Precognition is the ability to foresee future events in yourdreams. Sometimes this can be quite painful for the viewer because it can be negative things that you are dreaming about. But also it makes them happy at times because of positive dreaming. From herein I will be calling the dreaming, visions.
Now, this is where the debate comes in. Some people say that what you see in your visions, will absolutely happen, and others only say sometimes. I, from personal experience, can say that only about a quarter of what I see, actually comes to be. Again, from personal experience, whenever a vision is hazier, meaning looks more like a dream than a vision, it is less likely to come, but when it is clearer, it is more likely to come. I can't say if this is the same for other people, as I have never asked, and also everyone's mind is different, so it is likely it is not the same.
I am not your normal psychic. I have been blessed with a few gifts. I do not mean to gloat, so please don't take it like that. I will say the things I am that have to do with future seeing: I am a clairvoyant, and a precognition. Some people call people with precognition, precog's to shorten it. When I was younger, I was more a precog than anything else. But as my mind has matured over the years, I am more a clairvoyant, and clairaudient. I will admit I have never had an easy life. In fact, for the most part, it has been downright crap. From herein I will call precognition night visions, and clairvoyant/audient visions. When I started having night visions, I was very scared. They were always extremely vivid. Like I was awake. The thing is, you can't really go to therapy for this. You can try and talk to someone who has the same problem as you, or someone who has gotten over that hurdle.
I got over that hurdle by shielding myself. This is generally a thing you learn and can do quickly. It is keeping that shield in place. The vividness slowly went away, then I almost never got a night vision again. I still get one about once a year, and they have always proven to be right.
Generally people are born a psychic, but I have heard and seen a lot of people, supposedly, teaching or training them self to be one. I have never heard, or seen anything like it in all of my years, and plus while reading old philosophies and whatnot. So I highly doubt this is true, but I have been proven wrong before.