The following is an English summary of my Japanese article, Kataoka 2016d. (See my work list)
Dignāga's Semantics by Non-exclusion and Inclusion
Dignāga claims that the semantic theory of “something having a universal” (jātimat) cannot explain co-referential expressions such as “existent pot” (san ghaṭaḥ), because in this theory the word “existent” does not include (vyāpti) or imply (ākṣepa) a pot. Dignāga's own theory of “something having exclusion” (apohavat), on the other hand, can explain it, because given his presuppositions the word “existent” does include and imply a pot. The former theory presupposes “strong” connections between words and meanings. Only something existent (sat) is positively (anvayadvāreṇa) connected with the word “existent.” Therefore, a pot is not connected with the word “existent.” The latter theory, on the other hand, presupposes “weak” connections learned through co-absence (vyatireka): The word “existent” has never been seen applied to something which is not existent. The meaning of “existent” is whatever remains after excluding non-existent things. In this negative learning a pot is not excluded (anapohana, apratikṣepa). Therefore, the co-referential expression “existent pot” (or “a pot is existent”) is justified. This is also due to the characteristic feature of exclusion (apoha) which is precisely non-existent (abhāva) and a non-entity (adravya). Exclusion does not intervene (vyavadhāna) between words and their meanings. The word “existent” can directly mean (sākṣādvṛtti) something existent without exclusion intervening. Thus, the theory of apohavat has no fault of dependency (pāratantrya) which jātimat theory has. In the latter theory a real universal such as existence (sattā) intervenes between the word “existent” and its meaning, i.e., something existent.