Concept
Square of opposition
Related concepts (15)
Logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or logical truths. It studies how conclusions follow from premises due to the structure of arguments alone, independent of their topic and content. Informal logic is associated with informal fallacies, critical thinking, and argumentation theory. It examines arguments expressed in natural language while formal logic uses formal language.
Organon
The Organon (Ὄργανον, meaning "instrument, tool, organ") is the standard collection of Aristotle's six works on logical analysis and dialectic. The name Organon was given by Aristotle's followers, the Peripatetics, who maintained against the Stoics that Logic was "an instrument" of Philosophy. The term "organon" is neither found in Aristotle, nor does it occur in the writings of Plato. The book, according to M. Barthélemy St.
Term logic
In logic and formal semantics, term logic, also known as traditional logic, syllogistic logic or Aristotelian logic, is a loose name for an approach to formal logic that began with Aristotle and was developed further in ancient history mostly by his followers, the Peripatetics. It was revived after the third century CE by Porphyry's Isagoge. Term logic revived in medieval times, first in Islamic logic by Alpharabius in the tenth century, and later in Christian Europe in the twelfth century with the advent of new logic, remaining dominant until the advent of predicate logic in the late nineteenth century.
Categorical proposition
In logic, a categorical proposition, or categorical statement, is a proposition that asserts or denies that all or some of the members of one category (the subject term) are included in another (the predicate term). The study of arguments using categorical statements (i.e., syllogisms) forms an important branch of deductive reasoning that began with the Ancient Greeks. The Ancient Greeks such as Aristotle identified four primary distinct types of categorical proposition and gave them standard forms (now often called A, E, I, and O).
Logical hexagon
In philosophical logic, the logical hexagon (also called the hexagon of opposition) is a conceptual model of the relationships between the truth values of six statements. It is an extension of Aristotle's square of opposition. It was discovered independently by both Augustin Sesmat and Robert Blanché. This extension consists in introducing two statements U and Y. Whereas U is the disjunction of A and E, Y is the conjunction of the two traditional particulars I and O.
Obversion
In traditional logic, obversion is a "type of immediate inference in which from a given proposition another proposition is inferred whose subject is the same as the original subject, whose predicate is the contradictory of the original predicate, and whose quality is affirmative if the original proposition's quality was negative and vice versa". The quality of the inferred categorical proposition is changed but the truth value is the same to the original proposition.
Philosophical logic
Understood in a narrow sense, philosophical logic is the area of logic that studies the application of logical methods to philosophical problems, often in the form of extended logical systems like modal logic. Some theorists conceive philosophical logic in a wider sense as the study of the scope and nature of logic in general. In this sense, philosophical logic can be seen as identical to the philosophy of logic, which includes additional topics like how to define logic or a discussion of the fundamental concepts of logic.
Logical cube
In the system of Aristotelian logic, the logical cube is a diagram representing the different ways in which each of the eight propositions of the system is logically related ('opposed') to each of the others. The system is also useful in the analysis of syllogistic logic, serving to identify the allowed logical conversions from one type to another.
Triangle of opposition
In the system of Aristotelian logic, the triangle of opposition is a diagram representing the different ways in which each of the three propositions of the system is logically related ('opposed') to each of the others. The system is also useful in the analysis of syllogistic logic, serving to identify the allowed logical conversions from one type to another.
Peter Abelard
Peter Abelard (ˈæbəlɑrd; Pierre Abélard; Petrus Abaelardus or Abailardus; 1079 - 21 April 1142) was a medieval French scholastic philosopher, leading logician, theologian, poet, composer and musician. In philosophy he is celebrated for his logical solution to the problem of universals via nominalism and conceptualism and his pioneering of intent in ethics. Often referred to as the "Descartes of the twelfth century", he is considered a forerunner of Rousseau, Kant, and Spinoza.