"Conscience" and "conscientious" both come from the Latin verb conscire, a word that means "to be conscious" or "to be conscious of guilt" and that traces back to a still older Latin word, scire, meaning "to know."

What is the source of consciousness?

All consciousness arises from the brainstem, and it starts as feelings. While people with damaged or even missing cerebral cortices display many signs of consciousness, even a small amount of damage to a part of the brainstem called the reticular activating system reliably obliterates consciousness.

Where does conscience come from in the brain?

Since at least the nineteenth century, scientists have known that the cerebral cortex is important for consciousness. Fresh evidence has highlighted a posterior-cortical 'hot zone' that is responsible for sensory experiences.