First the background I can give. Keep in mind through all of this, I am an idiot when it comes to this stuff — if you came here for an exceptional lecture in math and science, you came to the wrong webspace. I don't understand the math behind this stuff, or even what the theories are really trying to say — rather, I use it as a jumping off point, and to rally personal excitement about the possibilities of science to break its own paradigm. I view this science very unscientifically — more as a myth or lens, rather. So if you want good science, try again.
As I understand it, quantum came about as a way of correcting problems with Newtonian mechanics, particularly on the atomic scale. Newton's theories look good on pretty large scales, but have great difficulty (in some cases even finding it impossible) dealing with things like stable atoms. It still has some compatibility issues when relativity comes drastically into play (near black holes and the like), but since we're just making all this stuff up as we go anyway, I'm sure they'll find a way to reconcile the two quite soon.
The reason I care about quantum, and the reason most partially-educated people who want to shake off the yoke of hard-line science also fall in love with it, is because (to our understanding, at least) it removes the concept of absolute knowledge. It takes Newton's clockwork universe and smashes it into tiny bits (very tiny bits, in fact), by introducing a notion of uncertainty. So instead of talking about absolute values of things in quantum, we instead find ourselves talking about the probability distributions of observables (what is the probability of obtaining each of the possible outcomes from measuring an observable).
Einstein, Rosen, Podolsky,
Made a shocking decree —
Said information just might,
Travel faster than light,
But relativity just can't agree!
If you actually delve into the theory, you find these distributions being treated in much the same way definite values have always been treated in the past, however. Which is why most of us crazies ignore the actual theory and just grab what we want to from it: There is no knowing the fundamental nature of the Universe, there is no predicting what a particle will do.
We then generalize, we expand, we extrapolate. Not just particles, but all things are random. After all, if the fundamental building blocks of the universe function in an essentially random manner, doesn't it follow that the larger amalgamations of those blocks would do the same? Oh sure, the scientists with their fancy book-learning might tell us that the probabilities balance out and we wind up with a roughly deterministic universe, but we refuse to accept that. We do it because we don't believe in a deterministic universe, and for some reason we want science to bear us out.
There once was a mighty fine cat,
Who would die at the drop of a hat —
He's alive! No he's dead...
Got to Schrodeinger's head,
And Newton's fine model went splat.
I say fuck it. Science is a fine grid through which to view the universe — it uses big words, comes up with cool concepts, and seems to work pretty well at describing the world most of us are trapped in. But if you don't believe in the universe it dictates, then for Christ's sake, stop trying to twist its theories to fit your own beliefs — if you don't have the math, if you don't have the fundamental understanding of the theories to legitimately challenge and build upon them — and just admit that you disagree with science.
I'm not saying I don't get excited about ideas that come out of modern physics, but I have learned many times that what I'm usually getting excited about is the imperfect thought-experiment being used to explain it to someone without the math or deeper understanding of the theoretical framework. The conclusions I draw from my understanding of quantum and string theory do not tend to be conclusions any scientist with a good grasp of the theories would back up at all.
When quanta start grouping en masse,
A funny thing commences to pass:
The classical limit is met,
Newton no longer need fret,
His theories hold true at long last.
Let me try to say this another way: science at this level for most us is necessarily a religion. We don't have the understanding to grok it in a meaningful way, and so we depend on priests (scientists, in this case) to tell us what is Truth and what is Not. But the process of religion doesn't stop there, it never does, we then take these Truths that have been passed down to us, and we Interpret them in such a way to make them meaningful to our own lives. If scientists get angry at this, they need to take responsibility for the fact that they have set themselves up as a priestly caste — for most people the terminology of physics is just as foreign as Church Latin, and the ideas just as counter-intuitive as a Holy Trinity.
Quantum is a mythological framework. It is like the stories of Arthur or the Teachings of Don Juan. It gives me a new lens through which to challenge my perceptions of a clockwork universe, and for that I love it. But I am not a scientist, nor do I believe in its fundamental assumption of an objectively discernable universe. So there.