Premonitions are another one of those phenomena which are very common, but which official science declares cannot exist, and therefore do not exist. A couple of years ago some folk related their premonitions on a brief TV documentary. For the sake of fairness, they also interviewed a sceptic, who explained them by a combination of chance and selective memory. To put it simply, our brains are wired to notice the exceptional events. We remember an unusual coincidence, and forget all the times our hunches or premonitions turned out false.
On the face of it, this is all very reasonable. A soldier, a bundle of nerves before a battle, declares: "I've got a bad feeling. I don't think I'm going to make it through the day." If he is killed, all his comrades remember it. If he survives, it's forgotten. In the more mundane world, you take out an umbrella when you suspect it is going to rain, but you remember particularly the time you lugged the useless thing around when the sky cleared, and you joke about how an umbrella scares the rain away. Also, since the number of random events is virtually infinite, we are all, at some stage or another, going to be presented with what looks like a remarkable coincidence.
However, on closer examination, the theory doesn't always hold.