Abstract

This paper investigates two forms of the Routley star operation, one in Routley & Routley 1972 and the other in Leitgeb 2019. We use the background of object theory to define both forms of the Routley star operation and show how the basic principles governing both forms become derivable and need not be stipulated. Since no mathematics is assumed by our background formalism, the existence of the Routley star image s* of a situation s is therefore guaranteed not by set theory but by a theory of abstract objects. The work in the paper integrates Routley star into a more general theory of (partial) situations that has previously been used to develop the theory of possible worlds and impossible worlds.