 Even though the connection was not pursued further in their paper, one cannot help realizing that their modality interpretation is boosted by a relation to MacColl’s implication since C. I. Lewis’ strict implication is a beginning of modal logic. However, equating Peirce’s triadic logic with modal logic, the modality view needs to explain the relation between Peirce’s Gamma graph lecture in 1903c (which is about modality) and the triadic logic notes written in 1909 ([Ms 339] 340v, 341v, 344r).  Modal logic explored in Gamma graphs is the extension of classical logic, which required new vocabulary, e.g., broken cuts and tincture. Modal logic does not have to be non-standard. On the other hand, triadic logic does not add any vocabulary, but brings in different interpretations, and becomes non-standard logic. On a slightly different note, Fisch and Turquette’s suggests Peirce’s tychism (the view that indeterminacy is part of the reality) as a motivation for Peirce’s invention of triadic logic. If so, Peirce’s triadic logic is a reflection of his own metaphysics.