From personal experience, in regards to discerning of spirits, it's definitely a thing.
One time I was on my computer and I saw a picture of a man's face. I had no idea who this man was at all, no frame of reference. I had almost an allergic reaction to him. Samuel was sitting next to me, I screamed "Oh hell no!" and slammed the lid of my computer shut. I can't really explain what I felt, but just that this guy was seriously evil, like very frighteningly so. I could feel it deep down in my spirit, but I also had a physical reaction and nearly threw up. I had to get Samuel to open the computer and slowly go through to work out who on earth this guy was.
I can't remember his name, and I don't want to google him again to find out... But he was the doctor in Nazi Germany who did nasty experiments on the Jews in concentration camps.
It was just a picture, I have no idea why I had that reaction, but there was something spiritual in it because otherwise it doesn't make any sense at all.
Another time I was praying for a friend, and while doing so YHWH gave me the names of several spirits to pray against. I didn't even know they were a problem in her life at all. I mean, we can argue all day about whether all that is biblical or not, but that's the word I was given, and that's what I did. Things have gotten better for her since I did that, and specifically in the area that one spirit was targeting.
My thoughts on this are sort of leading on to a bigger issue, but I'm going to start another thread rather than derail this one.