In Kaśmir Śaivism, the 36 tattvas describe the Absolute, its internal aspects and the creation including living beings, down to the physical reality. The addition of 11 supplemental tattvas compared to the Sāṃkhya allows for a richer, fuller vision of the Absolute. Going from śiva to pṛithvī tattva we find the process of manifestation, the creation of the universe; going the opposite way we find the process of spiritual evolution culminating with the dissolution in Śiva.
Tattvas divide into three groups: Ashuddha, or impure (material, sensorial, the organs of action, the mind and the ego), Shuddhashuddha, or pure-impure (the soul and its limitations) and Shudda, or pure (internal aspects of the Absolute). The impure tattvas are the domain of objectivity and duality, the pure-impure tattvas are the domain of knowledge and the pure tattvas are the domain of transcendental unity and non-differentiation.
Read more about The 36 Tattvas: The Five Mahābhūtas, The Five Tanmātras - Subtle Mediums of The Sensations, The Five Karmendriyas - Organs of Action, Antaḥkaraṇa - The Inner Instrument, Ṣat Kañcukas, Śuddha Tattvas, Differences From Sāṃkhya, See Also