One of the many Tibetan contributions to the Buddhist 'apoha' theories, also called 'differentiation theories of meaning', is offered here in the form of an annotated edition of the fourth chapter of Sa-skya Pan.dita's Tshad-ma rigs-pa 'i gter, which is so far the earliest indigenous Tibetan text on Buddhist logic and epistemology. The edition of this chapter is based on the framework provided by the author's auto-commentary, the Tshad-ma rigs-pa'igter-gyi rang-'grel.