My understanding is that consciousness arises from contact between a sensory organ and its sense object. There are therefore six kinds of consciousness:
‘The six classes of consciousness should be understood.’ That’s what I said, but why did I say it? Eye consciousness arises dependent on the eye and sights. Ear consciousness arises dependent on the ear and sounds. Nose consciousness arises dependent on the nose and smells. Tongue consciousness arises dependent on the tongue and tastes. Body consciousness arises dependent on the body and touches. Mind consciousness arises dependent on the mind and thoughts. ‘The six classes of consciousness should be understood.’ That’s what I said, and this is why I said it.
“Mind-consciousness” is what a lot of us think of as simple awareness. But this kind of consciousness depends on contact with mental objects, and it is possible to be aware without contact with mental objects.
From AN 9.36…
They contemplate the phenomena there—included in feeling, perception, choices, and consciousness—as impermanent, as suffering, as diseased, as a boil, as a dart, as misery, as an affliction, as alien, as falling apart, as empty, as not-self. They turn their mind away from those things, and apply it to the deathless: ‘This is peaceful; this is sublime—that is, the stilling of all activities, the letting go of all attachments, the ending of craving, fading away, cessation, extinguishment.’
Again, if the consciousness aggregate were simple awareness, we would never know if we had reached Nibbana since that aggregate is inconsistent. We could become aware of Nibbana, sure, but then our consciousness would change or fall away and we could never say that Nibbana was stable or deathless. How could we confirm that?
Furthermore, consider AN 10.81…
“Bāhuna, the Realized One has escaped from ten things, so that he lives unattached, liberated, his mind free of limits. What ten? Form … feeling … perception … choices … consciousness … rebirth … old age … death … suffering … defilements … Suppose there was a blue water lily, or a pink or white lotus. Though it sprouted and grew in the water, it would rise up above the water and stand with no water clinging to it. In the same way, the Realized One has escaped from ten things, so that he lives unattached, liberated, his mind free of limits.”
How can one be free from consciousness AND know that they are free from it?