My teacher, Swamini Atmaprakasananda, raised a question: If, as in the Gita, Krishna says, ‘I am consciousness’, who is speaking? Consciousness does not speak, nor does the mithyA body-mind-sense complex, all of which are inert matter.
Then, by way of answering her own question, spoke of the levels of knowledge:
Knowledge is of two types: pure knowledge and manifest knowledge. Pure knowledge, śuddha jñānam, is knowledge that is not manifest and vyakta jñānam is knowledge that is manifest. Vedanta says that Reality, the Absolute Truth of this entire cosmos, the one substance of this substantive universe is pure knowledge. (Pure knowledge, pure consciousness, pure awareness are all synonyms.)When you say ‘I’, it is a word which, before it emerged as a sound, must have been in the form of a thought. ‘I’, by itself, is manifest knowledge. ‘I am’ is manifest knowledge. ‘This universe is’ is manifest knowledge. When you say that anything ‘is’, that is manifest knowledge. What is known generally by the term ‘knowledge’ is this manifest knowledge: it could be knowledge of physics, or science or arts, of anything. It takes the form of a thought in the mind. Any knowledge in the mind is based on the fundamental knowledge ‘I am’. One cannot say that there is physics knowledge in the mind, but there is no ‘I am’ thought in the mind.
We call the manifest knowledge ‘I am’ and the knowledge ‘this universe is’ vṛtti jñānam (knowledge in the form of a thought). Vṛtti jñānam can be understood better by using the example of illumination.
Illumination of a room at night involves two aspects: electricity and a bulb. Without either of these there cannot be illumination. The bulb needs to shine and only then can it light up the room. The bulb is incapable of shining by itself: it is dependent on the electricity to shine. Equally, without the bulb, electricity cannot provide illumination: electricity is the invisible factor. The bulb is the manifesting medium for electricity: without the bulb, electricity is not available for transaction. Electricity that exists without the bulb is called ‘pure electricity’ merely to distinguish it from the manifest electricity in the bulb. There is actually no pure or impure electricity, but we use the term ‘pure electricity’ from the standpoint of the manifest electricity.
Similarly, a radiator is also a manifesting medium for electricity: the warmth in the room implies two things, the electricity and the radiator. A fan is another manifesting medium, hair dryer is another, cooker another. Manifesting media are many and different, but the electricity is one.
In the same way, the knowledge that we know, manifest knowledge, vṛtti jñānam, involves two things: thought (the manifesting medium) plus consciousness = knowledge, cognition. When thoughts are not there, consciousness is unmanifest, it remains as ‘pure consciousness’. When consciousness is not manifest, it is not available for transaction. If it is not available for transaction we can easily come to the conclusion that there is nothing there. The fact, however, is that consciousness is existent, but is as good as non-existent when it is not available for transaction. Consciousness is the only existence, how can we think of it as non-existent? There is no other reality other than pure consciousness, pure knowledge.