Senses are inputs for the brain. Proprioception, nociception, and the other internal senses are the "outside world" as far as the brain is concerned.
They regard the outside world, but they cannot be corroborated, which seems important to your idea of "senses." I say this is important based on when you say, "As for schizophrenia, the beliefs and feelings that they have can't be corroborated with enough people."
Also, they are controlled completely internally. Nocioception is a signal from the nerves inside the body to the brain. It doesn't require any outside stimulus whatsoever. Proprioception even more so (although it is cross-referenced with vision in most humans, making it somewhat reliant on vision). Sense of oneness (faith in something greater) also is internally controlled but regards the outside world.
It is literally the thing in your brain that keeps you from feeling as though you are the only human alive. The left side of your brain has sense of self, the idea that you are a unique entity, and the right side has sense of faith, that you are part of something greater than yourself.
As you pointed out, hallucinations of a schizophrenic cannot be corroborated. Sense of faith can
be corroborated. Why are we accepting "vision" as a sense into the discussion but not faith?
Our intrinsic notion of truth is developed by our senses. We believe what we see because it confirms what we have seen. This is also the reason we don't accept changes such as alien invasions and zombie brainfests.
Yes, that is another way of saying what I said. Faith in something greater is perceived as a truth because it is developed by the sense of faith in such. The difference between zombies and God is that the concept of a God is not contrary to any of the other information we get from any of our other senses, whereas the concept of zombies is.
As I said, there is specific neurological evidence that faith in a large portion of the human population has a physiological cause and is not simply an intellectual exercise of weighing options that atheists like you or I would be inclined to expect. People choose what specific God or community to have "faith" in, but denying faith itself would be like denying what you see despite it being reaffirmed by the majority of those around you
Emotions originate in deeper parts of the brain and are different physiologically than the sense of faith. They don't lead us to believe in a specific idea of truth; they are reactions to such belief. They are empirically different than the sense of faith, which:
a) originates primarily in a section of the brain which deals with higher functions and senses
b) behaves physiologically like a sense
c) leads people to a corroborative sense of truth (and leads all people with it to the same conclusion--that there is something greater than ourselves)
d) can be reaffirmed by the other senses
a) originate primarily in the lower levels of the brain
b) behave physiologically different than senses
c) do not lead people to universal conclusions, but simply react to the conclusions which are made
d) can not be reaffirmed