I know the difference between spiders, flies, goosebumps, mice and drafts; and the feeling of a dog. Scrappy wouldn't have reacted to Sam's 'ghost'- they were BFFs in this world.
Don't worry, science will catch up someday. In the meantime, as I said previously, and echoed above, check out some quantum physics. It makes doggy-ghosts look positively quotidien.
I think that the vast majority of, what I shall call for brevity, 'supernatural' events are fake. Mistakes, hope, grief, fear, greed, dishonesty.
Leaders learned a long time ago to manipulate religious beliefs and superstitions to keep their underlings in order through fear.
Emperor Constantine (and his mum) re-wrote parts of the Christian Bible to get rid of the idea of reincarnation. They thought it would be easier to scare the populace if they (the populace) thought they only had one go at life, and if they were bad they would burn in hell for all eternity.
Landowners who wished to keep peasants off their land would certainly welcome, and probably activity promote, rumours of ghostly happenings.
The entertainment industry has made a fortune from the theme: countless films about demons, werewolves, hauntings, possessions, vampires.
But, I think, after giving it a good shake, and all the con-men and charlatans fall out, what remains are supernatural events.
I can't do this when I think deliberately about it but, if I am vacuuming (not often!), or bike cleaning or something like that, into my head pops a thought about someone. Within a few minutes whoosh! (that's the sound texts make when they arrive on my phone) and it's a text from that person.
Before mobile phones were invented I could tell who was going to ring, before they rang. I quite often know things before I am told them. It used to be a bit alarming, but I'm used to it now.