Literature in Sanskrit can be broadly divided into texts composed in Vedic Sanskrit and the later Classical Sanskrit. Vedic Sanskrit is the language of the extensive liturgical works of the Vedic religion, which aside from the four Vedas, include the Brāhmaṇas and the Sūtras. The Vedic literature that survives is entirely of a religious form, whereas works in Classical Sanskrit exist in a wide variety of fields including epics, lyric, drama, romance, fairytale, fables, grammar, civil and religious law, the science of politics and practical life, the science of love and sex, philosophy, medicine, astronomy, astrology and mathematics, and is largely secular in subject-matter. While Vedic literature is essentially optimistic in spirit, portraying man as strong and powerful capable of finding fulfilment both here and in the afterworld, the later literature is pessimistic, portraying humans as controlled by the forces of fate with worldly pleasures deemed the cause of misery. These fundamental differences in psychology are attributed to the absence of the doctrines of Karma and reincarnation in the Vedic period, notions which are very prevalent in later times. Works Sanskrit has been written in various scripts on a variety of media such as palm leaves, cloth, paper, rock and metal sheets, from ancient times. Lexicon As an Indo-European language, Sanskrit's core lexicon is inherited from Proto-Indo-European. Over time however, the language exhibits a tendency to shed many of these inherited words and borrow others in their place from other sources. In the oldest Vedic literature, there are few such non-Indo-European words, but these progressively grow in volume. The following are some of the old Indo-European words that eventually fade out of use in Sanskrit: {| |- | ápas || work || c.f. Latin opus |- | kravís || raw flesh || c.f. Latin crūdus |- | dáma- || house || c.f. Latin domus |- | dā́nu- || moisture || |- | háras- || heat || |} Dravidian lexical influence The sources of these new loanwords are many, and vary across the different regions of the Indian subcontinent. But of all influences on the lexicon of Sanskrit, the most important is Dravidian. The following is a list of Dravidian entrants into Sanskrit lexicon, although some may have been contested: {| |- | phálam || ripe fruit || Proto-Dravidian *paḷam |- | múkham || mouth || Proto-Dravidian *mukam |- | kajjala- || soot, lampblack || |- | kaṭu- || sharp, pungent