The smell of coffee is not the molecules in the air; the molecules in the air cause you to smell something, but the smelling itself is a subjective experience. The same for the signals in our brain; that's an objective explanation of the cause of our experience, but the subjective experience in itself doesn't seem to be able to be broken down into other things. It's prior to all other things we can know.
That's a fair argument. Subjective experience doesn't require knowledge of how anything works- you can experience the stimuli without any understanding
