What are those “unclean spirits” that Jesus casts out?

The word “unclean spirit” is sometimes translated as “demon,” but that’s a tricky translation for two reasons. First, the original Greek literally translates to “unclean spirit” and, second, our word “demon” is loaded with all kinds of connotations (think of scary movies). In the ancient world, there wasn’t a division between the supernatural and the natural – the ancient Hebrew and Greek words for “spirit” is the same as their words for “wind” (ruach, pneuma). Can you identify the source of wind? Where does it come from? What about spirit, where does it come from? Unexplainable phenomena can be made sense of in all kinds of supernatural ways; therefore, the kinds of things that we might use modern methods and tools to understand (physics, medicine, etc.), ancient peoples might’ve understood in supernatural ways. – Vicar Aaron Musser