So like, imagination? Does that count? I mean even in dreams we see, hear, feel, etc. I still can't grasp what a "non-physical sense" is.
It would be easy. There would be a consensus and you'd be able to show people you could smell things.
Put two identical paper bags in front of someone, fill one with flowers and one with rotting fish. Show the 99% that you can consistently pick out the one with the rotting fish. They might be amazed at first, but you could do it every time. You could do it easily, without a second thought, in double-blind studies, and you'd never miss even once. You could wiggle your nose while you do it, and explain to the 99% that by breathing in through your nose you can detect the differences in things based on microscopic bits of them that drift into the air.
Easy. No one can do that with ghosts, other realms or any of that. So how can we tell "real" other-worldly detection from the large percentage of charlatans that are sure to exist?