Aithihyam in Hinduism is the tradition or long standing popular belief. Systems of Hindu philosophy invariably speak of epistemology, the means which result in valid knowledge. The school of Hindu logic, Nyaya speaks of the four major means of knowledge – perception, inference, analogy, verbal testimony. Other schools add some other means as well such as alaukika pratyaksha, extraordinary perception and abhava, non-presence and others.
Vedas are acclaimed by all the astika schools as sabda pramana or verbal testimony. The words of a trustworthy person are also considered authentic. Aithihyam or popular belief is included under verbal testimony. An illustration of aithihyam is a belief for instance, that ‘Yaksha, a super-human spirit lives in this banyan tree.” Such statements are taken as authoritative and its veracity is not verified.
In the medical schools of Charaka also, aithihyam is regarded as a testimony. For, it is believed that the person, now not known, who originally made this statement ought to have uttered only the truth. Aithihyam is thus given credibility by the Hindu psyche. Apart from the common beliefs at the popular Hindu level, there are also some local traditions in the realms of religious practices that are also called aithihyam. While many observances of religious vows are based on local traditions, the absence of verification, sometimes, exposes them to fall into the pit of superstitions. Aithihyam, ultimately, is that where practices supersede scriptural sanctity.