 Thus, according to the Peircean semantics, a formula of the form \(F\varphi\) is true at an instant \(t\) iff every history passing through \(t\) contains some later instant \(t'\) at which \(\varphi\) is true. The strong future operator \(G\) essentially retains its original semantics but now reads “it will necessarily always be the case that \(\dots\)”. Note that in this case the universal quantification over histories is redundant and can be omitted without loss of meaning. The dual of \(G\) is the weak future operator of TL, which is now denoted by \(f\), while the dual of the Peircean \(F\) is commonly written \(g\) (cf. Burgess 1980). All future operators involve (implicitly or explicitly) quantification over histories and are modalized: they capture possibility and necessity regarding the future. There is no actual future and, accordingly, no notion of plain future truth. As this accords well with the view held by Peirce, Prior called this system ‘Peircean’.