If you do not believe in ghosts/spirits, can you still say you believe in God? After all, isn't God a spirit?
You can say you believe in God without believing in ghosts. If you are equating spirits with ghosts, then the same applies.
I have never said I did not believe in spirits. The Bible clearly speaks of God as spirit (the article “a” is not in the original). People have spirits. All I have said was that the spirits of men do not return to earth as ghosts as we usually think of ghosts. If they did we could not see them, since we are in the physical rather than the spiritual realm. Just as we can not see God we wouldn’t be able to see spirits of people if they were to come back to earth.