You can take any feeling, but here I will take the feeling of anger as an example. The next sentence is an everyday simple sentence:
He is angry.
You would be more accurate to say: He looks like I do when I'm angry.
You could say I have a sick feeling in my stomach when I am angry. Or, I have a tension headache when I am angry. Or, I shake like a leaf because of the adrenaline when I am angry. Or, I want to hurt him when I am angry.
Did you notice in all those sentences, you never describe anger, but only what it does to your body, and what you will do because of it, but what is anger? Or any feeling? Are they just the manifestation of a certain combination of neurons firing in a certain sequence?
I think that the understanding I currently have of feelings (if I didn't know better) could lead me to things like souls and ghosts and other apparitions.
Does anyone know of any research being done on this subject?