That would depend on what your definition is of spirit or spirits is. Many accept anything abby-normal as good or an experience in the unseen world as good or from God.
A non-physical entity that possesses a will... that’s probably a pretty good working definition. I’m not making any value judgment upon experiences with spirits. One could have an experience with Old Scratch and that would be evidence of spirit, but also perhaps not a very helpful one except as much as it may drive someone to seek God.
We can always fall back on reading tea leaves - or entrails...