Category Archives: Peirce

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 →

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 →

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 →

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 →

Logical graphs are next presented as a formal system by going back to the initial elements and developing their consequences in a systematic manner. Continue reading →

A logical graph is a graph-theoretic structure in one of the styles of graphical syntax that Charles Sanders Peirce developed for logic. Continue reading →