Tantra & The 18 Sciences of the Philosophia Perennis - The Ashta Dasa Saastras
The 18 varieties of Knowledge ( Vidya ) are all the gross manifestations of Tantra.
Everything has been reduced to the biune principles of Consciousness and Force and this Union of Being and Becoming is the Universe.
The 18 Vidyas ( types of Knowledge) are
The Six Auxiliary Sciences - Vedanga Sastras ( Astrophysics, Kalpa, Nirukta, Phonetics, Grammar, Poetics)
The Six Main Sciences - The Four Vedas - ( Rik, Sama, Yajus & Atharva ) -
Poorva Meemamsa This deals with Karma Kanda
Nyaya Shastra Logic
Mythology - The 18 Treatises of Mythology
Ethics - The Science of Character
Ayurveda - The Science of Medicine
Dhanur Veda - Archery
Gandharva Veda Musicology
Artha Sastra Economics
The six auxiliary sciences have been defined as Apara Vidya ( Relative Knowledge ).
The six main sciences as they deal with the Absolute have been defined as Para Vidya ( Absolute Knowledge ).
Absolute Knowledge and Relative Knowledge together constitute the supreme knowledge.
Integral Knowledge is the confluence of Absolute, Relative and Transcendental knowledge ( Sujnana, Vijnana & Prajnana ).
Vijnana - Relative Knowledge -
Knowledge of Relative Being is Physical Science. All scientific knowledge is relative
Sujnana - Absolute Knowledge. Knowledge of the Absolute; knowledge philosophic.
Prajnana - Knowledge or rather the experience of Transcendence. Experiential Knowledge.
Astrophysics ( Jyothish ) consists of three main brances -
Siddhanta ( Astronony ), Samhita ( Philosophy ) & Hora ( Astrology ). All of them belong to Relative
All sciences barring Vedanta ( The Science of the Absolute ) & Yoga ( The Science of Transcendence ) are relative by nature.
Mythology is the adumbration of philosphic verities. Sir Philip Sydney writes in " An Apologia for Poetry " that the great seers and mystics of yore hid Great Secrets in symbolic stories. ( " which of purpose were written darkly, lest by profane wits it might be abused"). Aurobindo in the Secret of the Veda writes that " this Wisdom is unfit & dangerous to the ordinary human mind and liable to perversion & loss of virtue, if revealed to vulgar and unpurified spirits". Hence the Seers hid the Mysteries in symbolic stories like the Iliad and the Odyssey, the Ramayana & the Mahabharata, books which deal with the Inner War in Man !
The Hidden Foe ( Ego) lodged in the human breast
Man must overcome or miss his higher fate
This is the inner war without escape.
Economics, the Science of wealth, is considered as the 18th science. Among the Four Purusharthas ( Wealth, Ethics, Desire, Salvation ), wealth was considered important because without that the body cannot sustain. "Wealth is the fuel of outer life" averrs Artha Sastra, a treatise on economics. Weath is foremost and is the basis of Kama ( Desire ), Dharma ( Ethics ) & Moksha ( Salvation ) !
Tantra does not condemn the three Ws ( Wealth, Wine and Women ) as evil. Man gets fulfillment through the satiation of desires and only after enjoying finite bliss can he aspire for Infinite Bliss ! Karma gets exhausted after the desires for the mundane are fulfilled and man after becoming blase turns within to the Bliss of the Absolute Self !