Abhinavagupta, a prominent Kashmiri Shaivite philosopher, propounded the theory of 'spanda' or vibration, which posits that the entire universe is a manifestation of the dynamic interplay of consciousness and energy.

In the Nyaya-Vaisheshika school, 'akasa' refers to space as an eternal, all-pervading, and indivisible substance that serves as the container for all physical objects.

In Advaita Vedanta, the ultimate reality is Brahman, which is both consciousness and existence. Space is considered to be a manifestation of Brahman and is therefore identical with consciousness.

The Mahayana school of Buddhism places great emphasis on the concept of 'sunyata' or emptiness, which refers to the idea that all phenomena are devoid of inherent existence and are interconnected.

'Chidakasa' is a Sanskrit term that refers to the subtle, inner space of consciousness. It is considered to be the abode of the self or Atman and is often associated with the concept of pure awareness.

Gangesha Upadhyaya, a prominent Navya-Nyaya philosopher, developed the theory of 'khyati' or appearance, which explains how objects are perceived by the mind through the interaction of the senses and the intellect.

In Samkhya philosophy, the three gunas or qualities that constitute the material world are sattva (purity, luminosity), rajas (activity, passion), and tamas (inertia, darkness).

The Brihadaranyaka Upanishad contains the famous statement 'neti neti' (not this, not this) in reference to the nature of Brahman, indicating that Brahman is beyond all conceptualization and description.

'Atman' is a Sanskrit term that refers to the individual self or consciousness. It is often translated as 'soul' or 'spirit' and is considered to be the innermost essence of a being.

Vasubandhu, a prominent Buddhist philosopher, propounded the theory of 'vijnana-matra' or 'consciousness-only', which posits that all reality is ultimately reducible to consciousness.

'Samsara' is a Sanskrit term that refers to the cycle of birth, death, and rebirth. It is considered to be a fundamental concept in Indian philosophy and is associated with the idea of karma and the pursuit of liberation or moksha.

The Brihadaranyaka Upanishad contains the famous dialogue between Yajnavalkya and his wife Maitreyi on the nature of reality, where Yajnavalkya expounds on the concept of Brahman as the ultimate reality.

'Vairagya' is a Sanskrit term that refers to the concept of non-attachment or detachment. It is considered to be an important virtue in Indian philosophy, particularly in the context of seeking liberation or moksha.

Prabhakara, a prominent Mimamsa philosopher, developed the theory of 'apoha' or negation, which posits that words and concepts have meaning by virtue of their negation or exclusion of other possibilities.

'Moksha' is a Sanskrit term that refers to the concept of liberation or freedom from the cycle of samsara. It is considered to be the ultimate goal of many Indian philosophical and spiritual traditions.