There are various stages of delusion.
A mild delusion is, say, thinking you have to count to 5 every time you walk through a doorway in order to be safe. At this level, it harms nobody except for taking up time.
A stronger delusion is thinking that there are invisible gnomes and unicorns in my garden that make it grow. I use the (correct) evidence that my garden grows to conclude (falsely) that the gnomes and unicorns exist. Part of the delusion is my thinking that a growing garden is evidence for gnomes and unicorns. This is the level of some religious believers. They believe, but it doesn't seriously affect their lives.
A stronger level of delusion happens when it is believed that the gnomes and unicorns need to be fed or treated well in order for my garden to grow. Perhaps that involves watering my garden (so the gnomes and unicorns are not thirsty). The fact that my garden then grows is taken as further proof of the existence of the gnomes and unicorns. this is the level of most religious believers. The beliefs affect their lives by taking up substantial time and energy, but there are side benefits unrelated to the actual belief that have positive effects.
An even strong level is when there is a belief that the gnomes and unicorns are everywhere and need to be appeased all the time. This can start having significant negative effects on the rest of life, including loss of friends, etc. This is closer to the level of a fundamentalist, but one who allows that others have rights also.
Finally, there is the level where I think that displeasing gnomes and unicorns is so dangerous that I am willing to imprison or kill anyone who questions their existence or the methods used to appease them. This is seriously dangerous to others. This is the level of ISIS or Jim Jones.
A mild delusion is, say, thinking you have to count to 5 every time you walk through a doorway in order to be safe. At this level, it harms nobody except for taking up time.
A stronger delusion is thinking that there are invisible gnomes and unicorns in my garden that make it grow. I use the (correct) evidence that my garden grows to conclude (falsely) that the gnomes and unicorns exist. Part of the delusion is my thinking that a growing garden is evidence for gnomes and unicorns. This is the level of some religious believers. They believe, but it doesn't seriously affect their lives.
A stronger level of delusion happens when it is believed that the gnomes and unicorns need to be fed or treated well in order for my garden to grow. Perhaps that involves watering my garden (so the gnomes and unicorns are not thirsty). The fact that my garden then grows is taken as further proof of the existence of the gnomes and unicorns. this is the level of most religious believers. The beliefs affect their lives by taking up substantial time and energy, but there are side benefits unrelated to the actual belief that have positive effects.
An even strong level is when there is a belief that the gnomes and unicorns are everywhere and need to be appeased all the time. This can start having significant negative effects on the rest of life, including loss of friends, etc. This is closer to the level of a fundamentalist, but one who allows that others have rights also.
Finally, there is the level where I think that displeasing gnomes and unicorns is so dangerous that I am willing to imprison or kill anyone who questions their existence or the methods used to appease them. This is seriously dangerous to others. This is the level of ISIS or Jim Jones.