CatGloss

T .Itisworthpausingheretoreflectonwhathasbeenaccomplished.Wenowknowthatthetrutharrowsin . It is worth pausing here to reflect on what has been accomplished. We now know that the truth arrows in mathbf{Set}^{p} arepreciselythosenaturaltransformationswhosecomponentsinterpretthecorrespondingconnectivesontheHeytingalgebrasin are precisely those natural transformations whose components interpret the corresponding connectives on the Heyting algebras in mathbf{P} .ButrememberthatthetrutharrowsweredefinedlongbeforeintuitionisticlogicandHAswerementioned.Theyarosefromacategorialdescriptionoftheclassicaltruthfunctionsin . But remember that the truth arrows were defined long before intuitionistic logic and HA’s were mentioned. They arose from a categorial description of the classical truth functions in mathbf{Set} $ . Subsequently