Shabda is valid source, of knowledge in all the systems of Indian Philosophy. Also in the Nyaya system, the fourth kind of valid knowledge is shabda.
It is defined, as the statement of a trustworthy person (aptavakya) and consists in understanding its meaning.
Testimony is always personal. It is based on the words of a trustworthy person, human or divine. Testimony is of two kinds-
- Vaidika, and
- secular (laukika).
Vaidika: The Vaidika testimony is perfect and infallible because the Vedas are spoken by God;
secular (laukika): secular testimony, being the words of human beings who are liable to error, is not infallible. Only the words of trustworthy persons who always speak the truth are valid; others are not.
A word is a potent symbol which signifies an object and sentence is a collection of words. But a sentence in order to be intelligible must conform to certain conditions.
These conditions are four-
- Akanksha,
- Yogyata,
- Sannidhi and
- Tatparya.