I would probably accept most experiences of precognition as natural phenomena now, although I haven't had any for some time, so it is hard to explain for sure. However, when I first began experiencing them it was so intense and the experience were of other people's deaths. I did even wonder if I was responsible for the deaths at some point, although I was able to reason that this was unlikely and that I was simply having precognitions. However, it was puzzling and, having been brought up to believe ideas such as the virgin birth of Jesus, I did end up questioning the whole basis of reality.
This whole experience of questioning was began while I was still at school, and I think that if I had not been able to explore different ideas, I would have probably have become unwell mentally. I did even request to see a psychiatrist and, fortunately, he said that he thought that I was trying too hard to compartmentalise my own experiences. Looking back on it, I am so glad that he did not try to see me as unwell. I really don't know how many people have unusual experiences, because perhaps they are fearful of speaking about them. Anyway, I struggled on and the idea which I found most helpful was Jung's idea of the collective unconscious.
Probably the reason why I began thinking about this again recently was because when I referred to this idea on the site, I felt that people seemed to think that the whole idea of the collective unconscious was dubious. So, I began thinking about the whole idea of the unconscious and what does it mean? It does seem that in some ways it refers to that which we cannot explain or understand. Obviously, people are exploring more and more about unknown aspects of life, such as the areas pointed to in the links provided by
@Outlander.
However, I definitely believe that some people are more sensitive and able to perceive subtle aspects of reality more than others. This may be about our biochemistry, and I do think that stress affects our neurotransmitters. I think that this comes into play when people become unwell mentally.
However, I think that the nature of delusions is one which is often one in psychiatry, important for diagnosis. However, the way delusions operate in daily life is not questioned that much. Even within philosophy, it seems that people are inclined to think ideas, such as belief in God, or the opposite are delusions, but we can also ask on a deeper level, what is delusion in the ultimate sense?