Category Archives: Proof Theory

Peirce’s Law • 7

Posted on October 25, 2023 by Jon Awbrey

Equational Form (concl.) The following animation replays the steps of the proof. Reference Peirce, Charles Sanders (1885), “On the Algebra of Logic : A Contribution to the Philosophy of Notation”, American Journal of Mathematics 7 (1885), 180–202.  Reprinted (CP 3.359–403), (CE 5, 162–190). … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Peirce’s Law • 6

Posted on October 24, 2023 by Jon Awbrey

Equational Form (cont.) Using the axioms and theorems listed in the entries on logical graphs, the equational form of Peirce’s law may be proved in the following manner. Reference Peirce, Charles Sanders (1885), “On the Algebra of Logic : A … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Peirce’s Law • 5

Posted on October 23, 2023 by Jon Awbrey

Equational Form A stronger form of Peirce’s law also holds, in which the final implication is observed to be reversible, resulting in the following equivalence. The converse implication is clear enough on general principles, since holds for any proposition Representing … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Peirce’s Law • 4

Posted on October 22, 2023 by Jon Awbrey

Proof Animation The following animation replays the steps of the proof. Reference Peirce, Charles Sanders (1885), “On the Algebra of Logic : A Contribution to the Philosophy of Notation”, American Journal of Mathematics 7 (1885), 180–202.  Reprinted (CP 3.359–403), (CE 5, 162–190). Resources … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Peirce’s Law • 3

Posted on October 21, 2023 by Jon Awbrey

Graphical Proof Using the axiom set given in the articles on logical graphs, Peirce’s law may be proved in the following manner. Reference Peirce, Charles Sanders (1885), “On the Algebra of Logic : A Contribution to the Philosophy of Notation”, … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Peirce’s Law • 2

Posted on October 20, 2023 by Jon Awbrey

Graphical Representation Representing propositions in the language of logical graphs, and operating under the existential interpretation, Peirce’s law is expressed by means of the following formal equivalence or logical equation. Reference Peirce, Charles Sanders (1885), “On the Algebra of Logic … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Peirce’s Law • 1

Posted on October 19, 2023 by Jon Awbrey

A Curious Truth of Classical Logic Peirce’s law is a propositional calculus formula which states a non‑obvious truth of classical logic and affords a novel way of defining classical propositional calculus. Introduction Peirce’s law is commonly expressed in the following … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Peirce’s Law

Posted on October 18, 2023 by Jon Awbrey

A Curious Truth of Classical Logic Peirce’s law is a propositional calculus formula which states a non‑obvious truth of classical logic and affords a novel way of defining classical propositional calculus. Introduction Peirce’s law is commonly expressed in the following … Continue reading →

Posted in C.S. Peirce, Equational Inference, Laws of Form, Logic, Logical Graphs, Mathematics, Peirce, Peirce's Law, Proof Theory, Propositional Calculus, Propositions As Types Analogy, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , | 9 Comments

Survey of Animated Logical Graphs • 6

Posted on October 16, 2023 by Jon Awbrey

This is a Survey of blog and wiki posts on Logical Graphs, encompassing several families of graph-theoretic structures originally developed by Charles S. Peirce as graphical formal languages or visual styles of syntax amenable to interpretation for logical applications. Beginnings Logical Graphs … Continue reading →

Posted in Amphecks, Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Computational Complexity, Constraint Satisfaction Problems, Differential Logic, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Minimal Negation Operators, Model Theory, Painted Cacti, Peirce, Proof Theory, Propositional Calculus, Propositional Equation Reasoning Systems, Spencer Brown, Theorem Proving, Visualization | Tagged , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment

Praeclarum Theorema • 3

Posted on October 15, 2023 by Jon Awbrey

Re: Praeclarum Theorema • (1) • (2) The steps of the proof are replayed in the following animation. Reference Leibniz, Gottfried W. (1679–1686?), “Addenda to the Specimen of the Universal Calculus”, pp. 40–46 in G.H.R. Parkinson (ed., trans., 1966), Leibniz … Continue reading →

Posted in Animata, C.S. Peirce, Cactus Graphs, Deduction, Equational Inference, Form, Laws of Form, Leibniz, Logic, Logical Graphs, Mathematics, Model Theory, Painted Cacti, Praeclarum Theorema, Proof Theory, Propositional Calculus, Propositional Equation Reasoning Systems, Relation Theory, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , , | 6 Comments