I said active proof, not absolute proof.
The "fact" that thus far there is considerable physical evidence that human consciousness is a result of the chemical reactions in the brain and thus far there is no evidence that human conscious is anything other than a result of the chemical reactions in the human brain.
What physical evidence exists that proves human consciousness is the result of the chemical reactions in the brain? I know of no evidence that proves a causal relationship between chemical reactions and consciousness - a loose correlation but not causal.