I've heard this pop up in a discussion with my physicist/engineer roommates, but didn't care to ask at the time. Now I'm mighty curious about it. Wikipedia doesn't really seem to say much on this issue.
From what I understand about the Uncertainty Principle, it says that there are certain properties of electrons and stuff that cannot be measured, and are therefore uncertain. Then Wikipedia (under indeterminism) states that Sir Arthur Eddington says that the Uncertainty Principle isn't really so because we can't measure these properties, but because turns out nature is indeterministic. At least that's what I took from those paragraphs. Even without my biased wording, it sounds more like an assertion than evidence.
I've also read a few things about how other scientific conventions perceive the issue, like how a ball on the peak of a perfect mound might randomly roll down in any direction, and I'm still unconvinced. My belief of determinism is generally that if you knew every single variable that existed as a factor at the very beginning and birth of the universe, you could correctly determine all properties of any individual particle at any point in time.
Could anyone provide some more background about this? Especially regarding quantum mechanics?