhD Nuchelmans taught for fourteen years Latin and Greek in Velsen. From 1964 he taught Ancient Philosophy and Analytic Philosophy and its History at the Philosophical Institute of the University of Leiden until his retirement on 10 September 1987. In this occasion a volume of essays (Logos and Pragma) was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greeks
Greeks or Hellenes (; , ) are an ethnic group and nation native to Greece, Greek Cypriots, Cyprus, Greeks in Albania, southern Albania, Greeks in Turkey#History, Anatolia, parts of Greeks in Italy, Italy and Egyptian Greeks, Egypt, and to a lesser extent, other countries surrounding the Eastern Mediterranean and Black Sea. They also form a significant Greek diaspora, diaspora (), with many Greek communities established around the world.. Greek colonies and communities have been historically established on the shores of the Mediterranean Sea and Black Sea, but the Greek people themselves have always been centered on the Aegean Sea, Aegean and Ionian Sea, Ionian seas, where the Greek language has been spoken since the Bronze Age.. Until the early 20th century, Greeks were distributed between the Greek peninsula, the western coast of Asia Minor, the Black Sea coast, Cappadocia in central Anatolia, Egypt, the Balkans, Cyprus, and Constantinople. Many of these regions coincided to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rules Of Inference
Rules of inference are ways of deriving conclusions from premises. They are integral parts of formal logic, serving as norms of the logical structure of valid arguments. If an argument with true premises follows a rule of inference then the conclusion cannot be false. ''Modus ponens'', an influential rule of inference, connects two premises of the form "if P then Q" and "P" to the conclusion "Q", as in the argument "If it rains, then the ground is wet. It rains. Therefore, the ground is wet." There are many other rules of inference for different patterns of valid arguments, such as '' modus tollens'', disjunctive syllogism, constructive dilemma, and existential generalization. Rules of inference include rules of implication, which operate only in one direction from premises to conclusions, and rules of replacement, which state that two expressions are equivalent and can be freely swapped. Rules of inference contrast with formal fallaciesinvalid argument forms involving lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Dilemma (BM 1945,0109
A, or a, is the first letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is '' a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version is often written in one of two forms: the double-storey and single-storey . The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English, '' a'' is the indefinite article, with the alternative form ''an''. Name In English, the name of the letter is the ''long A'' sound, pronounced . Its name in most other languages matches the letter's pronunciation in open syllables. History The earliest known ancestor of A is ''aleph''—the first letter of the Phoenician ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melissus Of Samos
Melissus of Samos (; ; ) was the third and last member of the ancient school of Eleatic philosophy, whose other members included Zeno and Parmenides. Little is known about his life, except that he was the commander of the Samian fleet in the Samian War. Melissus’s contribution to philosophy was a treatise of systematic arguments supporting Eleatic philosophy. Like Parmenides, he argued that reality is ungenerated, indestructible, indivisible, changeless, and motionless. In addition, he sought to show that reality is wholly unlimited, and infinitely extended in all directions; and since existence is unlimited, it must also be one. Life Not much information remains regarding the life of Melissus. He may have been born around 500 BC; the date of his death is unknown. The little which is known about him is mostly gleaned from a small passage in Plutarch’s ''Life of Pericles''. He was the commander of the Samian fleet in the Samian War, and defeated Pericles and the Athenian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
