1. From the first angle we can still distinguish a few different perspectives: From the so-called ‘traditionalist ’ approach of one of the most prolific and foundational figures, Ananda Coomaraswamy, to the comparativist universalistic objectives of specialists in Abhinavagupta like K.C. Pandey (Cf. his 1959Comparative Aesthetics, (II vols.), Chokhamba Sanskrit Series, Varanasi, and also his major work on Abhinavagupta: 1963Abhinavagupta. An Historical and Philosophical Study. Chokhamba, Varanasi), and to other specialized books on rasa theory from the 1960s and 1970s like the two popular works by Masson and Patwarhan: Masson, J.L. & Patwarhan, M.V. 1970, Aesthetic Rapture, (II vols.) Deccan College, Poona; and 1961, Santarasa and Abhinavagupta ’ s Philosophy of Aesthetics,Bhandarkar Oriental Research Institute, Poona, to mention just a few names of Indian origin, to studies by Western scholars mostly published in journals, such as Gerow, E., 1994, ‘Abhinavagupta ’ s Aesthetics as a Speculative Paradigm ’, in: Journal of the American Oriental Society, 114.2, pp. 186–208. Among the second approach, See for example the first essay of the entry ‘Indian Aesthetics ’ by Gitomer, D.L., in Kelly, M. (ed.), Encyclopedia of Aesthetics, 1998, Oxford University Press, Oxford, vol. II, pp. 482–490. This encyclopaedia, a recent and ambitious project, begins with an entry on Abhinavagupta and covers main topics of non-Western aesthetics
2. There are numerous recent studies on this philosophy. See, for example, Mishra, K., 1999, Kashmir Saivism. The Central Philosophy of Tantrism, Sri Satguru Publications, Delhi
3. Although references to these states can already be found in ancient upanisads such as the Chandogya, the Mandukya Upanisad is entirely devoted to describe these four states relating them with the mystic syllable ‘aum ’ . See, for example, its English translation in: Radhakrishnan, S., [1953] 1996, The Principal Upanisads, HarperCollins Publishers, New Delhi, pp.695–705
4. See Aitareya Upanisad 1.2.4., where it is described how, at the request of the cosmic elements, the soul of the universe (ātman) determines their settlement in the different organs of the human body: fire, transformed into speech, enters the mouth, wind, transformed into sight, enters the eyes, space enters the ears, plants and trees, transformed in hairs, enter the skin, the moon, transformed into mind, enters the heart, death, transformed into expiring air, enters the navel and water, transformed into semen, enters the male sexual organ
5. Tripathi, K.D., 1995, ‘From Sensuous to Supersensuous: Some Terms of Indian Aesthetics ’, in: Vatsyayan, K. (ed.), Prakrti. The Integral Vision, vol. 3. The Agamic Tradition and the Arts (ed. Bäumer, B.), Indira Gandhi National Centre for the Arts and Motila Banarsidass, New Delhi, p. 75