Generally speaking, the Vaiśeṣika theory of numbers supplies us with many interesting problems which underlie the relation between subject and object. No philosophical schools in ancient India, except for the Vaiśeṣika School and the Nyāya School, dealt systematically with this theory. The Vaiśeṣika School is characterized by conceptual realism and pluralism, and espouses the system of six (or seven) padārtha-s (substance, quality, etc.). Saṃkhyā is one of the twenty-four qualities, and the cause of the concepts of numbers (e. g., one, two). Therefore, saṃkhyā should be regarded as the “proto-type of numbers” or “number-ness” rather than be called “number.” So proto-types of individual numbers, dvitva, etc., should be called the proto-type of the number two, “two-ness” or duality, etc.The Vaiśeṣika School gives a very complicated and difficult explanation of this theory of saṃkhyā (Praśastapāda-bhāṣya: saṃkhyā-prakaraṇa). The complicated nature and difficulty of this explanation is caused mainly by two reasons: The first is that the proto-type of the number two, etc., which causes the concept of the plural number, is not directly inherent in things, but occurs only after the selection of things by subject (perception itself). According to the Vaiśeṣika School, dvitva, etc., occurs from the motive of apekṣā-buddhi (perception as a motive). The second reason is that the perception of numbers is thought to belong to conceptual perception (savikalpaka-pratyakṣa), or the perception of the relation between what is to be qualified (viśeṣya) and the qualifier (viśeṣaṇa). It must be noted that the perception of numbers is discussed with deliberation and in detail, when compared with all the individual cases of conceptual perception. Therefore, the criticism of the theory of the proto-type of numbers (saṃkhyā) turns out to be that of the Vaiśeṣika theory of perception. The main opponent who bitterly criticized this theory was the Yogācāra School of Buddhism. The author will investigate this criticism in a future article.
