The literature of the Trika school is divided into three stages: (i) Āgama Śāstra, revealed truth as embodied in the sixty-four monistic Śaiva āgamas and the Śiva Sūtras; (ii) Spanda Śāstra, a group of texts dealing with spanda (‘vibration’), principally the Spanda Kārikās; and (iii) Pratyabhijñā śāstra, the philosophical systematization of the earlier material, which advocates a theology of the recognition (pratyabhijñā) of Śiva in all things. Somānanda's Sivadṛṣti first expounded this view, followed by Utpala's Īśvarapratyabhijñā ( Tr. K. A. Subramaniya Aiyar and K. C. Pandey, Bhāskarī ). The most famous Trika exponent was Abhinavagupta who wrote the Tantrāloka.
The absolute (parama Śiva) of which there is nothing higher (anuttara), is regarded as the union of Śiva and Śakti conceived as prakāśa (light) and vimarśa (awareness). Acting from absolute freedom (svātantrya) equated with Śakti, Śiva manifests the cosmos as Śakti in the form of the thirty-six pure and impure tattvas.
There are four ways to liberation (mukti) or recognition (pratyabhijñā) of parama Śiva: (i) aṇu upāya, direct liberation through grace or the descent of śakti (śaktipāta); (ii) śāmbhava upāya, the absorption of the self in divine consciousness by the upsurge of pre-cognitive emotion which shatters thought construction; (iii) śākta upāya, realization through the development of pure thought, such as ‘I am Śiva’; and (iv) āṇava upāya, meditation on the body, mantra, and chosen deity (iṣṭadevatā).
"Kashmir Śaivism." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (October 21, 2018). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/kashmir-saivism
"Kashmir Śaivism." The Concise Oxford Dictionary of World Religions. . Retrieved October 21, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/kashmir-saivism