Anumana: right knowledge obtained by a process of inference. First, by observation we find that wherever there is smoke there is fire. Then, when in a certain place we see smoke, we infer that fire exists in that place. The knowledge of the existence of fire has here been obtained by a process of inference.

Sabda: right knowledge obtained through a verbal statement proceeding from a trustworthy source.

Upamana: right knowledge of similarity obtained by a process of comparison. To explain: A man learns for the first time from a forester that a gayal (a wild animal) is like a cow. Afterwards, on seeing an animal like a cow in a forest, the perception of similarity reminds him of the forester' directions, and he concludes that it is gayal.

Arthapatti: right knowledge in the form of presumption: surmising a thing to account for something else known. Thus, in the case of a fat man who does not eat by day, his fatness cannot be explained except through the surmisal of his eating at night. By presumption, we come to know that he eats at night.

Abhava: an immediate consciousness of the non-existence of something by the non-perception

thereof where, if it existed, it ought to have been perceived. When, for instance, in a lighted room we do not perceive a jar, we become immediately conscious that the jar does not exist there.

Sambhava: the right knowledge we have as to the existence of a part when we know that the whole of which it is the part exists. If we know that a man has one hundred rupees, it is a right knowledge to know that he has ten rupees.

Aitihya: right knowledge obtained by tradition, which is transmitted from generation to generation, and of which the source is unknown; such is the knowledge concerning a Yaksha (an invisible being) said to occupy a tree.

These terms, pratyaksha, etc., are applied to prama or the right knowledge thus obtained, as well as to pramana, the karana or the means by which such a knowledge is obtained. While the Charvakas dogmatically discard as unreliable all sources of information other than sensuous perception, others reduce some of the eight sources of knowledge mentioned above, to one or another of those which they recognize as independent sources of knowledge.

The Vaiseshika's Categories.

20. The followers of Kanada mention six padarthas or categories of existence; viz.:

I. Dravya, substance. II. Guna, quality. III. Karma, motion or activity. IV. Samanya, genus. V. Visesha, difference. VI. Samavaya, intimate relation or co-inherence.

21-23. I. Substances are nine:

Bhutas or elements (1. earth, 2. water, 3. light, 4. air and 5. ether.) 6. Dis, space. 7. Kala, time. 8. Atman, soul. 9. Manas, mind.

II. Qualities are twenty-four: