- Wikipedia:Abductive_reasoning is a form of logical inference that goes from observation to a hypothesis that accounts for the reliable data (observation) and seeks to explain relevant evidence. The American philosopher Charles Sanders Peirce (1839–1914) first introduced the term as "guessing". Peirce said that to abduce a hypothetical explanation a from an observed surprising circumstance b is to surmise that a may be true because then b would be a matter of course. Thus, to abduce a from b involves determining that a is sufficient (or nearly sufficient), but not necessary, for b.
-  Peirce, C. S. "On the Logic of drawing History from Ancient Documents especially from Testimonies" (1901), Collected Papers v. 7, paragraph 219.
- "PAP" ["Prolegomena to an Apology for Pragmatism"], MS 293 c. 1906, New Elements of Mathematics v. 4, pp. 319-320.
- A Letter to F. A. Woods (1913), Collected Papers v. 8, paragraphs 385-388.
- (See under "Abduction" and "Retroduction" at Commens Dictionary of Peirce's Terms.)
-  Peirce, C. S. (1903), Harvard lectures on pragmatism, Collected Papers v. 5, paragraphs 188–189.
Author: Jon Awbrey
- Peirce's 1870 Logic Of Relatives Peirce's text employs lower case letters for logical terms of general reference and upper case letters for logical terms of individual reference. General terms fall into types, for example, absolute terms, dyadic relative terms, or higher adic relative terms, and Peirce employs different typefaces to distinguish these. The following Tables indicate the typefaces that are used in the text below for Peirce's examples of general terms
- Absolute Terms (Monadic Relatives)
- Simple Relative Terms (Dyadic Relatives)
- Conjugative Terms (Higher adic Relatives)
- Peirce's law is a formula in propositional calculus that is commonly expressed in the following form:
Peirce's law holds in classical propositional calculus, but not in intuitionistic propositional calculus. The precise axiom system that one chooses for classical propositional calculus determines whether Peirce's law is taken as an axiom or proven as a theorem.
- Peirce's Logic Of Information I've been meaning to get back to Peirce's theory of information, because I believe that it contains a yet-to-be-tapped potential for many current issues, though it would take just a little bit of drilling to exploit its resources to the fullest that we can.
- See: Logic -- Inquiry. Pragmatic maxim, also known as the maxim of pragmatism or the maxim of pragmaticism, is a maxim of logic formulated by Charles Sanders Peirce. Serving as a normative recommendation or a regulative principle in the normative science of logic, its function is to guide the conduct of thought toward the achievement of its purpose, advising the addressee on an optimal way of "attaining clearness of apprehension".
- See: Logic -- Inquiry. Relation theory This article treats relations from the perspective of combinatorics, in other words, as a subject matter in discrete mathematics, with special attention to finite structures and concrete set-theoretic constructions, many of which arise quite naturally in applications. This approach to relation theory, or the theory of relations, is distinguished from, though closely related to, its study from the perspectives of abstract algebra on the one hand and formal logic on the other.
- See: Logic -- Inquiry. Logical graph A logical graph is a graph-theoretic structure in one of the systems of graphical syntax that Charles Sanders Peirce developed for logic.
- See: Logic -- Inquiry. Differential logic is the component of logic whose object is the successful description of variation — for example, the aspects of change, difference, distribution, and diversity — in universes of discourse that are subject to logical description. In formal logic, differential logic treats the principles that govern the use of a differential logical calculus, that is, a formal system with the expressive capacity to describe change and diversity in logical universes of discourse*See: Logic -- Inquiry. Sign Relation is the basic construct in the theory of signs, also known as semeiotic or semiotics, as developed by Charles Sanders Peirce.
- See: Logic -- Inquiry. Relation reduction
- See: Logic -- Inquiry. Truth table
- See: Logic -- Inquiry. Logical matrix
- See: Logic -- Inquiry. Minimal negation operator
- See: Logic -- Inquiry. Triadic relation
- See: Logic -- Inquiry. Differential logic
- See: Logic -- Inquiry. Ampheck
- See: Logic -- Inquiry. Continuous predicate
- See: Logic -- Inquiry. Logic of relatives
- See: Logic -- Inquiry. Hypostatic abstraction
- See: Logic -- Inquiry. Semeiotic
- See: Logic -- Inquiry. Logic of information The logic of information, or the logical theory of information, considers the information content of logical signs — everything from bits to books and beyond — along the lines initially developed by Charles Sanders Peirce. In this line of development the concept of information serves to integrate the aspects of logical signs that are separately covered by the concepts of denotation and connotation, or, in roughly equivalent terms, by the concepts of extension and comprehension.
- See: Logic -- Inquiry. Dynamics of inquiry
"Every mind which passes from doubt to belief must have ideas which follow after one another in time. Every mind which reasons must have ideas which not only follow after others but are caused by them. Every mind which is capable of logical criticism of its inferences, must be aware of this determination of its ideas by previous ideas. (Peirce, "On Time and Thought", CE 3, 68–69.)