Wikipediatells me that there is a difference between predestination and omniscience - that the former is mostly religious, and it implies God not only knows what will happen (omniscience), but had an active role in choosing things to be so. Arguably, if God did create the universe, then his omniscience would imply predestination... unless God didn't intend certain things? But that paints a very unconcerned God, and I don't think that's what most people want.
Anyway, the topic of fate and destiny came up back in June in conversation with some friends. I've been asked to write about this, but I never found the motivation to do so until now.
First, I want to state my belief that history is repeatable. That is, for some paste event, if the same person (in name as well as in time) was put in the same place at the same time, the same things would happen. This is not really a statement about fate, since the person has some freedom to choose what happens, or alternately their "choice" is already determined. This does say something about human behavior though; underneath this statement is an assumption that humans, if put in the same situation, will behave in the same way. That is, a person's beliefs together with the environment can directly predict a person's actions.
This may seem like a very deterministic view of life, but as I've said, that is not the case. Although human action will lead to the next timestep of beliefs and environment, nothing says this is a closed system. The environment may change without human intervention, as it has done so for millions of years before man arrived on the planet. More important, even with free will actions can be deterministic. For example, if a person is in a room and there's a fire, it is almost certain that person will run towards the door. Of course, he has the choice of choosing to stay, of even leap into the fire, but under normal circumstances that won't happen.
I think more interesting is the question of where free will comes from. Macroscopic physics is largely deterministic;given the positions and velocities of air molecules, for example, and the momentum and position of a coin, it's probably possible to calculate how it will land. Only on the very small scale is there something that's random: atomic decay. There is a question of whether something as impersonal as quantum mechanics really means free will. But my problem with random atomic decay has more to do with the definition of random. What appears random to us may not in fact be non-deterministic. Kolmogorov complexity(a course which I dropped) defines a random string as something which cannot be compressed; that is, there is no shorter description of the string than the string itself. Given this definition, it is conceivable that there is a book with the result of every coin toss recorded, and coin tosses merely follow this book in results. The string would be random (incompressible), but the results would actually be deterministic. Parallels can be drawn to a "random number generator" where the numbers are defined before hand by coin toss. The sequence generated are random, but you know the sequence before hand. Something like this.
Besides this free-will, determinism, and predestination thing being unknowable, it is irrelevant. Even if we are predestined to do things, we cannot know what that thing is until we actually do them. For us, it doesn't matter if the future is predetermined or is undecided; we won't know either way. You might think you are destined to change the world, and so lie on the couch all day waiting for that to happen. That, of course, won't help you change the world, and it might contribute a lot to proving you thought incorrectly. We therefore have no choice to be reject predesination/determisn, and try our hardest to do what we want, because this will give us the best "chance" of getting there. Even if the chance has always been none.
So do I believe in predestination? No. It's not provable, and since we can't use it to do other things, it's not helpful either (accept in faith). Kinda like the existance of God, actually, now I think about it.