another reference: http://www.quora.com/How-do-intelligent-and-accomplished-men-who-prefer-to-date-less-accomplished-and-intelligent-women-deal-with-that-Better-yet-why/answer/Caue-C-M-Rego
Once I wrote a philosophy answer that could probably still turn out to be very unpopular on the usually difficult stack exchange community which addresses this question.
We have every reason to believe our universe is deterministic, don't we? We can already predict almost everything that happens when it does happen far enough, from macro to micro, from past to future, everything far away is very deterministic. We can't predict almost anything that's too close, like the
Yet, we are daily eluded by mind illusions of reality. Science is, at its core, a procedure to protect us from ourselves when trying to better understand reality. Do read that link.
To me it's blatantly obvious free will is an illusion, the future is just as already determined as the past and we have absolutely no choice in determining our life path.
That does not take the fun out of living it, at all. I can still jump around thinking I am changing something, and it's surprisingly enjoyable to be eluded.
In a way, the whole cosmos plays no dice. If there is no choice, there is also no random chance. When I say our life is all about luck, I simply mean we can't predict what will happen and so we call it chance. But it will happen, and it is predefined by a way too complex set of events. Way too complex. Waaaaaaay too much. If the whole Earth was a brain in itself, not even then I think could it grasp how complex it is. No one can.
But we can define the universe as set and understand the consequences.
Right now there most likely exists a comet out there that will hit Earth in the future and drastically change the climate, possibly exterminating most of life in it, again. Life around here would be mostly exterminated for the 6th time. Right now there's also a smaller comet out there that will reach the Earth surface and make no damage at all - except if it hits someone in the head.
Likewise lesser dense materials are triggering everything else that happens. Including in our neurons. As I type, you read, and our minds create an amazing illusion of time passing, we can then glance this piece of cosmos and enjoy our existence in it.
I got no idea why. It's just the way it is.