Wow - I had no idea there was a name for this. I've definitely experienced that feeling when standing near the edge of something, or when I have a sharp knife in my hand, etc. I'm actually cripplingly afraid of death - maybe even more so than I should be - so the explanation about the brain misinterpreting the safety signal makes sense to me more so than The Call of the Void...but then again, maybe there is something of that in my subconscious.