We describe the understanding of consciousness in the works of the 11^th century Indian Tantric philosopher Abhinavagupta, which strongly resembled the contemporary clinical classification of consciousness into two axes (of Arousal and Awareness).

Neurologists have been using the two-axis model to study disorders of consciousness for several decades. Arousal is the aspect that is present in wakefulness and reduced in sleep. Awareness refers to the “content” of consciousness – this might take visual, auditory, olfactory or other forms.

Intriguingly, Abhinavagupta used similar terminology to describe consciousness in his works, such as the Tantrasara and the Paratrisika Vivarana. His Tantric philosophy held that consciousness was not opposed to matter, and thus contrasted with the Mind-Body dualism common in early modern Europe.

For Abhinavagupta, consciousness was twofold - composed of (a) Prakasha (Light), and (b) Vimarsha (Reflection). Prakasha, the Light of consciousness, is described as the unchanging ground of everything, indivisible and changeless. He compares it to a smooth, polished mirror, in which all phenomena and objects appear as reflections. Vimarsha, or Reflection, is described as the phenomenon by which the Light of consciousness becomes aware of everything in the universe. Vimarsha can be of various objects, events or emotions.

Thus, Prakasha parallels the modern concept of Arousal – without Arousal, there can be no consciousness, as in comatose patients. Vimarsha parallels the concept of Awareness - it cannot exist without Arousal, it can be of various objects or phenomena, and may combine them in various ways. In conditions like the Vegetative State, there can be Arousal with only limited Awareness.