Siva is spoken of as being in eight forms (Ashtamurti). The eight forms of Siva are the five elements, the sun, the moon and the priest who performs sacrifice.
Vishnu appeared in the Mohini form after the churning of the milk-ocean. Siva embraced Vishnu in that form. Sasta is the offspring of Siva and Mohini. Sasta is called also by the name Hari-Hara-Putra or the son of Hari and Hara.
Appar wanted all Saivas to regard Vishnu as only another aspect of Siva.
According to Appar, there are three aspects of Siva. (1) The lower Siva who dissolves the world and who liberates Jivas from their bondage. (2) The higher form is called Parapara. In this form Siva appears as Siva and Sakti (Ardhanarisvara). It has the name Param-Jyoti.
Brahma and Vishnu were not able to comprehend this Jyoti. (3) Beyond these two forms is the Param, or the ultimate being from whom Brahma, Vishnu, Rudra originate. It is purely the Saiva form. It is formless. It is the Sivam of the Saiva Siddhanta. It is Para Brahman of the Upanishads and Vedantins.
The Mahavishnu of Vishnu Purana corresponds to Param of Saiva Siddhantins. Narayana or the higher Vishnu corresponds to the Param-jyoti of Appar or Saiva Siddhantins. The lower Vishnu does the function of preservation. He corresponds to the lower Siva.
What is the inner meaning of all the Saiva allusions about Vishnu worshipping Siva and all the Vaishnava allusions about Siva worshipping Vishnu? The lower Siva must take Narayana, the Parapara or Param-jyoti as his Superior. The lower Vishnu must take Param-jyoti or the Parapara as his Superior. The higher Vishnu and higher Siva are identical. They are inferior to Param, the Highest.
In that highest condition called Siva Mukti, there is no duality. No one can see anything. One merges himself in Sivam or the Highest. If you wish to see, you will have to come to the stage immediately below the Highest.
The Siva Murti or manifestation is inferior to the real ‘Sivam’ which is formless.
According to the Saiva Siddhanta philosophy, the Tattvas are reckoned as ninety-six. They are as follows:
24 Atma Tattvas, 10 Nadis, 5 Avasthas or conditions, 3 Malas or impurities, 3 Gunas (Sattva, Rajas and Tamas), 3 Mandalas (Surya or the sun, Agni or the fire and Chandra or the moon), 3 humours (Vata, Pitta and Sleshma), 8 Vikaras or modifications (Kama, Krodha, Lobha, Moha, Mada, Matsarya, Dambha and Asuya), 6 Adharas, 7 Dhatus, 10 Vayus, 5 Koshas and 9 doorways. The twenty-four Tattvas are the 5 elements (Bhutas), 5 Tanmatras (Sabda, etc.), 5 Jnana-Indriyas, 5 Karma-Indriyas and 4 Karanas (Manas, Buddhi, Chitta and Ahamkara). All these 96 relate to the body. Over and above these 96, there are the 5 Kanchukas or coverings. They are Niyati, Kaala, Kala, Raga and Vidya. The five enter the body and cause weariness to the Tattvas of the body and afflict the body.
The Suddha Saiva does not attain the final emancipation by Kriya (Kiriyai) alone. He attains only Salokya. Jnana in Kriya leads to Salokya, the world of Siva. Jnana in Charya (Chariyai) leads him to Samipya (proximity to Siva). Jnana in Yoga bestows on him Sarupya (likeness in form). Jnana in Jnana leads him to Sayujya, merging or absorption.
‘Ambalam’ means ‘open space of the heart’ or Chidakasa or Chidambaram.
And Lingam is the Visvarupa or the God’s form of the Universe.
He who brings about the destruction of the world is Siva or Rudra. That is the reason why He is held superior to Brahma and Vishnu.
The Siddhantins divide Jivas or Pasus into three orders, viz., Vijnana Kalar, Pralaya Kalar and Sakalar. Vijnana Kalar have only the Anava Mala (egoism). Pralaya Kalar have Anava and Maya. Sakalar have all the Malas, Anava, Karma and Maya. The Malas affect only the Jivas and not Siva. Those who are freed from the Malas or impurities become identical with Siva. They are Siddhas or perfected beings.