About a month ago I read Jesse Bering's Why is the Penis Shaped Like That? (and Other Reflections on Being Human), a collection of essays exploring various evolutionary phenomena and curios (most of them somehow centered on sexual organs or sexual activity). My favorite essay in the book wound up being the one most out of character with the rest of the text: "Scientists Say Free Will Probably Doesn't Exist, Urge 'Don't Stop Believeing!'" As you could guess from the title (a great title, by the way), the essay deals with the classic argument of free will versus determinism, with some surprising results. Specifically, a hard view of science pretty much requires a deterministic view of the universe... what makes the article interesting is that most people tend to resign themselves to a humdrum life and become depressed thinking that way - hence the "Don't Stop Believing." I've always been drawn to this argument, just as I've always been drawn to questions about God, faith, and other "big" issues. They're interesting. But a deterministic view is not one I can get behind. It makes sense - I can't deny the logic of it, or even the correctness of it - but morally I just find myself opposed to a hard deterministic view of the world.
Determinism (broadly speaking) maintains that, essentially, the conditions of the universe (or world, or human body - whatever you want to talk about) at any specific moment dictate a specific, unavoidable outcome. The timeframe on this may be only on the scale of milliseconds (which Bering's essay touches on), but those few milliseconds determine the entire history of what follows. (In one sense, this is analogous to Aristotle's "Prime Mover" argument, without the divine intervention... However, I don't want to get into the moral implications of a deterministic universe right now, so I'll stop there.)
As you should know, I got married a few months ago. And something a lot of people talk about when you're getting married - something my wife and I have discussed off and on over our years together - is the idea of a "soulmate," or if you prefer, "destiny." My wife maintains that she loves me very much, but neither she nor I believe in a soulmate - ie, only one specific person who can "complete" you. That's a nice, romantic idea, but I just don't buy it... Likewise, I don't believe in destiny - ie, being fated to do something for some grander purpose.
A destinic view seems kind of naive to me. It's nice to believe that there's some grand plan to the universe, or that we've all got some great, specific purpose to fulfill, but that doesn't work for me. From my short time on this planet, it seems quite obvious that we live in a chaotic system - ie, chance and coincidence reign, and some times (most times?) there's no greater purpose to an action other than the fact it happened. I'd rather believe that we can define our own purpose - we "choose" our destiny, so to speak.
From my view, this is the only thing that makes sense in an adult world. Remember those "moral implications" I didn't want to get into? Let's just touch on that now: if we're fated to do something, then "we" don't really exist in the true sense. If I'm destined to be a carpenter, then no matter what, I'll be a carpenter. There's no room for personality or even personal identity in that kind of framework. You're a slave to fate - bound to duty, defined by purpose. I'd rather believe that our actions have an impact, that we actually can choose to do or not do something, and that we can thus accept responsibility for our actions. Because that's really what determinism/fate/destiny are all about: who's in charge. If I was destined to be a killer, then why should I be blamed for the lives I took? If I was destined to be a doctor, then how could I take credit for the lives I saved? That's the problem.
Flip that around, now. If there is no greater purpose, no destiny, no fate, we're free to make our own choices, to pay our own prices. Everything is a result of everything else. That's a philosophy I can get behind. And in my opinion, it's even kind of romantic. My wife and I didn't wind up together because we were forced to, we wound up together because we wanted to. Isn't that nice?
Maybe it's not scientifically sound, but it's the best way I can think of to function in the world.