Category Archives: Peirce

Peirce’s Law • 1

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

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

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

Logical Graphs • Formal Development 8

Exemplary Proofs Using no more than the axioms and theorems recorded so far, it is possible to prove a multitude of much more complex theorems.  A couple of all‑time favorites are linked below. Peirce’s Law Praeclarum Theorema cc: FB | … Continue reading

Posted in Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Deduction, Diagrammatic Reasoning, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Painted Cacti, Peirce, Propositional Calculus, Propositional Equation Reasoning Systems, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , | 3 Comments

Logical Graphs • Formal Development 7

Frequently Used Theorems (concl.) C3.  Dominant Form Theorem The third of the frequently used theorems of service to this survey is one Spencer Brown annotates as Consequence 3 (C3) or Integration.  A better mnemonic might be dominance and recession theorem (DART), but … Continue reading

Posted in Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Deduction, Diagrammatic Reasoning, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Painted Cacti, Peirce, Propositional Calculus, Propositional Equation Reasoning Systems, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , | 3 Comments

Logical Graphs • Formal Development 6

Frequently Used Theorems (cont.) C2.  Generation Theorem One theorem of frequent use goes under the nickname of the weed and seed theorem (WAST).  The proof is just an exercise in mathematical induction, once a suitable basis is laid down, and … Continue reading

Posted in Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Deduction, Diagrammatic Reasoning, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Painted Cacti, Peirce, Propositional Calculus, Propositional Equation Reasoning Systems, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , | 3 Comments

Logical Graphs • Formal Development 5

Frequently Used Theorems To familiarize ourselves with equational proofs in logical graphs let’s run though the proofs of a few basic theorems in the primary algebra. C1.  Double Negation Theorem The first theorem goes under the names of Consequence 1 … Continue reading

Posted in Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Deduction, Diagrammatic Reasoning, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Painted Cacti, Peirce, Propositional Calculus, Propositional Equation Reasoning Systems, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , | 3 Comments

Logical Graphs • Formal Development 4

Equational Inference All the initials have the form of equations.  This means the inference steps they license are reversible.  The proof annotation scheme employed below makes use of double bars to mark this fact, though it will often be left … Continue reading

Posted in Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Deduction, Diagrammatic Reasoning, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Painted Cacti, Peirce, Propositional Calculus, Propositional Equation Reasoning Systems, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , | 3 Comments

Logical Graphs • Formal Development 3

Logical Interpretation One way of assigning logical meaning to the initial equations is known as the entitative interpretation (En).  Under En, the axioms read as follows. Another way of assigning logical meaning to the initial equations is known as the existential interpretation … Continue reading

Posted in Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Deduction, Diagrammatic Reasoning, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Painted Cacti, Peirce, Propositional Calculus, Propositional Equation Reasoning Systems, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , | 3 Comments

Logical Graphs • Formal Development 2

Axioms The formal system of logical graphs is defined by a foursome of formal equations, called initials when regarded purely formally, in abstraction from potential interpretations, and called axioms when interpreted as logical equivalences.  There are two arithmetic initials and … Continue reading

Posted in Animata, Boolean Algebra, Boolean Functions, C.S. Peirce, Cactus Graphs, Deduction, Diagrammatic Reasoning, Equational Inference, Graph Theory, Laws of Form, Logic, Logical Graphs, Mathematics, Painted Cacti, Peirce, Propositional Calculus, Propositional Equation Reasoning Systems, Semiotics, Spencer Brown, Visualization | Tagged , , , , , , , , , , , , , , , , , , , | 3 Comments