Definition of logic 1.reasoned and reasonable judgment; "it made a certain kind of logic" 2.a system of reasoning 3.the principles that guide reasoning within a given field or situation; "economic logic requires it"; "by the logic of war" 4.the branch of philosophy that analyzes inference Syllogism In logic, a syllogism is a valid, three-step argument of the form: [Statement A]. [Statement B]. Therefore, [Statement C]. Forms of syllogism: Categorical syllogism[?] Disjunctive syllogism Hypothetical syllogism add list of other syllogism forms here The Aristotle wrote the classic "Barbara" syllogism: If all humans (B's) are mortal (A), and all Greeks (C's) are humans (B's), then all Greeks (C's) are mortal (A). That is, Men die. Socrates is a man. Socrates will die. Metaphor, in contrast, resembles a form of syllogism called Affirming the Consequent: Grass dies. Men die. Men are grass. A Barbara syllogism involves Grammar and Logical Types; it has a subject and a predicate. Affirming the Consequent, the basis of metaphor, is grammatically symmetrical: it equates two predicates. This form of syllogism is logically invalid. this is a stub article Epagoge are weak syllogisms that rely on inductive reasoning. Proposition In modern logic, a proposition is what is asserted as the result of uttering asentence. In other words, it is the meaning of the sentence, rather than the sentence itself. Different sentences can express the same proposition, if they have the same meaning. In Aristotelian logic a proposition is a particular kind of sentence, one which affirms or denies a predicate of a subject, and thus asserts something true or false. Propositions fall unto three classes. Universal propositions[?], such as "all men are mortal" affirm or deny the predicate mortal of the "whole of" their subject, i.e. the entire class of things that the subject applies to. Particular propositions[?], such as "some men are mortal" affirm or deny the predicate of only part of the subject. Singular propositions[?], such as "Socrates is a man" present a difficulty. Usually they were regarded as a universal proposition, since they can only be true of a single object, and thus true of all the objects (one) they possibly can be true of. On the other hand, "they are in truth the most limited kind of particular propositions". Argument An argument is a disagreement between two or more people, but it can also be a statement backed by evidence, like your argument that your school doesn't need a dress code. Argument comes from the 14th century French word of the same spelling, meaning, "statements and reasoning in support of a proposition." An argument can be a fact used as evidence to show that something is true, like a study that shows exercise improves certain health conditions an argument for being more active. Argument also means "a discussion between people who have contrary views." Definition of premise 1.a statement that is assumed to be true and from which a conclusion can be drawn; "on the assumption that he has been injured we can infer that he will not to play" 2.take something as preexisting and given 3.furnish with a preface or introduction; "She always precedes her lectures with a joke"; "He prefaced his lecture with a critical remark about the institution" 4.set forth beforehand, often as an explanation; "He premised these remarks so that his readers might understand"

Definition of conclusion 1.the act of making up your mind about something; "the burden of decision was his"; "he drew his conclusions quickly" 2.the act of ending something; "the termination of the agreement" 3.an intuitive assumption; "jump to a conclusion" 4.a position or opinion or judgment reached after consideration; "a decision unfavorable to the opposition"; "his conclusion took the evidence into account"; "satisfied with the panel''s determination" 5.the last section of a communication; "in conclusion I want to say..." 6.the proposition arrived at by logical reasoning (such as the proposition that must follow from the major and minor premises of a syllogism) 7.a final settlement; "the conclusion of a business deal"; "the conclusion of the peace treaty" 8.event whose occurrence ends something; "his death marked the ending of an era"; "when these final episodes are broadcast it will be the finish of the show" 9.the temporal end; the concluding time; "the stopping point of each round was signaled by a bell"; "the market was up at the finish"; "they were playing better at the close of the season" Definition of opposition 1.the action of opposing something that you disapprove or disagree with; "he encountered a general feeling of resistance from many citizens"; "despite opposition from the newspapers he went ahead" 2.the act of opposing groups confronting each other; "the government was not ready for a confrontation with the unions"; "the invaders encountered stiff opposition" 3.a body of people united in opposing something 4.a political party opposed to the party in power and prepared to replace it if elected; "Her Majesty''s loyal opposition" 5.an armed adversary (especially a member of an opposing military force); "a soldier must be prepared to kill his enemies" 6.a contestant that you are matched against 7.a direction opposite to another 8.the relation between opposed entities Definition of inference 1.the reasoning involved in drawing a conclusion or making a logical judgment on the basis of circumstantial evidence and prior conclusions rather than on the basis of direct observation Deductive reasoning Redirected from Deductive logic Deductive reasoning is the process of reasoning from the general to the specific. Deductive reasoning is supported by deductive logic, for example: From general propositions: All ravens are black birds. For every action, there is an equal and opposite re-action To specific propositions such as: This bird is