In the first book, consisting of two daily lessons, he describes all the categories which are capable of intimate relation. In the first _áhnika_ he defines those which possess "genus" (_játi_), in the second "genus" (or "generality") itself and "particularity." In the similarly divided second book he discusses "substance," giving in the first _áhnika_ the characteristics of the five elements, and in the second he establishes the existence of space and time. In the third book he defines the soul and the internal sense, the former in the first _áhnika_, the latter in the second. In the fourth book he discusses the body and its adjuncts, the latter in the first _áhnika_, and the former in the second. In the fifth book he investigates action; in the first _áhnika_ he considers action as connected with the body, in the second as belonging to the mind. In the sixth book he examines merit and demerit as revealed in Śruti; in the first _áhnika_ he discusses the merit of giving, receiving gifts, &c., in the second the duties of the four periods of religious life. In the seventh book he discusses quality and intimate relation; in the first _áhnika_ he considers the qualities independent of thought, in the second those qualities which are related to it, and also intimate relation. In the eighth book he examines "indeterminate" and "determinate" perception, and means of proof. In the ninth book he discusses the characteristics of intellect. In the tenth book he establishes the different kinds of inference.[156] The method of this system is said to be threefold, "enunciation," "definition," and "investigation."[157] "But," it may be objected, "ought we not to include 'division,' and so make the method fourfold, not threefold?" We demur to this, because "division" is really included in a particular kind of enunciation. Thus when we declare that substance, quality, action, generality, particularity, and intimate relation are the only six positive categories,--this is an example of enunciation. If you ask "What is the reason for this definite order of the categories?" we answer as follows:--Since "substance" is the chief, as being the substratum of all the categories, we enounce this first; next "quality," since it resides in its generic character in all substances [though different substances have different qualities]; then "action," as it agrees with "substance" and "quality" in possessing "generality;"[158] then "generality," as residing in these three; then "particularity," inasmuch as it possesses "intimate relation;"[159] lastly, "intimate relation" itself; such is the principle of arrangement.