Srutis and Smritis

It is said the ancient Hindus divided their literature into two classes:
(i) Sruti – what they had heard with their ears,” or Revelation. These are the Vedas
(2) Smriti – what their fathers transmitted to them,” or Tradition. These are other texts, based on the authority of the Vedas.

Smriti comprehends all post-Vedic literature under four heads :
1. The six Vedangas, viz. : (1) Siksha, the science of pronunciation; (2) Chandas, metre; (3) Vyakarana, grammar; (4) Nirukta, explanation of Vedic words ; (5) Jyotisha, astronomy ; and (6) Kalpa, ceremonial, including Srauta-Sutras, rules for applying the Mantras and Brahmanas to Vedic sacrifices; Grya-Sutras, rules relating to domestic rights ; Samaya Charika-Sutras, rules relating to conventional usages: the last two are called Smarta-Sutras.
2. The Darsanas, systems of philosophy.
3. The Dharma-Sutras, law books such as Manu, Yajnavalkva, and others, which are supposed to have grown out of the Smarta-Sutras.
4. The Itihasas, viz. : the two epic poems, the Mahabarata and Ramayana; the eighteen Puranas, or ancient legendary lore ; and the Tantras.

NOTE: According to Patanjali’s Yoga Sutras, smriti is one of the five vritti, which are the thoughts or fluctuations of the mind that affects one’s consciousness. The other four vritti are pramana, viparyaya, vikalpa and nidra.