Pramaana is that which establishes the truth or rightness of a thing (or belief). We have fourteen basic sastras (Science) that pertain to dharma, that is canonical texts that deal with what has come to be known as Hinduism and what has been handed down to us from the time of the primordial Vedas. These treatises tell us about the doctrines and practices of dharma.
The Vedas -- Rigveda, Yajurveda, Samaveda and Atharvanaveda -- are the first four of the pramaanas (authoritative texts) of our religion which is directly originated from Iswara (God).Of the remaining ten, six are Angas of the Vedas and four are Upangas which are all man made.
Man possesses a number of angas or limbs. In the same way the Vedas personified -- the Vedapurusa -- has six limbs.The four Upangas, though not integral to the Vedas, are supporting limbs of the Vedapurusa. The Angas, as already stated, are six in number -- Siksa, Vyakarana, Chandas, Nirukta, Jyotisa and Kalpa. The four Upangas are Mimamsa, Nyaya, Purana and Dharmasastra.
The Vedas must be learned only along with the Angas and Upangas. Such a thourough study of the scripture is called "Sa-Anga-Upanga-adhyayana" (study of the Vedas with the Angas and Upangas). The term "sangopanga", which has come into popular usage, is derived from this. If a speaker deals with a subject thoroughly, whether it be politics or something else, we use the word "sangopanga" in describing his performance. The term refers to the ancient caturdasa-vidya (the six Angas plus the four upangas). This six Veda Angans forms the basic qualification to get educated about the Vedas. Only then one can grasp the true and indepth meanings of Vedas, without which it is like trying to do Doctorate in Mathematics without even knowing what is addition, subtraction, division or multiplication.
The Vedas form the core of our religion and are the direct authority for our dharma and for all our religious practices. "Pramanam Vedasca- Vedas are the Pramana”, says the Apastamba Dharmasutra. The Vedas are indeed the sources of all dharmas as well as the authority on which they are founded. Throughout India, Manu's Dharmasastra is held in the highest esteem. But does it claim that it is the authority for all dharma? No. "Vedo'khilo dharmamulam", says Manu, i. e. the Vedas constitute the root of all dharma. They prescribe the dharma for all time, he says. All other scriptures of Hinduism including Ayurveda, Dhanurveda, Arthasasthra and Gandharvaveda are called Upavedas, subsidiary Vedas. Their connection with the prime scripture is thus obvious.
"Vid" means "to know". From it is derived "vidya" which means a work that imparts knowledge, that sheds light on the truths of religion. That there are fourteen treatises on vidya is mentioned in the below two stanzas: "vidya hyetascaturdasa" and "vidyanam dharmasya ca caturdasa". The fourteen are not only sastras that impart knowledge but also treatises on normal principles. That is why they are called "vidyasthanas" and "dharmasthanas". Though "vid" means to know, the word does not connote every type of knowledge. The "vid" in "vidya" means knowledge of truth. The English words "wit" and "wisdom" are derived from this root. And it is from the same root that we have "Veda", which term may be said to mean literally the "Book of Knowledge". As sources of knowledge the fourteen sastras are called "vidyasthanas", that is they are "abodes of knowledge or learning". The dharmasthanas ("abodes of dharma") are also the abodes of vidya.