The paper introduces precise definitions of the inevitabilist and contingentist positions. On this basis, it reveals the analytical structure and some inherent difficulties of the contingentist/inevitabilist issue. It then discusses some of these difficulties, relying on the thought-experiment of a ‘divided physics’. Along the way, it investigates the kinds of differences that two alternative physics should present, if they are to give rise to non-benign forms of contingentism.Keywords: Contingency; Inevitabilism; Incommensurability; Theory-comparison; Scientific realism; Constructivism.