Consciousness exists. This is in disputable. Indeed consciousness is required to even try denying the existence of consciousness.

Consciousness is non-negateable because (again) it takes consciousness to know or to deny, to prove or refute anything.
One's own conscious-beingness is self-evident, requiring no proof. "I know I am" is a priori to knowing who I am (gender, nationality, desires, interests, occupation, activity, all other concepts).

Knowledge exists in consciousness. There is nothing known except by consciousness. Without consciousness, nothing can be explained.
Consciousness can not be explained away. Science can reveal where to find in the brain, various emotions, intentions, memories and other 'objects of consciousness" and activity.
Science can't explain nor negate consciousness-knowingness (separate from the known) without using the very consciousness that is being investigated.

Thus the Vedas call ultimate reality "sat-chit-ananta" or satcitananda.
Sat=existence
Chit=consciousness
Ananta=limitless; or ananda, usually called bliss but better understood as free of all limitations.

Consciousness is not equivalent to 'what is known', the objects of consciousness, nor to the brain nor to that of which we are aware.