black, therefore it is a raven. This billiard ball will move when struck with a cue. In contrast to inductive reasoning, the conclusions of deductive reasoning are as valid as the initial assumption. Deductive reasoning was first described by the ancient Greek philosophers such as Aristotle. Inductive reasoning Inductive reasoning is the process of reasoning from the specific to the general. Inductive reasoning is supported by inductive logic, for example: From specific propositions such as: This raven is a black bird. A billiard ball moves when struck with a cue. To general propositions: All ravens are black birds. For every action, there is an equal and opposite re-action In contrast to deductive reasoning, conclusions arrived at by inductive reasoning do not necessarily have the same validity as the initial assumptions. Inductive logic expresses the truth-value of its inferences in terms of probability rather than necessity. The nature of inductive reasoning, with examples, is discussed further at cogency. Philosophers since at least David Hume recognized a significant distinction between two kinds of statements, later called by Immanuel Kant "analytic" and "synthetic." Analytic truths, such as "All bachelors are unmarried men," or "Human beings are two-legged animals" are supposed to be true by virtue of the meanings of the words alone. Synthetic statements, such as "All ravens are black," or "All men are mortal," are true if at all only by virtue of some facts about the world. One has to discover that men die and ravens are black. W. V. Quine debunked this distinction in his influential essay Two Dogmas of Empiricism and postulated that any empirical evidence that seems to falsify anyparticular theory can always be accommodated by the theory in question. Quine's observation reflects the problem of inductive logic formally addressed first by David Hume. Hume's psychological theory of inductive logic, simple enumerative induction, or induction by repetition, was challenged by Karl PopperPopper's challenge was later discredited by the Quine-Duhem thesis stated above. Some consider that the scientific method relies on inductive reasoning. However, many researchers use hypothetico-deductive approaches derived from the work of Karl Popper. The validity of some forms of such inductive and deductive reasoning is formally described by statistics. Reasoning The act of using reason to derive a conclusion from certain premises. In general, a distinction is made between reasoning from the general to the particular (calleddeductive reasoning) and reasoning from the particular to the general (calledinductive reasoning). Both types of reasoning are of interest to such disciplines as philosophy and psychology. A priori and a posteriori knowledge Western philosophers have distinguished between two kinds of knowledge: a priori knowledge and a posteriori knowledge. A priori knowledge is knowledge gained or justified by reason alone, without the direct or indirect influence of experience (here, experience usually means observation of the world through sense perception.) A posteriori knowledge is any other sort of knowledge, viz. knowledge the attainment or justification of which requires reference to experience. This is also called empirical knowledge. One of the fundamental questions in epistemology is whether there is any non-trivial a priori knowledge. Generally speaking rationalists believe that there is, while empiricists believe that all knowledge is ultimately derived from some kind of external experience. The fields of knowledge most often suggested as having a priori status are logicand mathematics, which deal primarily with abstract, formal objects. Empiricists have traditionally denied that even these fields could be a priori knowledge. Two common arguments are that these sorts of knowledge can only be derived from experience (as John Stuart Mill argued), and that they do not constitute "real" knowledge (as David Hume argued). Note that discussions of a priori and a posteriori knowledge almost always concern propositional knowledge, or, roughly, "knowledge that". The authors don't know if the distinction has found its way into discussions of other kinds of knowledge, e.g. "knowledge how". Other Notes: Argument From Wikipedia, the free encyclopedia This article is about the subject as it is studied in logic and philosophy. For other uses, see Argument (disambiguation). In logic and philosophy, an argument is a series of statements typically used to persuade someone of something or to present reasons for accepting a conclusion.[1][2] The general form of an argument in a natural language is that of premises (typically in the form of propositions, statements or sentences) in support of a claim: the conclusion.[3][4][5]The structure of some arguments can also be set out in a formal language, and formally defined "arguments" can be made independently of natural language arguments, as in math, logic, and computer science. In a typical deductive argument, the premises are meant to provide a guarantee of the truth of the conclusion, while in an inductive argument, they are thought to provide reasons supporting the conclusion's probable truth.[6] The standards for evaluating non-deductive arguments may rest on different or additional criteria than truth, for example, the persuasiveness of so-called "indispensability claims" in transcendental arguments,[7] the quality of hypotheses in retroduction, or even the disclosure of new possibilities for thinking and acting.[8] The standards and criteria used in evaluating arguments and their forms of reasoning are studied in logic.[9] Ways of formulating arguments effectively are studied in rhetoric(see also: argumentation theory). An argument in a formal language shows the logical form of the symbolically represented or natural language arguments obtained by itsinterpretations.